function seedrandom(seed, options, callback) {
var key = [];
options = (options == true) ? { entropy: true } : (options || {});
// Flatten the seed string or build one from local