function Q(value) {
// If the object is already a Promise, return it directly. This enables
// the resolve function to both be used to created references from objects,
// but to tolerably coerce non-promises to promises.
if (value instanceof Promise) {
return value;
}
// assimilate thenables
if (isPromiseAlike(value)) {
return coerce(value);
} else {
return fulfill(value);
}
}n/a
function promise(resolver) {
if (typeof resolver !== "function") {
throw new TypeError("resolver must be a function.");
}
var deferred = defer();
try {
resolver(deferred.resolve, deferred.reject, deferred.notify);
} catch (reason) {
deferred.reject(reason);
}
return deferred.promise;
}...
This is an alternative promise-creation API that has the same power as
the deferred concept, but without introducing another conceptual entity.
Rewriting the `requestOkText` example above using `Q.Promise`:
```javascript
function requestOkText(url) {
return Q.Promise(function(resolve, reject, notify) {
var request = new XMLHttpRequest();
request.open("GET", url, true);
request.onload = onload;
request.onerror = onerror;
request.onprogress = onprogress;
request.send();
...function all(promises) {
return when(promises, function (promises) {
var pendingCount = 0;
var deferred = defer();
array_reduce(promises, function (undefined, promise, index) {
var snapshot;
if (
isPromise(promise) &&
(snapshot = promise.inspect()).state === "fulfilled"
) {
promises[index] = snapshot.value;
} else {
++pendingCount;
when(
promise,
function (value) {
promises[index] = value;
if (--pendingCount === 0) {
deferred.resolve(promises);
}
},
deferred.reject,
function (progress) {
deferred.notify({ index: index, value: progress });
}
);
}
}, void 0);
if (pendingCount === 0) {
deferred.resolve(promises);
}
return deferred.promise;
});
}...
- Deprecated ``ref`` in favor of ``resolve`` as recommended by
@domenic.
- Update event-queue dependency.
## 0.8.1
- Fixed Opera bug. #35 @cadorn
- Fixed ``Q.all([])`` #32 @domenic
## 0.8.0
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
...allResolved = function () {
if (typeof console !== "undefined" &&
typeof console.warn === "function") {
console.warn(name + " is deprecated, use " + alternative +
" instead.", new Error("").stack);
}
return callback.apply(callback, arguments);
}n/a
function allSettled(promises) {
return Q(promises).allSettled();
}...
};
/**
* @see Promise#allSettled
*/
Q.allSettled = allSettled;
function allSettled(promises) {
return Q(promises).allSettled();
}
/**
* Turns an array of promises into a promise for an array of their states (as
* returned by `inspect`) when they have all settled.
* @param {Array[Any*]} values an array (or promise for an array) of values (or
* promises for values)
...function any(promises) {
if (promises.length === 0) {
return Q.resolve();
}
var deferred = Q.defer();
var pendingCount = 0;
array_reduce(promises, function (prev, current, index) {
var promise = promises[index];
pendingCount++;
when(promise, onFulfilled, onRejected, onProgress);
function onFulfilled(result) {
deferred.resolve(result);
}
function onRejected(err) {
pendingCount--;
if (pendingCount === 0) {
err.message = ("Q can't get fulfillment value from any promise, all " +
"promises were rejected. Last error message: " + err.message);
deferred.reject(err);
}
}
function onProgress(progress) {
deferred.notify({
index: index,
value: progress
});
}
}, undefined);
return deferred.promise;
}...
## 1.2.1
- Fix Node.js environment detection for modern Browserify (@kahnjw).
## 1.2.0
- Added Q.any(promisesArray) method (@vergara).
Returns a promise fulfilled with the value of the first resolved promise in
promisesArray. If all promises in promisesArray are rejected, it returns
a rejected promise.
## 1.1.2
- Removed extraneous files from the npm package by using the "files"
...function async(makeGenerator) {
return function () {
// when verb is "send", arg is a value
// when verb is "throw", arg is an exception
function continuer(verb, arg) {
var result;
// Until V8 3.19 / Chromium 29 is released, SpiderMonkey is the only
// engine that has a deployed base of browsers that support generators.
// However, SM's generators use the Python-inspired semantics of
// outdated ES6 drafts. We would like to support ES6, but we'd also
// like to make it possible to use generators in deployed browsers, so
// we also support Python-style generators. At some point we can remove
// this block.
if (typeof StopIteration === "undefined") {
// ES6 Generators
try {
result = generator[verb](arg);
} catch (exception) {
return reject(exception);
}
if (result.done) {
return Q(result.value);
} else {
return when(result.value, callback, errback);
}
} else {
// SpiderMonkey Generators
// FIXME: Remove this case when SM does ES6 generators.
try {
result = generator[verb](arg);
} catch (exception) {
if (isStopIteration(exception)) {
return Q(exception.value);
} else {
return reject(exception);
}
}
return when(result, callback, errback);
}
}
var generator = makeGenerator.apply(this, arguments);
var callback = continuer.bind(continuer, "next");
var errback = continuer.bind(continuer, "throw");
return callback();
};
}...
* calls the generator and also ends the promise chain, so that any
* unhandled errors are thrown instead of forwarded to the error
* handler. This is useful because it's extremely common to run
* generators at the top-level to work with libraries.
*/
Q.spawn = spawn;
function spawn(makeGenerator) {
Q.done(Q.async(makeGenerator)());
}
// FIXME: Remove this interface once ES6 generators are in SpiderMonkey.
/**
* Throws a ReturnValue exception to stop an asynchronous generator.
*
* This interface is a stop-gap measure to support generator return
...catch = function (object, rejected) {
return Q(object).then(void 0, rejected);
}...
Q.fcall(promisedStep1)
.then(promisedStep2)
.then(promisedStep3)
.then(promisedStep4)
.then(function (value4) {
// Do something with value4
})
.catch(function (error) {
// Handle any error from all above steps
})
.done();
```
With this approach, you also get implicit error propagation, just like `try`,
`catch`, and `finally`. An error in `promisedStep1` will flow all the way to
...function defer() {
// if "messages" is an "Array", that indicates that the promise has not yet
// been resolved. If it is "undefined", it has been resolved. Each
// element of the messages array is itself an array of complete arguments to
// forward to the resolved promise. We coerce the resolution value to a
// promise using the `resolve` function because it handles both fully
// non-thenable values and other thenables gracefully.
var messages = [], progressListeners = [], resolvedPromise;
var deferred = object_create(defer.prototype);
var promise = object_create(Promise.prototype);
promise.promiseDispatch = function (resolve, op, operands) {
var args = array_slice(arguments);
if (messages) {
messages.push(args);
if (op === "when" && operands[1]) { // progress operand
progressListeners.push(operands[1]);
}
} else {
Q.nextTick(function () {
resolvedPromise.promiseDispatch.apply(resolvedPromise, args);
});
}
};
// XXX deprecated
promise.valueOf = function () {
if (messages) {
return promise;
}
var nearerValue = nearer(resolvedPromise);
if (isPromise(nearerValue)) {
resolvedPromise = nearerValue; // shorten chain
}
return nearerValue;
};
promise.inspect = function () {
if (!resolvedPromise) {
return { state: "pending" };
}
return resolvedPromise.inspect();
};
if (Q.longStackSupport && hasStacks) {
try {
throw new Error();
} catch (e) {
// NOTE: don't try to use `Error.captureStackTrace` or transfer the
// accessor around; that causes memory leaks as per GH-111. Just
// reify the stack trace as a string ASAP.
//
// At the same time, cut off the first line; it's always just
// "[object Promise]\n", as per the `toString`.
promise.stack = e.stack.substring(e.stack.indexOf("\n") + 1);
promise.stackCounter = longStackCounter++;
}
}
// NOTE: we do the checks for `resolvedPromise` in each method, instead of
// consolidating them into `become`, since otherwise we'd create new
// promises with the lines `become(whatever(value))`. See e.g. GH-252.
function become(newPromise) {
resolvedPromise = newPromise;
if (Q.longStackSupport && hasStacks) {
// Only hold a reference to the new promise if long stacks
// are enabled to reduce memory usage
promise.source = newPromise;
}
array_reduce(messages, function (undefined, message) {
Q.nextTick(function () {
newPromise.promiseDispatch.apply(newPromise, message);
});
}, void 0);
messages = void 0;
progressListeners = void 0;
}
deferred.promise = promise;
deferred.resolve = function (value) {
if (resolvedPromise) {
return;
}
become(Q(value));
};
deferred.fulfill = function (value) {
if (resolvedPromise) {
return;
}
become(fulfill(value));
};
deferred.reject = function (reason) {
if (resolvedPromise) {
return;
}
become(reject(reason));
};
deferred.notify = function (progress) {
if (resolvedPromise) {
return;
}
array_reduce(progressListeners, function (undefined, progressListener) {
Q.nextTick(function () {
progressListener(progress);
});
}, void 0);
};
return deferred;
}...
Q.any = any;
function any(promises) {
if (promises.length === 0) {
return Q.resolve();
}
var deferred = Q.defer();
var pendingCount = 0;
array_reduce(promises, function (prev, current, index) {
var promise = promises[index];
pendingCount++;
when(promise, onFulfilled, onRejected, onProgress);
...del = function (object, key) {
return Q(object).dispatch("delete", [key]);
}...
promises, so they can be chained.
```
direct manipulation using a promise as a proxy
-------------------------- -------------------------------
value.foo promise.get("foo")
value.foo = value promise.put("foo", value)
delete value.foo promise.del("foo")
value.foo(...args) promise.post("foo", [args])
value.foo(...args) promise.invoke("foo", ...args)
value(...args) promise.fapply([args])
value(...args) promise.fcall(...args)
```
If the promise is a proxy for a remote object, you can shave
...delay = function (object, timeout) {
if (timeout === void 0) {
timeout = object;
object = void 0;
}
return Q(object).delay(timeout);
}...
* If the given promise rejects, that is passed immediately.
*/
Q.delay = function (object, timeout) {
if (timeout === void 0) {
timeout = object;
object = void 0;
}
return Q(object).delay(timeout);
};
Promise.prototype.delay = function (timeout) {
return this.then(function (value) {
var deferred = defer();
setTimeout(function () {
deferred.resolve(value);
...delete = function (object, key) {
return Q(object).dispatch("delete", [key]);
}n/a
denodeify = function (callback) {
if (callback === undefined) {
throw new Error("Q can't wrap an undefined function");
}
var baseArgs = array_slice(arguments, 1);
return function () {
var nodeArgs = baseArgs.concat(array_slice(arguments));
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(callback).fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
}...
return Q.ninvoke(redisClient, "get", "user:1:id");
return Q.npost(redisClient, "get", ["user:1:id"]);
```
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
return readFile("foo.txt", "utf-8");
var redisClientGet = Q.nbind(redisClient.get, redisClient);
return redisClientGet("user:1:id");
```
Finally, if you're working with raw deferred objects, there is a
...function dispatch(object, op, args) {
return Q(object).dispatch(op, args);
}...
* @param object* the recipient
* @param op the name of the message operation, e.g., "when",
* @param args further arguments to be forwarded to the operation
* @returns result {Promise} a promise for the result of the operation
*/
Q.dispatch = dispatch;
function dispatch(object, op, args) {
return Q(object).dispatch(op, args);
}
Promise.prototype.dispatch = function (op, args) {
var self = this;
var deferred = defer();
Q.nextTick(function () {
self.promiseDispatch(deferred.resolve, op, args);
...done = function (object, fulfilled, rejected, progress) {
return Q(object).done(fulfilled, rejected, progress);
}...
* calls the generator and also ends the promise chain, so that any
* unhandled errors are thrown instead of forwarded to the error
* handler. This is useful because it's extremely common to run
* generators at the top-level to work with libraries.
*/
Q.spawn = spawn;
function spawn(makeGenerator) {
Q.done(Q.async(makeGenerator)());
}
// FIXME: Remove this interface once ES6 generators are in SpiderMonkey.
/**
* Throws a ReturnValue exception to stop an asynchronous generator.
*
* This interface is a stop-gap measure to support generator return
...fail = function (object, rejected) {
return Q(object).then(void 0, rejected);
}...
return Q(callback).nfapply(args);
};
Promise.prototype.nfapply = function (args) {
var deferred = defer();
var nodeArgs = array_slice(args);
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
...fapply = function (object, args) {
return Q(object).dispatch("apply", [void 0, args]);
}...
return Q(callback).nfapply(args);
};
Promise.prototype.nfapply = function (args) {
var deferred = defer();
var nodeArgs = array_slice(args);
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
...fbind = function (object) {
var promise = Q(object);
var args = array_slice(arguments, 1);
return function fbound() {
return promise.dispatch("apply", [
this,
args.concat(array_slice(arguments))
]);
};
}n/a
fcall = function (object) {
return Q(object).dispatch("apply", [void 0, array_slice(arguments, 1)]);
}...
* .tap(console.log)
* .then(...);
*/
Promise.prototype.tap = function (callback) {
callback = Q(callback);
return this.then(function (value) {
return callback.fcall(value).thenResolve(value);
});
};
/**
* Registers an observer on a promise.
*
* Guarantees:
...fin = function (object, callback) {
return Q(object)["finally"](callback);
}...
returned by ``getInputPromise()`` either returns a value or throws an
error. The value returned or error thrown by ``getInputPromise()``
passes directly to ``outputPromise`` unless the final handler fails, and
may be delayed if the final handler returns a promise.
```javascript
var outputPromise = getInputPromise()
.fin(function () {
// close files, database connections, stop servers, conclude tests
});
```
- If the handler returns a value, the value is ignored
- If the handler throws an error, the error passes to ``outputPromise``
- If the handler returns a promise, ``outputPromise`` gets postponed. The
...finally = function (object, callback) {
return Q(object)["finally"](callback);
}n/a
function fulfill(value) {
return Promise({
"when": function () {
return value;
},
"get": function (name) {
return value[name];
},
"set": function (name, rhs) {
value[name] = rhs;
},
"delete": function (name) {
delete value[name];
},
"post": function (name, args) {
// Mark Miller proposes that post with no name should apply a
// promised function.
if (name === null || name === void 0) {
return value.apply(void 0, args);
} else {
return value[name].apply(value, args);
}
},
"apply": function (thisp, args) {
return value.apply(thisp, args);
},
"keys": function () {
return object_keys(value);
}
}, void 0, function inspect() {
return { state: "fulfilled", value: value };
});
}n/a
get = function (object, key) {
return Q(object).dispatch("get", [key]);
}...
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
term ``def`` was too confusing to new users.
- WARNING: ``spy`` removed in favor of ``fin``.
- WARNING: ``wait`` removed. Do ``all(args).get(0)`` instead.
- WARNING: ``join`` removed. Do ``all(args).spread(callback)`` instead.
- WARNING: Removed the ``Q`` function module.exports alias
for ``Q.ref``. It conflicts with ``Q.apply`` in weird
ways, making it uncallable.
- Revised ``delay`` so that it accepts both ``(value,
timeout)`` and ``(timeout)`` variations based on
arguments length.
...getUnhandledReasons = function () {
// Make a copy so that consumers can't interfere with our internal state.
return unhandledReasons.slice();
}n/a
invoke = function (object, name) {
return Q(object).dispatch("post", [name, array_slice(arguments, 2)]);
}...
```
If there is any chance that the promise you receive is not a Q promise
as provided by your library, you should wrap it using a Q function.
You can even use ``Q.invoke`` as a shorthand.
```javascript
return Q.invoke($, 'ajax', ...)
.then(function () {
});
```
### Over the Wire
...function isFulfilled(object) {
return !isPromise(object) || object.inspect().state === "fulfilled";
}n/a
function isPending(object) {
return isPromise(object) && object.inspect().state === "pending";
}n/a
function isPromise(object) {
return object instanceof Promise;
}n/a
function isPromiseAlike(object) {
return isObject(object) && typeof object.then === "function";
}n/a
function isRejected(object) {
return isPromise(object) && object.inspect().state === "rejected";
}n/a
join = function (x, y) {
return Q(x).join(y);
}...
if (p.stack && (!error.__minimumStackCounter__ || error.__minimumStackCounter__ > p.stackCounter)) {
object_defineProperty(error, "__minimumStackCounter__", {value: p.stackCounter, configurable: true});
stacks.unshift(p.stack);
}
}
stacks.unshift(error.stack);
var concatedStacks = stacks.join("\n" + STACK_JUMP_SEPARATOR + "\n
");
var stack = filterStackString(concatedStacks);
object_defineProperty(error, "stack", {value: stack, configurable: true});
}
}
function filterStackString(stackString) {
var lines = stackString.split("\n");
...keys = function (object) {
return Q(object).dispatch("keys", []);
}n/a
function Promise(descriptor, fallback, inspect) {
if (fallback === void 0) {
fallback = function (op) {
return reject(new Error(
"Promise does not support operation: " + op
));
};
}
if (inspect === void 0) {
inspect = function () {
return {state: "unknown"};
};
}
var promise = object_create(Promise.prototype);
promise.promiseDispatch = function (resolve, op, args) {
var result;
try {
if (descriptor[op]) {
result = descriptor[op].apply(promise, args);
} else {
result = fallback.call(promise, op, args);
}
} catch (exception) {
result = reject(exception);
}
if (resolve) {
resolve(result);
}
};
promise.inspect = inspect;
// XXX deprecated `valueOf` and `exception` support
if (inspect) {
var inspected = inspect();
if (inspected.state === "rejected") {
promise.exception = inspected.reason;
}
promise.valueOf = function () {
var inspected = inspect();
if (inspected.state === "pending" ||
inspected.state === "rejected") {
return promise;
}
return inspected.value;
};
}
return promise;
}n/a
mapply = function (object, name, args) {
return Q(object).dispatch("post", [name, args]);
}n/a
function master(object) {
return Promise({
"isDef": function () {}
}, function fallback(op, args) {
return dispatch(object, op, args);
}, function () {
return Q(object).inspect();
});
}n/a
mcall = function (object, name) {
return Q(object).dispatch("post", [name, array_slice(arguments, 2)]);
}n/a
nbind = function (callback, thisp) {
var baseArgs = array_slice(arguments, 2);
return function () {
var nodeArgs = baseArgs.concat(array_slice(arguments));
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
function bound() {
return callback.apply(thisp, arguments);
}
Q(bound).fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
}...
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
return readFile("foo.txt", "utf-8");
var redisClientGet = Q.nbind(redisClient.get, redisClient);
return redisClientGet("user:1:id");
```
Finally, if you're working with raw deferred objects, there is a
`makeNodeResolver` method on deferreds that can be handy:
```javascript
...function nearer(value) {
if (isPromise(value)) {
var inspected = value.inspect();
if (inspected.state === "fulfilled") {
return inspected.value;
}
}
return value;
}n/a
nextTick = function (task) {
tail = tail.next = {
task: task,
domain: isNodeJS && process.domain,
next: null
};
if (!flushing) {
flushing = true;
requestTick();
}
}...
// `setTimeout`. In this case `setImmediate` is preferred because
// it is faster. Browserify's `process.toString()` yields
// "[object Object]", while in a real Node environment
// `process.toString()` yields "[object process]".
isNodeJS = true;
requestTick = function () {
process.nextTick(flush);
};
} else if (typeof setImmediate === "function") {
// In IE10, Node.js 0.9+, or https://github.com/NobleJS/setImmediate
if (typeof window !== "undefined") {
requestTick = setImmediate.bind(window, flush);
} else {
...nfapply = function (callback, args) {
return Q(callback).nfapply(args);
}...
});
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided as an array, and returns a promise.
*
* Q.nfapply(FS.readFile, [__filename])
* .then(function (content) {
* })
*
*/
Q.nfapply = function (callback, args) {
return Q(callback).nfapply(args);
};
...nfbind = function (callback) {
if (callback === undefined) {
throw new Error("Q can't wrap an undefined function");
}
var baseArgs = array_slice(arguments, 1);
return function () {
var nodeArgs = baseArgs.concat(array_slice(arguments));
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(callback).fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
}...
return deferred.promise;
};
/**
* Wraps a NodeJS continuation passing function and returns an equivalent
* version that returns a promise.
* @example
* Q.nfbind(FS.readFile, __filename)("utf-8")
* .then(console.log)
* .done()
*/
Q.nfbind =
Q.denodeify = function (callback /*...args*/) {
if (callback === undefined) {
throw new Error("Q can't wrap an undefined function");
...nfcall = function (callback) {
var args = array_slice(arguments, 1);
return Q(callback).nfapply(args);
}...
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
* Q.nfcall(FS.readFile, __filename)
* .then(function (content) {
* })
*
*/
Q.nfcall = function (callback /*...args*/) {
var args = array_slice(arguments, 1);
return Q(callback).nfapply(args);
...ninvoke = function (object, name) {
var nodeArgs = array_slice(arguments, 2);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(object).dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}...
If you are working with methods, instead of simple functions, you can easily
run in to the usual problems where passing a method to another function—like
`Q.nfcall`—"un-binds" the method from its owner. To avoid this, you can either
use `Function.prototype.bind` or some nice shortcut methods we provide:
```javascript
return Q.ninvoke(redisClient, "get", "user:1:id");
return Q.npost(redisClient, "get", ["user:1:id"]);
```
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
...nmapply = function (object, name, args) {
return Q(object).npost(name, args);
}n/a
nmcall = function (object, name) {
var nodeArgs = array_slice(arguments, 2);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(object).dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}n/a
noConflict = function () {
throw new Error("Q.noConflict only works when Q is used as a global");
}n/a
function nodeify(object, nodeback) {
return Q(object).nodeify(nodeback);
}...
* pass a nodeback, they will receive the result promise.
* @param object a result (or a promise for a result)
* @param {Function} nodeback a Node.js-style callback
* @returns either the promise or nothing
*/
Q.nodeify = nodeify;
function nodeify(object, nodeback) {
return Q(object).nodeify(nodeback);
}
Promise.prototype.nodeify = function (nodeback) {
if (nodeback) {
this.then(function (value) {
Q.nextTick(function () {
nodeback(null, value);
...npost = function (object, name, args) {
return Q(object).npost(name, args);
}...
* @param {String} name name of the method of object
* @param {Array} args arguments to pass to the method; the callback
* will be provided by Q and appended to these arguments.
* @returns a promise for the value or error
*/
Q.nmapply = // XXX As proposed by "Redsandro"
Q.npost = function (object, name, args) {
return Q(object).npost(name, args);
};
Promise.prototype.nmapply = // XXX As proposed by "Redsandro"
Promise.prototype.npost = function (name, args) {
var nodeArgs = array_slice(args || []);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
...nsend = function (object, name) {
var nodeArgs = array_slice(arguments, 2);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(object).dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}n/a
passByCopy = function (object) {
//freeze(object);
//passByCopies.set(object, true);
return object;
}n/a
post = function (object, name, args) {
return Q(object).dispatch("post", [name, args]);
}...
```
direct manipulation using a promise as a proxy
-------------------------- -------------------------------
value.foo promise.get("foo")
value.foo = value promise.put("foo", value)
delete value.foo promise.del("foo")
value.foo(...args) promise.post("foo", [args])
value.foo(...args) promise.invoke("foo", ...args)
value(...args) promise.fapply([args])
value(...args) promise.fcall(...args)
```
If the promise is a proxy for a remote object, you can shave
round-trips by using these functions instead of ``then``. To take
...function progress(object, progressed) {
return Q(object).then(void 0, void 0, progressed);
}...
promise.
## 0.8.9
- Added ``nend``
- Added preliminary progress notification support, via
``promise.then(onFulfilled, onRejected, onProgress)``,
``promise.progress(onProgress)``, and ``deferred.notify(...progressData)``.
- Made ``put`` and ``del`` return the object acted upon for easier chaining.
#84
- Fixed coercion cycles with cooperating promises. #106
## 0.8.7
- Support [Montage Require](http://github.com/kriskowal/mr)
...function promise(resolver) {
if (typeof resolver !== "function") {
throw new TypeError("resolver must be a function.");
}
var deferred = defer();
try {
resolver(deferred.resolve, deferred.reject, deferred.notify);
} catch (reason) {
deferred.reject(reason);
}
return deferred.promise;
}...
and the message now includes the duration of the timeout in
miliseconds. This doesn't constitute (in my opinion) a
backward-incompatibility since it is a change of an undocumented and
unspecified public behavior, but if you happened to depend on the
exception being a string, you will need to revise your code.
- Added ``deferred.makeNodeResolver()`` to replace the more cryptic
``deferred.node()`` method.
- Added experimental ``Q.promise(maker(resolve, reject))`` to make a
promise inside a callback, such that thrown exceptions in the
callback are converted and the resolver and rejecter are arguments.
This is a shorthand for making a deferred directly and inspired by
@gozala’s stream constructor pattern and the Microsoft Windows Metro
Promise constructor interface.
- Added experimental ``Q.begin()`` that is intended to kick off chains
of ``.then`` so that each of these can be reordered without having to
...function promised(callback) {
return function () {
return spread([this, all(arguments)], function (self, args) {
return callback.apply(self, args);
});
};
}...
/**
* The promised function decorator ensures that any promise arguments
* are settled and passed as values (`this` is also settled and passed
* as a value). It will also ensure that the result of a function is
* always a promise.
*
* @example
* var add = Q.promised(function (a, b) {
* return a + b;
* });
* add(Q(a), Q(B));
*
* @param {function} callback The function to decorate
* @returns {function} a function that has been decorated.
*/
...function race(answerPs) {
return promise(function (resolve, reject) {
// Switch to this once we can assume at least ES5
// answerPs.forEach(function (answerP) {
// Q(answerP).then(resolve, reject);
// });
// Use this in the meantime
for (var i = 0, len = answerPs.length; i < len; i++) {
Q(answerPs[i]).then(resolve, reject);
}
});
}n/a
function reject(reason) {
var rejection = Promise({
"when": function (rejected) {
// note that the error has been handled
if (rejected) {
untrackRejection(this);
}
return rejected ? rejected(reason) : this;
}
}, function fallback() {
return this;
}, function inspect() {
return { state: "rejected", reason: reason };
});
// Note that the reason has not been handled.
trackRejection(rejection, reason);
return rejection;
}...
* promise.
* @returns a nodeback
*/
defer.prototype.makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
};
...function resetUnhandledRejections() {
unhandledReasons.length = 0;
unhandledRejections.length = 0;
if (!trackUnhandledRejections) {
trackUnhandledRejections = true;
}
}n/a
function Q(value) {
// If the object is already a Promise, return it directly. This enables
// the resolve function to both be used to created references from objects,
// but to tolerably coerce non-promises to promises.
if (value instanceof Promise) {
return value;
}
// assimilate thenables
if (isPromiseAlike(value)) {
return coerce(value);
} else {
return fulfill(value);
}
}...
*/
defer.prototype.makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
};
/**
...function _return(value) {
throw new QReturnValue(value);
}...
* var bar = yield getBarPromise();
* return foo + bar;
* })
* // Older SpiderMonkey style
* Q.async(function () {
* var foo = yield getFooPromise();
* var bar = yield getBarPromise();
* Q.return(foo + bar);
* })
*/
Q["return"] = _return;
function _return(value) {
throw new QReturnValue(value);
}
...send = function (object, name) {
return Q(object).dispatch("post", [name, array_slice(arguments, 2)]);
}...
var request = new XMLHttpRequest();
var deferred = Q.defer();
request.open("GET", url, true);
request.onload = onload;
request.onerror = onerror;
request.onprogress = onprogress;
request.send();
function onload() {
if (request.status === 200) {
deferred.resolve(request.responseText);
} else {
deferred.reject(new Error("Status code was " + request.status));
}
...set = function (object, key, value) {
return Q(object).dispatch("set", [key, value]);
}...
promise.resolve = Q; // ES6
// XXX experimental. This method is a way to denote that a local value is
// serializable and should be immediately dispatched to a remote upon request,
// instead of passing a reference.
Q.passByCopy = function (object) {
//freeze(object);
//passByCopies.set(object, true);
return object;
};
Promise.prototype.passByCopy = function () {
//freeze(object);
//passByCopies.set(object, true);
return this;
...function spawn(makeGenerator) {
Q.done(Q.async(makeGenerator)());
}n/a
function spread(value, fulfilled, rejected) {
return Q(value).spread(fulfilled, rejected);
}...
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
term ``def`` was too confusing to new users.
- WARNING: ``spy`` removed in favor of ``fin``.
- WARNING: ``wait`` removed. Do ``all(args).get(0)`` instead.
- WARNING: ``join`` removed. Do ``all(args).spread(callback)`` instead.
- WARNING: Removed the ``Q`` function module.exports alias
for ``Q.ref``. It conflicts with ``Q.apply`` in weird
ways, making it uncallable.
- Revised ``delay`` so that it accepts both ``(value,
timeout)`` and ``(timeout)`` variations based on
arguments length.
- Added ``ref().spread(cb(...args))``, a variant of
...stopUnhandledRejectionTracking = function () {
resetUnhandledRejections();
trackUnhandledRejections = false;
}n/a
tap = function (promise, callback) {
return Q(promise).tap(callback);
}...
}
}]);
return deferred.promise;
};
Q.tap = function (promise, callback) {
return Q(promise).tap(callback);
};
/**
* Works almost like "finally", but not called for rejections.
* Original resolution value is passed through callback unaffected.
* Callback may return a promise that will be awaited for.
* @param {Function} callback
...thenReject = function (promise, reason) {
return Q(promise).thenReject(reason);
}...
};
Promise.prototype.thenReject = function (reason) {
return this.then(function () { throw reason; });
};
Q.thenReject = function (promise, reason) {
return Q(promise).thenReject(reason);
};
/**
* If an object is not a promise, it is as "near" as possible.
* If a promise is rejected, it is as "near" as possible too.
* If it’s a fulfilled promise, the fulfillment value is nearer.
* If it’s a deferred promise and the deferred has been resolved, the
...thenResolve = function (promise, value) {
return Q(promise).thenResolve(value);
}...
* .tap(console.log)
* .then(...);
*/
Promise.prototype.tap = function (callback) {
callback = Q(callback);
return this.then(function (value) {
return callback.fcall(value).thenResolve(value);
});
};
/**
* Registers an observer on a promise.
*
* Guarantees:
...timeout = function (object, ms, error) {
return Q(object).timeout(ms, error);
}...
* @param {Any*} promise
* @param {Number} milliseconds timeout
* @param {Any*} custom error message or Error object (optional)
* @returns a promise for the resolution of the given promise if it is
* fulfilled before the timeout, otherwise rejected.
*/
Q.timeout = function (object, ms, error) {
return Q(object).timeout(ms, error);
};
Promise.prototype.timeout = function (ms, error) {
var deferred = defer();
var timeoutId = setTimeout(function () {
if (!error || "string" === typeof error) {
error = new Error(error || "Timed out after " + ms + " ms");
...try = function (object) {
return Q(object).dispatch("apply", [void 0, array_slice(arguments, 1)]);
}n/a
function when(value, fulfilled, rejected, progressed) {
return Q(value).then(fulfilled, rejected, progressed);
}...
```
This is a simplified implementation of ``Q.timeout``
```javascript
function timeout(promise, ms) {
var deferred = Q.defer();
Q.when(promise, deferred.resolve);
delay(ms).then(function () {
deferred.reject(new Error("Timed out"));
});
return deferred.promise;
}
```
...function promise(resolver) {
if (typeof resolver !== "function") {
throw new TypeError("resolver must be a function.");
}
var deferred = defer();
try {
resolver(deferred.resolve, deferred.reject, deferred.notify);
} catch (reason) {
deferred.reject(reason);
}
return deferred.promise;
}...
This is an alternative promise-creation API that has the same power as
the deferred concept, but without introducing another conceptual entity.
Rewriting the `requestOkText` example above using `Q.Promise`:
```javascript
function requestOkText(url) {
return Q.Promise(function(resolve, reject, notify) {
var request = new XMLHttpRequest();
request.open("GET", url, true);
request.onload = onload;
request.onerror = onerror;
request.onprogress = onprogress;
request.send();
...function all(promises) {
return when(promises, function (promises) {
var pendingCount = 0;
var deferred = defer();
array_reduce(promises, function (undefined, promise, index) {
var snapshot;
if (
isPromise(promise) &&
(snapshot = promise.inspect()).state === "fulfilled"
) {
promises[index] = snapshot.value;
} else {
++pendingCount;
when(
promise,
function (value) {
promises[index] = value;
if (--pendingCount === 0) {
deferred.resolve(promises);
}
},
deferred.reject,
function (progress) {
deferred.notify({ index: index, value: progress });
}
);
}
}, void 0);
if (pendingCount === 0) {
deferred.resolve(promises);
}
return deferred.promise;
});
}...
- Deprecated ``ref`` in favor of ``resolve`` as recommended by
@domenic.
- Update event-queue dependency.
## 0.8.1
- Fixed Opera bug. #35 @cadorn
- Fixed ``Q.all([])`` #32 @domenic
## 0.8.0
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
...function race(answerPs) {
return promise(function (resolve, reject) {
// Switch to this once we can assume at least ES5
// answerPs.forEach(function (answerP) {
// Q(answerP).then(resolve, reject);
// });
// Use this in the meantime
for (var i = 0, len = answerPs.length; i < len; i++) {
Q(answerPs[i]).then(resolve, reject);
}
});
}n/a
function reject(reason) {
var rejection = Promise({
"when": function (rejected) {
// note that the error has been handled
if (rejected) {
untrackRejection(this);
}
return rejected ? rejected(reason) : this;
}
}, function fallback() {
return this;
}, function inspect() {
return { state: "rejected", reason: reason };
});
// Note that the reason has not been handled.
trackRejection(rejection, reason);
return rejection;
}...
* promise.
* @returns a nodeback
*/
defer.prototype.makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
};
...function Q(value) {
// If the object is already a Promise, return it directly. This enables
// the resolve function to both be used to created references from objects,
// but to tolerably coerce non-promises to promises.
if (value instanceof Promise) {
return value;
}
// assimilate thenables
if (isPromiseAlike(value)) {
return coerce(value);
} else {
return fulfill(value);
}
}...
*/
defer.prototype.makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
};
/**
...function defer() {
// if "messages" is an "Array", that indicates that the promise has not yet
// been resolved. If it is "undefined", it has been resolved. Each
// element of the messages array is itself an array of complete arguments to
// forward to the resolved promise. We coerce the resolution value to a
// promise using the `resolve` function because it handles both fully
// non-thenable values and other thenables gracefully.
var messages = [], progressListeners = [], resolvedPromise;
var deferred = object_create(defer.prototype);
var promise = object_create(Promise.prototype);
promise.promiseDispatch = function (resolve, op, operands) {
var args = array_slice(arguments);
if (messages) {
messages.push(args);
if (op === "when" && operands[1]) { // progress operand
progressListeners.push(operands[1]);
}
} else {
Q.nextTick(function () {
resolvedPromise.promiseDispatch.apply(resolvedPromise, args);
});
}
};
// XXX deprecated
promise.valueOf = function () {
if (messages) {
return promise;
}
var nearerValue = nearer(resolvedPromise);
if (isPromise(nearerValue)) {
resolvedPromise = nearerValue; // shorten chain
}
return nearerValue;
};
promise.inspect = function () {
if (!resolvedPromise) {
return { state: "pending" };
}
return resolvedPromise.inspect();
};
if (Q.longStackSupport && hasStacks) {
try {
throw new Error();
} catch (e) {
// NOTE: don't try to use `Error.captureStackTrace` or transfer the
// accessor around; that causes memory leaks as per GH-111. Just
// reify the stack trace as a string ASAP.
//
// At the same time, cut off the first line; it's always just
// "[object Promise]\n", as per the `toString`.
promise.stack = e.stack.substring(e.stack.indexOf("\n") + 1);
promise.stackCounter = longStackCounter++;
}
}
// NOTE: we do the checks for `resolvedPromise` in each method, instead of
// consolidating them into `become`, since otherwise we'd create new
// promises with the lines `become(whatever(value))`. See e.g. GH-252.
function become(newPromise) {
resolvedPromise = newPromise;
if (Q.longStackSupport && hasStacks) {
// Only hold a reference to the new promise if long stacks
// are enabled to reduce memory usage
promise.source = newPromise;
}
array_reduce(messages, function (undefined, message) {
Q.nextTick(function () {
newPromise.promiseDispatch.apply(newPromise, message);
});
}, void 0);
messages = void 0;
progressListeners = void 0;
}
deferred.promise = promise;
deferred.resolve = function (value) {
if (resolvedPromise) {
return;
}
become(Q(value));
};
deferred.fulfill = function (value) {
if (resolvedPromise) {
return;
}
become(fulfill(value));
};
deferred.reject = function (reason) {
if (resolvedPromise) {
return;
}
become(reject(reason));
};
deferred.notify = function (progress) {
if (resolvedPromise) {
return;
}
array_reduce(progressListeners, function (undefined, progressListener) {
Q.nextTick(function () {
progressListener(progress);
});
}, void 0);
};
return deferred;
}...
Q.any = any;
function any(promises) {
if (promises.length === 0) {
return Q.resolve();
}
var deferred = Q.defer();
var pendingCount = 0;
array_reduce(promises, function (prev, current, index) {
var promise = promises[index];
pendingCount++;
when(promise, onFulfilled, onRejected, onProgress);
...makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
}...
- WARNING: ``promise.timeout`` is now rejected with an ``Error`` object
and the message now includes the duration of the timeout in
miliseconds. This doesn't constitute (in my opinion) a
backward-incompatibility since it is a change of an undocumented and
unspecified public behavior, but if you happened to depend on the
exception being a string, you will need to revise your code.
- Added ``deferred.makeNodeResolver()`` to replace the more cryptic
``deferred.node()`` method.
- Added experimental ``Q.promise(maker(resolve, reject))`` to make a
promise inside a callback, such that thrown exceptions in the
callback are converted and the resolver and rejecter are arguments.
This is a shorthand for making a deferred directly and inspired by
@gozala’s stream constructor pattern and the Microsoft Windows Metro
Promise constructor interface.
...function Promise(descriptor, fallback, inspect) {
if (fallback === void 0) {
fallback = function (op) {
return reject(new Error(
"Promise does not support operation: " + op
));
};
}
if (inspect === void 0) {
inspect = function () {
return {state: "unknown"};
};
}
var promise = object_create(Promise.prototype);
promise.promiseDispatch = function (resolve, op, args) {
var result;
try {
if (descriptor[op]) {
result = descriptor[op].apply(promise, args);
} else {
result = fallback.call(promise, op, args);
}
} catch (exception) {
result = reject(exception);
}
if (resolve) {
resolve(result);
}
};
promise.inspect = inspect;
// XXX deprecated `valueOf` and `exception` support
if (inspect) {
var inspected = inspect();
if (inspected.state === "rejected") {
promise.exception = inspected.reason;
}
promise.valueOf = function () {
var inspected = inspect();
if (inspected.state === "pending" ||
inspected.state === "rejected") {
return promise;
}
return inspected.value;
};
}
return promise;
}n/a
all = function () {
return all(this);
}...
- Deprecated ``ref`` in favor of ``resolve`` as recommended by
@domenic.
- Update event-queue dependency.
## 0.8.1
- Fixed Opera bug. #35 @cadorn
- Fixed ``Q.all([])`` #32 @domenic
## 0.8.0
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
...allResolved = function () {
return allResolved(this);
}n/a
allSettled = function () {
return this.then(function (promises) {
return all(array_map(promises, function (promise) {
promise = Q(promise);
function regardless() {
return promise.inspect();
}
return promise.then(regardless, regardless);
}));
});
}...
};
/**
* @see Promise#allSettled
*/
Q.allSettled = allSettled;
function allSettled(promises) {
return Q(promises).allSettled();
}
/**
* Turns an array of promises into a promise for an array of their states (as
* returned by `inspect`) when they have all settled.
* @param {Array[Any*]} values an array (or promise for an array) of values (or
* promises for values)
...any = function () {
return any(this);
}...
## 1.2.1
- Fix Node.js environment detection for modern Browserify (@kahnjw).
## 1.2.0
- Added Q.any(promisesArray) method (@vergara).
Returns a promise fulfilled with the value of the first resolved promise in
promisesArray. If all promises in promisesArray are rejected, it returns
a rejected promise.
## 1.1.2
- Removed extraneous files from the npm package by using the "files"
...catch = function (rejected) {
return this.then(void 0, rejected);
}...
Q.fcall(promisedStep1)
.then(promisedStep2)
.then(promisedStep3)
.then(promisedStep4)
.then(function (value4) {
// Do something with value4
})
.catch(function (error) {
// Handle any error from all above steps
})
.done();
```
With this approach, you also get implicit error propagation, just like `try`,
`catch`, and `finally`. An error in `promisedStep1` will flow all the way to
...del = function (key) {
return this.dispatch("delete", [key]);
}...
promises, so they can be chained.
```
direct manipulation using a promise as a proxy
-------------------------- -------------------------------
value.foo promise.get("foo")
value.foo = value promise.put("foo", value)
delete value.foo promise.del("foo")
value.foo(...args) promise.post("foo", [args])
value.foo(...args) promise.invoke("foo", ...args)
value(...args) promise.fapply([args])
value(...args) promise.fcall(...args)
```
If the promise is a proxy for a remote object, you can shave
...delay = function (timeout) {
return this.then(function (value) {
var deferred = defer();
setTimeout(function () {
deferred.resolve(value);
}, timeout);
return deferred.promise;
});
}...
* If the given promise rejects, that is passed immediately.
*/
Q.delay = function (object, timeout) {
if (timeout === void 0) {
timeout = object;
object = void 0;
}
return Q(object).delay(timeout);
};
Promise.prototype.delay = function (timeout) {
return this.then(function (value) {
var deferred = defer();
setTimeout(function () {
deferred.resolve(value);
...delete = function (key) {
return this.dispatch("delete", [key]);
}n/a
denodeify = function () {
var args = array_slice(arguments);
args.unshift(this);
return Q.denodeify.apply(void 0, args);
}...
return Q.ninvoke(redisClient, "get", "user:1:id");
return Q.npost(redisClient, "get", ["user:1:id"]);
```
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
return readFile("foo.txt", "utf-8");
var redisClientGet = Q.nbind(redisClient.get, redisClient);
return redisClientGet("user:1:id");
```
Finally, if you're working with raw deferred objects, there is a
...dispatch = function (op, args) {
var self = this;
var deferred = defer();
Q.nextTick(function () {
self.promiseDispatch(deferred.resolve, op, args);
});
return deferred.promise;
}...
* @param object* the recipient
* @param op the name of the message operation, e.g., "when",
* @param args further arguments to be forwarded to the operation
* @returns result {Promise} a promise for the result of the operation
*/
Q.dispatch = dispatch;
function dispatch(object, op, args) {
return Q(object).dispatch(op, args);
}
Promise.prototype.dispatch = function (op, args) {
var self = this;
var deferred = defer();
Q.nextTick(function () {
self.promiseDispatch(deferred.resolve, op, args);
...done = function (fulfilled, rejected, progress) {
var onUnhandledError = function (error) {
// forward to a future turn so that ``when``
// does not catch it and turn it into a rejection.
Q.nextTick(function () {
makeStackTraceLong(error, promise);
if (Q.onerror) {
Q.onerror(error);
} else {
throw error;
}
});
};
// Avoid unnecessary `nextTick`ing via an unnecessary `when`.
var promise = fulfilled || rejected || progress ?
this.then(fulfilled, rejected, progress) :
this;
if (typeof process === "object" && process && process.domain) {
onUnhandledError = process.domain.bind(onUnhandledError);
}
promise.then(void 0, onUnhandledError);
}...
* calls the generator and also ends the promise chain, so that any
* unhandled errors are thrown instead of forwarded to the error
* handler. This is useful because it's extremely common to run
* generators at the top-level to work with libraries.
*/
Q.spawn = spawn;
function spawn(makeGenerator) {
Q.done(Q.async(makeGenerator)());
}
// FIXME: Remove this interface once ES6 generators are in SpiderMonkey.
/**
* Throws a ReturnValue exception to stop an asynchronous generator.
*
* This interface is a stop-gap measure to support generator return
...fail = function (rejected) {
return this.then(void 0, rejected);
}...
return Q(callback).nfapply(args);
};
Promise.prototype.nfapply = function (args) {
var deferred = defer();
var nodeArgs = array_slice(args);
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
...fapply = function (args) {
return this.dispatch("apply", [void 0, args]);
}...
return Q(callback).nfapply(args);
};
Promise.prototype.nfapply = function (args) {
var deferred = defer();
var nodeArgs = array_slice(args);
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
...fbind = function () {
var promise = this;
var args = array_slice(arguments);
return function fbound() {
return promise.dispatch("apply", [
this,
args.concat(array_slice(arguments))
]);
};
}n/a
fcall = function () {
return this.dispatch("apply", [void 0, array_slice(arguments)]);
}...
* .tap(console.log)
* .then(...);
*/
Promise.prototype.tap = function (callback) {
callback = Q(callback);
return this.then(function (value) {
return callback.fcall(value).thenResolve(value);
});
};
/**
* Registers an observer on a promise.
*
* Guarantees:
...fin = function (callback) {
if (!callback || typeof callback.apply !== "function") {
throw new Error("Q can't apply finally callback");
}
callback = Q(callback);
return this.then(function (value) {
return callback.fcall().then(function () {
return value;
});
}, function (reason) {
// TODO attempt to recycle the rejection with "this".
return callback.fcall().then(function () {
throw reason;
});
});
}...
returned by ``getInputPromise()`` either returns a value or throws an
error. The value returned or error thrown by ``getInputPromise()``
passes directly to ``outputPromise`` unless the final handler fails, and
may be delayed if the final handler returns a promise.
```javascript
var outputPromise = getInputPromise()
.fin(function () {
// close files, database connections, stop servers, conclude tests
});
```
- If the handler returns a value, the value is ignored
- If the handler throws an error, the error passes to ``outputPromise``
- If the handler returns a promise, ``outputPromise`` gets postponed. The
...finally = function (callback) {
if (!callback || typeof callback.apply !== "function") {
throw new Error("Q can't apply finally callback");
}
callback = Q(callback);
return this.then(function (value) {
return callback.fcall().then(function () {
return value;
});
}, function (reason) {
// TODO attempt to recycle the rejection with "this".
return callback.fcall().then(function () {
throw reason;
});
});
}n/a
get = function (key) {
return this.dispatch("get", [key]);
}...
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
term ``def`` was too confusing to new users.
- WARNING: ``spy`` removed in favor of ``fin``.
- WARNING: ``wait`` removed. Do ``all(args).get(0)`` instead.
- WARNING: ``join`` removed. Do ``all(args).spread(callback)`` instead.
- WARNING: Removed the ``Q`` function module.exports alias
for ``Q.ref``. It conflicts with ``Q.apply`` in weird
ways, making it uncallable.
- Revised ``delay`` so that it accepts both ``(value,
timeout)`` and ``(timeout)`` variations based on
arguments length.
...invoke = function (name) {
return this.dispatch("post", [name, array_slice(arguments, 1)]);
}...
```
If there is any chance that the promise you receive is not a Q promise
as provided by your library, you should wrap it using a Q function.
You can even use ``Q.invoke`` as a shorthand.
```javascript
return Q.invoke($, 'ajax', ...)
.then(function () {
});
```
### Over the Wire
...isFulfilled = function () {
return this.inspect().state === "fulfilled";
}n/a
isPending = function () {
return this.inspect().state === "pending";
}n/a
isRejected = function () {
return this.inspect().state === "rejected";
}n/a
join = function (that) {
return Q([this, that]).spread(function (x, y) {
if (x === y) {
// TODO: "===" should be Object.is or equiv
return x;
} else {
throw new Error("Q can't join: not the same: " + x + " " + y);
}
});
}...
if (p.stack && (!error.__minimumStackCounter__ || error.__minimumStackCounter__ > p.stackCounter)) {
object_defineProperty(error, "__minimumStackCounter__", {value: p.stackCounter, configurable: true});
stacks.unshift(p.stack);
}
}
stacks.unshift(error.stack);
var concatedStacks = stacks.join("\n" + STACK_JUMP_SEPARATOR + "\n
");
var stack = filterStackString(concatedStacks);
object_defineProperty(error, "stack", {value: stack, configurable: true});
}
}
function filterStackString(stackString) {
var lines = stackString.split("\n");
...keys = function () {
return this.dispatch("keys", []);
}n/a
mapply = function (name, args) {
return this.dispatch("post", [name, args]);
}n/a
mcall = function (name) {
return this.dispatch("post", [name, array_slice(arguments, 1)]);
}n/a
nbind = function () {
var args = array_slice(arguments, 0);
args.unshift(this);
return Q.nbind.apply(void 0, args);
}...
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
return readFile("foo.txt", "utf-8");
var redisClientGet = Q.nbind(redisClient.get, redisClient);
return redisClientGet("user:1:id");
```
Finally, if you're working with raw deferred objects, there is a
`makeNodeResolver` method on deferreds that can be handy:
```javascript
...nfapply = function (args) {
var deferred = defer();
var nodeArgs = array_slice(args);
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
}...
});
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided as an array, and returns a promise.
*
* Q.nfapply(FS.readFile, [__filename])
* .then(function (content) {
* })
*
*/
Q.nfapply = function (callback, args) {
return Q(callback).nfapply(args);
};
...nfbind = function () {
var args = array_slice(arguments);
args.unshift(this);
return Q.denodeify.apply(void 0, args);
}...
return deferred.promise;
};
/**
* Wraps a NodeJS continuation passing function and returns an equivalent
* version that returns a promise.
* @example
* Q.nfbind(FS.readFile, __filename)("utf-8")
* .then(console.log)
* .done()
*/
Q.nfbind =
Q.denodeify = function (callback /*...args*/) {
if (callback === undefined) {
throw new Error("Q can't wrap an undefined function");
...nfcall = function () {
var nodeArgs = array_slice(arguments);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
}...
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
* Q.nfcall(FS.readFile, __filename)
* .then(function (content) {
* })
*
*/
Q.nfcall = function (callback /*...args*/) {
var args = array_slice(arguments, 1);
return Q(callback).nfapply(args);
...ninvoke = function (name) {
var nodeArgs = array_slice(arguments, 1);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
this.dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}...
If you are working with methods, instead of simple functions, you can easily
run in to the usual problems where passing a method to another function—like
`Q.nfcall`—"un-binds" the method from its owner. To avoid this, you can either
use `Function.prototype.bind` or some nice shortcut methods we provide:
```javascript
return Q.ninvoke(redisClient, "get", "user:1:id");
return Q.npost(redisClient, "get", ["user:1:id"]);
```
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
...nmapply = function (name, args) {
var nodeArgs = array_slice(args || []);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
this.dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}n/a
nmcall = function (name) {
var nodeArgs = array_slice(arguments, 1);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
this.dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}n/a
nodeify = function (nodeback) {
if (nodeback) {
this.then(function (value) {
Q.nextTick(function () {
nodeback(null, value);
});
}, function (error) {
Q.nextTick(function () {
nodeback(error);
});
});
} else {
return this;
}
}...
* pass a nodeback, they will receive the result promise.
* @param object a result (or a promise for a result)
* @param {Function} nodeback a Node.js-style callback
* @returns either the promise or nothing
*/
Q.nodeify = nodeify;
function nodeify(object, nodeback) {
return Q(object).nodeify(nodeback);
}
Promise.prototype.nodeify = function (nodeback) {
if (nodeback) {
this.then(function (value) {
Q.nextTick(function () {
nodeback(null, value);
...npost = function (name, args) {
var nodeArgs = array_slice(args || []);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
this.dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}...
* @param {String} name name of the method of object
* @param {Array} args arguments to pass to the method; the callback
* will be provided by Q and appended to these arguments.
* @returns a promise for the value or error
*/
Q.nmapply = // XXX As proposed by "Redsandro"
Q.npost = function (object, name, args) {
return Q(object).npost(name, args);
};
Promise.prototype.nmapply = // XXX As proposed by "Redsandro"
Promise.prototype.npost = function (name, args) {
var nodeArgs = array_slice(args || []);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
...nsend = function (name) {
var nodeArgs = array_slice(arguments, 1);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
this.dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}n/a
passByCopy = function () {
//freeze(object);
//passByCopies.set(object, true);
return this;
}n/a
post = function (name, args) {
return this.dispatch("post", [name, args]);
}...
```
direct manipulation using a promise as a proxy
-------------------------- -------------------------------
value.foo promise.get("foo")
value.foo = value promise.put("foo", value)
delete value.foo promise.del("foo")
value.foo(...args) promise.post("foo", [args])
value.foo(...args) promise.invoke("foo", ...args)
value(...args) promise.fapply([args])
value(...args) promise.fcall(...args)
```
If the promise is a proxy for a remote object, you can shave
round-trips by using these functions instead of ``then``. To take
...progress = function (progressed) {
return this.then(void 0, void 0, progressed);
}...
promise.
## 0.8.9
- Added ``nend``
- Added preliminary progress notification support, via
``promise.then(onFulfilled, onRejected, onProgress)``,
``promise.progress(onProgress)``, and ``deferred.notify(...progressData)``.
- Made ``put`` and ``del`` return the object acted upon for easier chaining.
#84
- Fixed coercion cycles with cooperating promises. #106
## 0.8.7
- Support [Montage Require](http://github.com/kriskowal/mr)
...race = function () {
return this.then(Q.race);
}n/a
send = function (name) {
return this.dispatch("post", [name, array_slice(arguments, 1)]);
}...
var request = new XMLHttpRequest();
var deferred = Q.defer();
request.open("GET", url, true);
request.onload = onload;
request.onerror = onerror;
request.onprogress = onprogress;
request.send();
function onload() {
if (request.status === 200) {
deferred.resolve(request.responseText);
} else {
deferred.reject(new Error("Status code was " + request.status));
}
...set = function (key, value) {
return this.dispatch("set", [key, value]);
}...
promise.resolve = Q; // ES6
// XXX experimental. This method is a way to denote that a local value is
// serializable and should be immediately dispatched to a remote upon request,
// instead of passing a reference.
Q.passByCopy = function (object) {
//freeze(object);
//passByCopies.set(object, true);
return object;
};
Promise.prototype.passByCopy = function () {
//freeze(object);
//passByCopies.set(object, true);
return this;
...spread = function (fulfilled, rejected) {
return this.all().then(function (array) {
return fulfilled.apply(void 0, array);
}, rejected);
}...
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
term ``def`` was too confusing to new users.
- WARNING: ``spy`` removed in favor of ``fin``.
- WARNING: ``wait`` removed. Do ``all(args).get(0)`` instead.
- WARNING: ``join`` removed. Do ``all(args).spread(callback)`` instead.
- WARNING: Removed the ``Q`` function module.exports alias
for ``Q.ref``. It conflicts with ``Q.apply`` in weird
ways, making it uncallable.
- Revised ``delay`` so that it accepts both ``(value,
timeout)`` and ``(timeout)`` variations based on
arguments length.
- Added ``ref().spread(cb(...args))``, a variant of
...tap = function (callback) {
callback = Q(callback);
return this.then(function (value) {
return callback.fcall(value).thenResolve(value);
});
}...
}
}]);
return deferred.promise;
};
Q.tap = function (promise, callback) {
return Q(promise).tap(callback);
};
/**
* Works almost like "finally", but not called for rejections.
* Original resolution value is passed through callback unaffected.
* Callback may return a promise that will be awaited for.
* @param {Function} callback
...then = function (fulfilled, rejected, progressed) {
var self = this;
var deferred = defer();
var done = false; // ensure the untrusted promise makes at most a
// single call to one of the callbacks
function _fulfilled(value) {
try {
return typeof fulfilled === "function" ? fulfilled(value) : value;
} catch (exception) {
return reject(exception);
}
}
function _rejected(exception) {
if (typeof rejected === "function") {
makeStackTraceLong(exception, self);
try {
return rejected(exception);
} catch (newException) {
return reject(newException);
}
}
return reject(exception);
}
function _progressed(value) {
return typeof progressed === "function" ? progressed(value) : value;
}
Q.nextTick(function () {
self.promiseDispatch(function (value) {
if (done) {
return;
}
done = true;
deferred.resolve(_fulfilled(value));
}, "when", [function (exception) {
if (done) {
return;
}
done = true;
deferred.resolve(_rejected(exception));
}]);
});
// Progress propagator need to be attached in the current tick.
self.promiseDispatch(void 0, "when", [void 0, function (value) {
var newValue;
var threw = false;
try {
newValue = _progressed(value);
} catch (e) {
threw = true;
if (Q.onerror) {
Q.onerror(e);
} else {
throw e;
}
}
if (!threw) {
deferred.notify(newValue);
}
}]);
return deferred.promise;
}...
- Fixed ``spread`` not calling the passed rejection handler if given a rejected
promise.
## 0.8.9
- Added ``nend``
- Added preliminary progress notification support, via
``promise.then(onFulfilled, onRejected, onProgress)``,
``promise.progress(onProgress)``, and ``deferred.notify(...progressData)``.
- Made ``put`` and ``del`` return the object acted upon for easier chaining.
#84
- Fixed coercion cycles with cooperating promises. #106
## 0.8.7
...thenReject = function (reason) {
return this.then(function () { throw reason; });
}...
};
Promise.prototype.thenReject = function (reason) {
return this.then(function () { throw reason; });
};
Q.thenReject = function (promise, reason) {
return Q(promise).thenReject(reason);
};
/**
* If an object is not a promise, it is as "near" as possible.
* If a promise is rejected, it is as "near" as possible too.
* If it’s a fulfilled promise, the fulfillment value is nearer.
* If it’s a deferred promise and the deferred has been resolved, the
...thenResolve = function (value) {
return this.then(function () { return value; });
}...
* .tap(console.log)
* .then(...);
*/
Promise.prototype.tap = function (callback) {
callback = Q(callback);
return this.then(function (value) {
return callback.fcall(value).thenResolve(value);
});
};
/**
* Registers an observer on a promise.
*
* Guarantees:
...timeout = function (ms, error) {
var deferred = defer();
var timeoutId = setTimeout(function () {
if (!error || "string" === typeof error) {
error = new Error(error || "Timed out after " + ms + " ms");
error.code = "ETIMEDOUT";
}
deferred.reject(error);
}, ms);
this.then(function (value) {
clearTimeout(timeoutId);
deferred.resolve(value);
}, function (exception) {
clearTimeout(timeoutId);
deferred.reject(exception);
}, deferred.notify);
return deferred.promise;
}...
* @param {Any*} promise
* @param {Number} milliseconds timeout
* @param {Any*} custom error message or Error object (optional)
* @returns a promise for the resolution of the given promise if it is
* fulfilled before the timeout, otherwise rejected.
*/
Q.timeout = function (object, ms, error) {
return Q(object).timeout(ms, error);
};
Promise.prototype.timeout = function (ms, error) {
var deferred = defer();
var timeoutId = setTimeout(function () {
if (!error || "string" === typeof error) {
error = new Error(error || "Timed out after " + ms + " ms");
...toString = function () {
return "[object Promise]";
}...
if (!flushing) {
flushing = true;
requestTick();
}
};
if (typeof process === "object" &&
process.toString() === "[object process]" && process.nextTick
) {
// Ensure Q is in a real Node environment, with a `process.nextTick`.
// To see through fake Node environments:
// * Mocha test runner - exposes a `process` global without a `nextTick`
// * Browserify - exposes a `process.nexTick` function that uses
// `setTimeout`. In this case `setImmediate` is preferred because
// it is faster. Browserify's `process.toString()` yields
// "[object Object]", while in a real Node environment
...nextTick = function (task) {
tail = tail.next = {
task: task,
domain: isNodeJS && process.domain,
next: null
};
if (!flushing) {
flushing = true;
requestTick();
}
}...
// `setTimeout`. In this case `setImmediate` is preferred because
// it is faster. Browserify's `process.toString()` yields
// "[object Object]", while in a real Node environment
// `process.toString()` yields "[object process]".
isNodeJS = true;
requestTick = function () {
process.nextTick(flush);
};
} else if (typeof setImmediate === "function") {
// In IE10, Node.js 0.9+, or https://github.com/NobleJS/setImmediate
if (typeof window !== "undefined") {
requestTick = setImmediate.bind(window, flush);
} else {
...runAfter = function (task) {
laterQueue.push(task);
if (!flushing) {
flushing = true;
requestTick();
}
}...
}
function trackRejection(promise, reason) {
if (!trackUnhandledRejections) {
return;
}
if (typeof process === "object" && typeof process.emit === "function") {
Q.nextTick.runAfter(function () {
if (array_indexOf(unhandledRejections, promise) !== -1) {
process.emit("unhandledRejection", reason, promise);
reportedUnhandledRejections.push(promise);
}
});
}
...function Q(value) {
// If the object is already a Promise, return it directly. This enables
// the resolve function to both be used to created references from objects,
// but to tolerably coerce non-promises to promises.
if (value instanceof Promise) {
return value;
}
// assimilate thenables
if (isPromiseAlike(value)) {
return coerce(value);
} else {
return fulfill(value);
}
}...
*/
defer.prototype.makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
};
/**
...function promise(resolver) {
if (typeof resolver !== "function") {
throw new TypeError("resolver must be a function.");
}
var deferred = defer();
try {
resolver(deferred.resolve, deferred.reject, deferred.notify);
} catch (reason) {
deferred.reject(reason);
}
return deferred.promise;
}...
This is an alternative promise-creation API that has the same power as
the deferred concept, but without introducing another conceptual entity.
Rewriting the `requestOkText` example above using `Q.Promise`:
```javascript
function requestOkText(url) {
return Q.Promise(function(resolve, reject, notify) {
var request = new XMLHttpRequest();
request.open("GET", url, true);
request.onload = onload;
request.onerror = onerror;
request.onprogress = onprogress;
request.send();
...function all(promises) {
return when(promises, function (promises) {
var pendingCount = 0;
var deferred = defer();
array_reduce(promises, function (undefined, promise, index) {
var snapshot;
if (
isPromise(promise) &&
(snapshot = promise.inspect()).state === "fulfilled"
) {
promises[index] = snapshot.value;
} else {
++pendingCount;
when(
promise,
function (value) {
promises[index] = value;
if (--pendingCount === 0) {
deferred.resolve(promises);
}
},
deferred.reject,
function (progress) {
deferred.notify({ index: index, value: progress });
}
);
}
}, void 0);
if (pendingCount === 0) {
deferred.resolve(promises);
}
return deferred.promise;
});
}...
- Deprecated ``ref`` in favor of ``resolve`` as recommended by
@domenic.
- Update event-queue dependency.
## 0.8.1
- Fixed Opera bug. #35 @cadorn
- Fixed ``Q.all([])`` #32 @domenic
## 0.8.0
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
...allResolved = function () {
if (typeof console !== "undefined" &&
typeof console.warn === "function") {
console.warn(name + " is deprecated, use " + alternative +
" instead.", new Error("").stack);
}
return callback.apply(callback, arguments);
}n/a
function allSettled(promises) {
return Q(promises).allSettled();
}...
};
/**
* @see Promise#allSettled
*/
Q.allSettled = allSettled;
function allSettled(promises) {
return Q(promises).allSettled();
}
/**
* Turns an array of promises into a promise for an array of their states (as
* returned by `inspect`) when they have all settled.
* @param {Array[Any*]} values an array (or promise for an array) of values (or
* promises for values)
...function any(promises) {
if (promises.length === 0) {
return Q.resolve();
}
var deferred = Q.defer();
var pendingCount = 0;
array_reduce(promises, function (prev, current, index) {
var promise = promises[index];
pendingCount++;
when(promise, onFulfilled, onRejected, onProgress);
function onFulfilled(result) {
deferred.resolve(result);
}
function onRejected(err) {
pendingCount--;
if (pendingCount === 0) {
err.message = ("Q can't get fulfillment value from any promise, all " +
"promises were rejected. Last error message: " + err.message);
deferred.reject(err);
}
}
function onProgress(progress) {
deferred.notify({
index: index,
value: progress
});
}
}, undefined);
return deferred.promise;
}...
## 1.2.1
- Fix Node.js environment detection for modern Browserify (@kahnjw).
## 1.2.0
- Added Q.any(promisesArray) method (@vergara).
Returns a promise fulfilled with the value of the first resolved promise in
promisesArray. If all promises in promisesArray are rejected, it returns
a rejected promise.
## 1.1.2
- Removed extraneous files from the npm package by using the "files"
...function async(makeGenerator) {
return function () {
// when verb is "send", arg is a value
// when verb is "throw", arg is an exception
function continuer(verb, arg) {
var result;
// Until V8 3.19 / Chromium 29 is released, SpiderMonkey is the only
// engine that has a deployed base of browsers that support generators.
// However, SM's generators use the Python-inspired semantics of
// outdated ES6 drafts. We would like to support ES6, but we'd also
// like to make it possible to use generators in deployed browsers, so
// we also support Python-style generators. At some point we can remove
// this block.
if (typeof StopIteration === "undefined") {
// ES6 Generators
try {
result = generator[verb](arg);
} catch (exception) {
return reject(exception);
}
if (result.done) {
return Q(result.value);
} else {
return when(result.value, callback, errback);
}
} else {
// SpiderMonkey Generators
// FIXME: Remove this case when SM does ES6 generators.
try {
result = generator[verb](arg);
} catch (exception) {
if (isStopIteration(exception)) {
return Q(exception.value);
} else {
return reject(exception);
}
}
return when(result, callback, errback);
}
}
var generator = makeGenerator.apply(this, arguments);
var callback = continuer.bind(continuer, "next");
var errback = continuer.bind(continuer, "throw");
return callback();
};
}...
* calls the generator and also ends the promise chain, so that any
* unhandled errors are thrown instead of forwarded to the error
* handler. This is useful because it's extremely common to run
* generators at the top-level to work with libraries.
*/
Q.spawn = spawn;
function spawn(makeGenerator) {
Q.done(Q.async(makeGenerator)());
}
// FIXME: Remove this interface once ES6 generators are in SpiderMonkey.
/**
* Throws a ReturnValue exception to stop an asynchronous generator.
*
* This interface is a stop-gap measure to support generator return
...catch = function (object, rejected) {
return Q(object).then(void 0, rejected);
}...
Q.fcall(promisedStep1)
.then(promisedStep2)
.then(promisedStep3)
.then(promisedStep4)
.then(function (value4) {
// Do something with value4
})
.catch(function (error) {
// Handle any error from all above steps
})
.done();
```
With this approach, you also get implicit error propagation, just like `try`,
`catch`, and `finally`. An error in `promisedStep1` will flow all the way to
...function defer() {
// if "messages" is an "Array", that indicates that the promise has not yet
// been resolved. If it is "undefined", it has been resolved. Each
// element of the messages array is itself an array of complete arguments to
// forward to the resolved promise. We coerce the resolution value to a
// promise using the `resolve` function because it handles both fully
// non-thenable values and other thenables gracefully.
var messages = [], progressListeners = [], resolvedPromise;
var deferred = object_create(defer.prototype);
var promise = object_create(Promise.prototype);
promise.promiseDispatch = function (resolve, op, operands) {
var args = array_slice(arguments);
if (messages) {
messages.push(args);
if (op === "when" && operands[1]) { // progress operand
progressListeners.push(operands[1]);
}
} else {
Q.nextTick(function () {
resolvedPromise.promiseDispatch.apply(resolvedPromise, args);
});
}
};
// XXX deprecated
promise.valueOf = function () {
if (messages) {
return promise;
}
var nearerValue = nearer(resolvedPromise);
if (isPromise(nearerValue)) {
resolvedPromise = nearerValue; // shorten chain
}
return nearerValue;
};
promise.inspect = function () {
if (!resolvedPromise) {
return { state: "pending" };
}
return resolvedPromise.inspect();
};
if (Q.longStackSupport && hasStacks) {
try {
throw new Error();
} catch (e) {
// NOTE: don't try to use `Error.captureStackTrace` or transfer the
// accessor around; that causes memory leaks as per GH-111. Just
// reify the stack trace as a string ASAP.
//
// At the same time, cut off the first line; it's always just
// "[object Promise]\n", as per the `toString`.
promise.stack = e.stack.substring(e.stack.indexOf("\n") + 1);
promise.stackCounter = longStackCounter++;
}
}
// NOTE: we do the checks for `resolvedPromise` in each method, instead of
// consolidating them into `become`, since otherwise we'd create new
// promises with the lines `become(whatever(value))`. See e.g. GH-252.
function become(newPromise) {
resolvedPromise = newPromise;
if (Q.longStackSupport && hasStacks) {
// Only hold a reference to the new promise if long stacks
// are enabled to reduce memory usage
promise.source = newPromise;
}
array_reduce(messages, function (undefined, message) {
Q.nextTick(function () {
newPromise.promiseDispatch.apply(newPromise, message);
});
}, void 0);
messages = void 0;
progressListeners = void 0;
}
deferred.promise = promise;
deferred.resolve = function (value) {
if (resolvedPromise) {
return;
}
become(Q(value));
};
deferred.fulfill = function (value) {
if (resolvedPromise) {
return;
}
become(fulfill(value));
};
deferred.reject = function (reason) {
if (resolvedPromise) {
return;
}
become(reject(reason));
};
deferred.notify = function (progress) {
if (resolvedPromise) {
return;
}
array_reduce(progressListeners, function (undefined, progressListener) {
Q.nextTick(function () {
progressListener(progress);
});
}, void 0);
};
return deferred;
}...
Q.any = any;
function any(promises) {
if (promises.length === 0) {
return Q.resolve();
}
var deferred = Q.defer();
var pendingCount = 0;
array_reduce(promises, function (prev, current, index) {
var promise = promises[index];
pendingCount++;
when(promise, onFulfilled, onRejected, onProgress);
...del = function (object, key) {
return Q(object).dispatch("delete", [key]);
}...
promises, so they can be chained.
```
direct manipulation using a promise as a proxy
-------------------------- -------------------------------
value.foo promise.get("foo")
value.foo = value promise.put("foo", value)
delete value.foo promise.del("foo")
value.foo(...args) promise.post("foo", [args])
value.foo(...args) promise.invoke("foo", ...args)
value(...args) promise.fapply([args])
value(...args) promise.fcall(...args)
```
If the promise is a proxy for a remote object, you can shave
...delay = function (object, timeout) {
if (timeout === void 0) {
timeout = object;
object = void 0;
}
return Q(object).delay(timeout);
}...
* If the given promise rejects, that is passed immediately.
*/
Q.delay = function (object, timeout) {
if (timeout === void 0) {
timeout = object;
object = void 0;
}
return Q(object).delay(timeout);
};
Promise.prototype.delay = function (timeout) {
return this.then(function (value) {
var deferred = defer();
setTimeout(function () {
deferred.resolve(value);
...delete = function (object, key) {
return Q(object).dispatch("delete", [key]);
}n/a
denodeify = function (callback) {
if (callback === undefined) {
throw new Error("Q can't wrap an undefined function");
}
var baseArgs = array_slice(arguments, 1);
return function () {
var nodeArgs = baseArgs.concat(array_slice(arguments));
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(callback).fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
}...
return Q.ninvoke(redisClient, "get", "user:1:id");
return Q.npost(redisClient, "get", ["user:1:id"]);
```
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
return readFile("foo.txt", "utf-8");
var redisClientGet = Q.nbind(redisClient.get, redisClient);
return redisClientGet("user:1:id");
```
Finally, if you're working with raw deferred objects, there is a
...function dispatch(object, op, args) {
return Q(object).dispatch(op, args);
}...
* @param object* the recipient
* @param op the name of the message operation, e.g., "when",
* @param args further arguments to be forwarded to the operation
* @returns result {Promise} a promise for the result of the operation
*/
Q.dispatch = dispatch;
function dispatch(object, op, args) {
return Q(object).dispatch(op, args);
}
Promise.prototype.dispatch = function (op, args) {
var self = this;
var deferred = defer();
Q.nextTick(function () {
self.promiseDispatch(deferred.resolve, op, args);
...done = function (object, fulfilled, rejected, progress) {
return Q(object).done(fulfilled, rejected, progress);
}...
* calls the generator and also ends the promise chain, so that any
* unhandled errors are thrown instead of forwarded to the error
* handler. This is useful because it's extremely common to run
* generators at the top-level to work with libraries.
*/
Q.spawn = spawn;
function spawn(makeGenerator) {
Q.done(Q.async(makeGenerator)());
}
// FIXME: Remove this interface once ES6 generators are in SpiderMonkey.
/**
* Throws a ReturnValue exception to stop an asynchronous generator.
*
* This interface is a stop-gap measure to support generator return
...fail = function (object, rejected) {
return Q(object).then(void 0, rejected);
}...
return Q(callback).nfapply(args);
};
Promise.prototype.nfapply = function (args) {
var deferred = defer();
var nodeArgs = array_slice(args);
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
...fapply = function (object, args) {
return Q(object).dispatch("apply", [void 0, args]);
}...
return Q(callback).nfapply(args);
};
Promise.prototype.nfapply = function (args) {
var deferred = defer();
var nodeArgs = array_slice(args);
nodeArgs.push(deferred.makeNodeResolver());
this.fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
...fbind = function (object) {
var promise = Q(object);
var args = array_slice(arguments, 1);
return function fbound() {
return promise.dispatch("apply", [
this,
args.concat(array_slice(arguments))
]);
};
}n/a
fcall = function (object) {
return Q(object).dispatch("apply", [void 0, array_slice(arguments, 1)]);
}...
* .tap(console.log)
* .then(...);
*/
Promise.prototype.tap = function (callback) {
callback = Q(callback);
return this.then(function (value) {
return callback.fcall(value).thenResolve(value);
});
};
/**
* Registers an observer on a promise.
*
* Guarantees:
...fin = function (object, callback) {
return Q(object)["finally"](callback);
}...
returned by ``getInputPromise()`` either returns a value or throws an
error. The value returned or error thrown by ``getInputPromise()``
passes directly to ``outputPromise`` unless the final handler fails, and
may be delayed if the final handler returns a promise.
```javascript
var outputPromise = getInputPromise()
.fin(function () {
// close files, database connections, stop servers, conclude tests
});
```
- If the handler returns a value, the value is ignored
- If the handler throws an error, the error passes to ``outputPromise``
- If the handler returns a promise, ``outputPromise`` gets postponed. The
...finally = function (object, callback) {
return Q(object)["finally"](callback);
}n/a
function fulfill(value) {
return Promise({
"when": function () {
return value;
},
"get": function (name) {
return value[name];
},
"set": function (name, rhs) {
value[name] = rhs;
},
"delete": function (name) {
delete value[name];
},
"post": function (name, args) {
// Mark Miller proposes that post with no name should apply a
// promised function.
if (name === null || name === void 0) {
return value.apply(void 0, args);
} else {
return value[name].apply(value, args);
}
},
"apply": function (thisp, args) {
return value.apply(thisp, args);
},
"keys": function () {
return object_keys(value);
}
}, void 0, function inspect() {
return { state: "fulfilled", value: value };
});
}n/a
get = function (object, key) {
return Q(object).dispatch("get", [key]);
}...
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
term ``def`` was too confusing to new users.
- WARNING: ``spy`` removed in favor of ``fin``.
- WARNING: ``wait`` removed. Do ``all(args).get(0)`` instead.
- WARNING: ``join`` removed. Do ``all(args).spread(callback)`` instead.
- WARNING: Removed the ``Q`` function module.exports alias
for ``Q.ref``. It conflicts with ``Q.apply`` in weird
ways, making it uncallable.
- Revised ``delay`` so that it accepts both ``(value,
timeout)`` and ``(timeout)`` variations based on
arguments length.
...getUnhandledReasons = function () {
// Make a copy so that consumers can't interfere with our internal state.
return unhandledReasons.slice();
}n/a
invoke = function (object, name) {
return Q(object).dispatch("post", [name, array_slice(arguments, 2)]);
}...
```
If there is any chance that the promise you receive is not a Q promise
as provided by your library, you should wrap it using a Q function.
You can even use ``Q.invoke`` as a shorthand.
```javascript
return Q.invoke($, 'ajax', ...)
.then(function () {
});
```
### Over the Wire
...function isFulfilled(object) {
return !isPromise(object) || object.inspect().state === "fulfilled";
}n/a
function isPending(object) {
return isPromise(object) && object.inspect().state === "pending";
}n/a
function isPromise(object) {
return object instanceof Promise;
}n/a
function isPromiseAlike(object) {
return isObject(object) && typeof object.then === "function";
}n/a
function isRejected(object) {
return isPromise(object) && object.inspect().state === "rejected";
}n/a
join = function (x, y) {
return Q(x).join(y);
}...
if (p.stack && (!error.__minimumStackCounter__ || error.__minimumStackCounter__ > p.stackCounter)) {
object_defineProperty(error, "__minimumStackCounter__", {value: p.stackCounter, configurable: true});
stacks.unshift(p.stack);
}
}
stacks.unshift(error.stack);
var concatedStacks = stacks.join("\n" + STACK_JUMP_SEPARATOR + "\n
");
var stack = filterStackString(concatedStacks);
object_defineProperty(error, "stack", {value: stack, configurable: true});
}
}
function filterStackString(stackString) {
var lines = stackString.split("\n");
...keys = function (object) {
return Q(object).dispatch("keys", []);
}n/a
function Promise(descriptor, fallback, inspect) {
if (fallback === void 0) {
fallback = function (op) {
return reject(new Error(
"Promise does not support operation: " + op
));
};
}
if (inspect === void 0) {
inspect = function () {
return {state: "unknown"};
};
}
var promise = object_create(Promise.prototype);
promise.promiseDispatch = function (resolve, op, args) {
var result;
try {
if (descriptor[op]) {
result = descriptor[op].apply(promise, args);
} else {
result = fallback.call(promise, op, args);
}
} catch (exception) {
result = reject(exception);
}
if (resolve) {
resolve(result);
}
};
promise.inspect = inspect;
// XXX deprecated `valueOf` and `exception` support
if (inspect) {
var inspected = inspect();
if (inspected.state === "rejected") {
promise.exception = inspected.reason;
}
promise.valueOf = function () {
var inspected = inspect();
if (inspected.state === "pending" ||
inspected.state === "rejected") {
return promise;
}
return inspected.value;
};
}
return promise;
}n/a
mapply = function (object, name, args) {
return Q(object).dispatch("post", [name, args]);
}n/a
function master(object) {
return Promise({
"isDef": function () {}
}, function fallback(op, args) {
return dispatch(object, op, args);
}, function () {
return Q(object).inspect();
});
}n/a
mcall = function (object, name) {
return Q(object).dispatch("post", [name, array_slice(arguments, 2)]);
}n/a
nbind = function (callback, thisp) {
var baseArgs = array_slice(arguments, 2);
return function () {
var nodeArgs = baseArgs.concat(array_slice(arguments));
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
function bound() {
return callback.apply(thisp, arguments);
}
Q(bound).fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
}...
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
return readFile("foo.txt", "utf-8");
var redisClientGet = Q.nbind(redisClient.get, redisClient);
return redisClientGet("user:1:id");
```
Finally, if you're working with raw deferred objects, there is a
`makeNodeResolver` method on deferreds that can be handy:
```javascript
...function nearer(value) {
if (isPromise(value)) {
var inspected = value.inspect();
if (inspected.state === "fulfilled") {
return inspected.value;
}
}
return value;
}n/a
nextTick = function (task) {
tail = tail.next = {
task: task,
domain: isNodeJS && process.domain,
next: null
};
if (!flushing) {
flushing = true;
requestTick();
}
}...
// `setTimeout`. In this case `setImmediate` is preferred because
// it is faster. Browserify's `process.toString()` yields
// "[object Object]", while in a real Node environment
// `process.toString()` yields "[object process]".
isNodeJS = true;
requestTick = function () {
process.nextTick(flush);
};
} else if (typeof setImmediate === "function") {
// In IE10, Node.js 0.9+, or https://github.com/NobleJS/setImmediate
if (typeof window !== "undefined") {
requestTick = setImmediate.bind(window, flush);
} else {
...nfapply = function (callback, args) {
return Q(callback).nfapply(args);
}...
});
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided as an array, and returns a promise.
*
* Q.nfapply(FS.readFile, [__filename])
* .then(function (content) {
* })
*
*/
Q.nfapply = function (callback, args) {
return Q(callback).nfapply(args);
};
...nfbind = function (callback) {
if (callback === undefined) {
throw new Error("Q can't wrap an undefined function");
}
var baseArgs = array_slice(arguments, 1);
return function () {
var nodeArgs = baseArgs.concat(array_slice(arguments));
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(callback).fapply(nodeArgs).fail(deferred.reject);
return deferred.promise;
};
}...
return deferred.promise;
};
/**
* Wraps a NodeJS continuation passing function and returns an equivalent
* version that returns a promise.
* @example
* Q.nfbind(FS.readFile, __filename)("utf-8")
* .then(console.log)
* .done()
*/
Q.nfbind =
Q.denodeify = function (callback /*...args*/) {
if (callback === undefined) {
throw new Error("Q can't wrap an undefined function");
...nfcall = function (callback) {
var args = array_slice(arguments, 1);
return Q(callback).nfapply(args);
}...
return deferred.promise;
};
/**
* Passes a continuation to a Node function, which is called with the given
* arguments provided individually, and returns a promise.
* @example
* Q.nfcall(FS.readFile, __filename)
* .then(function (content) {
* })
*
*/
Q.nfcall = function (callback /*...args*/) {
var args = array_slice(arguments, 1);
return Q(callback).nfapply(args);
...ninvoke = function (object, name) {
var nodeArgs = array_slice(arguments, 2);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(object).dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}...
If you are working with methods, instead of simple functions, you can easily
run in to the usual problems where passing a method to another function—like
`Q.nfcall`—"un-binds" the method from its owner. To avoid this, you can either
use `Function.prototype.bind` or some nice shortcut methods we provide:
```javascript
return Q.ninvoke(redisClient, "get", "user:1:id");
return Q.npost(redisClient, "get", ["user:1:id"]);
```
You can also create reusable wrappers with `Q.denodeify` or `Q.nbind`:
```javascript
var readFile = Q.denodeify(FS.readFile);
...nmapply = function (object, name, args) {
return Q(object).npost(name, args);
}n/a
nmcall = function (object, name) {
var nodeArgs = array_slice(arguments, 2);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(object).dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}n/a
noConflict = function () {
throw new Error("Q.noConflict only works when Q is used as a global");
}n/a
function nodeify(object, nodeback) {
return Q(object).nodeify(nodeback);
}...
* pass a nodeback, they will receive the result promise.
* @param object a result (or a promise for a result)
* @param {Function} nodeback a Node.js-style callback
* @returns either the promise or nothing
*/
Q.nodeify = nodeify;
function nodeify(object, nodeback) {
return Q(object).nodeify(nodeback);
}
Promise.prototype.nodeify = function (nodeback) {
if (nodeback) {
this.then(function (value) {
Q.nextTick(function () {
nodeback(null, value);
...npost = function (object, name, args) {
return Q(object).npost(name, args);
}...
* @param {String} name name of the method of object
* @param {Array} args arguments to pass to the method; the callback
* will be provided by Q and appended to these arguments.
* @returns a promise for the value or error
*/
Q.nmapply = // XXX As proposed by "Redsandro"
Q.npost = function (object, name, args) {
return Q(object).npost(name, args);
};
Promise.prototype.nmapply = // XXX As proposed by "Redsandro"
Promise.prototype.npost = function (name, args) {
var nodeArgs = array_slice(args || []);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
...nsend = function (object, name) {
var nodeArgs = array_slice(arguments, 2);
var deferred = defer();
nodeArgs.push(deferred.makeNodeResolver());
Q(object).dispatch("post", [name, nodeArgs]).fail(deferred.reject);
return deferred.promise;
}n/a
passByCopy = function (object) {
//freeze(object);
//passByCopies.set(object, true);
return object;
}n/a
post = function (object, name, args) {
return Q(object).dispatch("post", [name, args]);
}...
```
direct manipulation using a promise as a proxy
-------------------------- -------------------------------
value.foo promise.get("foo")
value.foo = value promise.put("foo", value)
delete value.foo promise.del("foo")
value.foo(...args) promise.post("foo", [args])
value.foo(...args) promise.invoke("foo", ...args)
value(...args) promise.fapply([args])
value(...args) promise.fcall(...args)
```
If the promise is a proxy for a remote object, you can shave
round-trips by using these functions instead of ``then``. To take
...function progress(object, progressed) {
return Q(object).then(void 0, void 0, progressed);
}...
promise.
## 0.8.9
- Added ``nend``
- Added preliminary progress notification support, via
``promise.then(onFulfilled, onRejected, onProgress)``,
``promise.progress(onProgress)``, and ``deferred.notify(...progressData)``.
- Made ``put`` and ``del`` return the object acted upon for easier chaining.
#84
- Fixed coercion cycles with cooperating promises. #106
## 0.8.7
- Support [Montage Require](http://github.com/kriskowal/mr)
...function promise(resolver) {
if (typeof resolver !== "function") {
throw new TypeError("resolver must be a function.");
}
var deferred = defer();
try {
resolver(deferred.resolve, deferred.reject, deferred.notify);
} catch (reason) {
deferred.reject(reason);
}
return deferred.promise;
}...
and the message now includes the duration of the timeout in
miliseconds. This doesn't constitute (in my opinion) a
backward-incompatibility since it is a change of an undocumented and
unspecified public behavior, but if you happened to depend on the
exception being a string, you will need to revise your code.
- Added ``deferred.makeNodeResolver()`` to replace the more cryptic
``deferred.node()`` method.
- Added experimental ``Q.promise(maker(resolve, reject))`` to make a
promise inside a callback, such that thrown exceptions in the
callback are converted and the resolver and rejecter are arguments.
This is a shorthand for making a deferred directly and inspired by
@gozala’s stream constructor pattern and the Microsoft Windows Metro
Promise constructor interface.
- Added experimental ``Q.begin()`` that is intended to kick off chains
of ``.then`` so that each of these can be reordered without having to
...function promised(callback) {
return function () {
return spread([this, all(arguments)], function (self, args) {
return callback.apply(self, args);
});
};
}...
/**
* The promised function decorator ensures that any promise arguments
* are settled and passed as values (`this` is also settled and passed
* as a value). It will also ensure that the result of a function is
* always a promise.
*
* @example
* var add = Q.promised(function (a, b) {
* return a + b;
* });
* add(Q(a), Q(B));
*
* @param {function} callback The function to decorate
* @returns {function} a function that has been decorated.
*/
...function race(answerPs) {
return promise(function (resolve, reject) {
// Switch to this once we can assume at least ES5
// answerPs.forEach(function (answerP) {
// Q(answerP).then(resolve, reject);
// });
// Use this in the meantime
for (var i = 0, len = answerPs.length; i < len; i++) {
Q(answerPs[i]).then(resolve, reject);
}
});
}n/a
function reject(reason) {
var rejection = Promise({
"when": function (rejected) {
// note that the error has been handled
if (rejected) {
untrackRejection(this);
}
return rejected ? rejected(reason) : this;
}
}, function fallback() {
return this;
}, function inspect() {
return { state: "rejected", reason: reason };
});
// Note that the reason has not been handled.
trackRejection(rejection, reason);
return rejection;
}...
* promise.
* @returns a nodeback
*/
defer.prototype.makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
};
...function resetUnhandledRejections() {
unhandledReasons.length = 0;
unhandledRejections.length = 0;
if (!trackUnhandledRejections) {
trackUnhandledRejections = true;
}
}n/a
function _return(value) {
throw new QReturnValue(value);
}...
* var bar = yield getBarPromise();
* return foo + bar;
* })
* // Older SpiderMonkey style
* Q.async(function () {
* var foo = yield getFooPromise();
* var bar = yield getBarPromise();
* Q.return(foo + bar);
* })
*/
Q["return"] = _return;
function _return(value) {
throw new QReturnValue(value);
}
...send = function (object, name) {
return Q(object).dispatch("post", [name, array_slice(arguments, 2)]);
}...
var request = new XMLHttpRequest();
var deferred = Q.defer();
request.open("GET", url, true);
request.onload = onload;
request.onerror = onerror;
request.onprogress = onprogress;
request.send();
function onload() {
if (request.status === 200) {
deferred.resolve(request.responseText);
} else {
deferred.reject(new Error("Status code was " + request.status));
}
...set = function (object, key, value) {
return Q(object).dispatch("set", [key, value]);
}...
promise.resolve = Q; // ES6
// XXX experimental. This method is a way to denote that a local value is
// serializable and should be immediately dispatched to a remote upon request,
// instead of passing a reference.
Q.passByCopy = function (object) {
//freeze(object);
//passByCopies.set(object, true);
return object;
};
Promise.prototype.passByCopy = function () {
//freeze(object);
//passByCopies.set(object, true);
return this;
...function spawn(makeGenerator) {
Q.done(Q.async(makeGenerator)());
}n/a
function spread(value, fulfilled, rejected) {
return Q(value).spread(fulfilled, rejected);
}...
- WARNING: ``enqueue`` removed. Use ``nextTick`` instead.
This is more consistent with NodeJS and (subjectively)
more explicit and intuitive.
- WARNING: ``def`` removed. Use ``master`` instead. The
term ``def`` was too confusing to new users.
- WARNING: ``spy`` removed in favor of ``fin``.
- WARNING: ``wait`` removed. Do ``all(args).get(0)`` instead.
- WARNING: ``join`` removed. Do ``all(args).spread(callback)`` instead.
- WARNING: Removed the ``Q`` function module.exports alias
for ``Q.ref``. It conflicts with ``Q.apply`` in weird
ways, making it uncallable.
- Revised ``delay`` so that it accepts both ``(value,
timeout)`` and ``(timeout)`` variations based on
arguments length.
- Added ``ref().spread(cb(...args))``, a variant of
...stopUnhandledRejectionTracking = function () {
resetUnhandledRejections();
trackUnhandledRejections = false;
}n/a
tap = function (promise, callback) {
return Q(promise).tap(callback);
}...
}
}]);
return deferred.promise;
};
Q.tap = function (promise, callback) {
return Q(promise).tap(callback);
};
/**
* Works almost like "finally", but not called for rejections.
* Original resolution value is passed through callback unaffected.
* Callback may return a promise that will be awaited for.
* @param {Function} callback
...thenReject = function (promise, reason) {
return Q(promise).thenReject(reason);
}...
};
Promise.prototype.thenReject = function (reason) {
return this.then(function () { throw reason; });
};
Q.thenReject = function (promise, reason) {
return Q(promise).thenReject(reason);
};
/**
* If an object is not a promise, it is as "near" as possible.
* If a promise is rejected, it is as "near" as possible too.
* If it’s a fulfilled promise, the fulfillment value is nearer.
* If it’s a deferred promise and the deferred has been resolved, the
...thenResolve = function (promise, value) {
return Q(promise).thenResolve(value);
}...
* .tap(console.log)
* .then(...);
*/
Promise.prototype.tap = function (callback) {
callback = Q(callback);
return this.then(function (value) {
return callback.fcall(value).thenResolve(value);
});
};
/**
* Registers an observer on a promise.
*
* Guarantees:
...timeout = function (object, ms, error) {
return Q(object).timeout(ms, error);
}...
* @param {Any*} promise
* @param {Number} milliseconds timeout
* @param {Any*} custom error message or Error object (optional)
* @returns a promise for the resolution of the given promise if it is
* fulfilled before the timeout, otherwise rejected.
*/
Q.timeout = function (object, ms, error) {
return Q(object).timeout(ms, error);
};
Promise.prototype.timeout = function (ms, error) {
var deferred = defer();
var timeoutId = setTimeout(function () {
if (!error || "string" === typeof error) {
error = new Error(error || "Timed out after " + ms + " ms");
...try = function (object) {
return Q(object).dispatch("apply", [void 0, array_slice(arguments, 1)]);
}n/a
function when(value, fulfilled, rejected, progressed) {
return Q(value).then(fulfilled, rejected, progressed);
}...
```
This is a simplified implementation of ``Q.timeout``
```javascript
function timeout(promise, ms) {
var deferred = Q.defer();
Q.when(promise, deferred.resolve);
delay(ms).then(function () {
deferred.reject(new Error("Timed out"));
});
return deferred.promise;
}
```
...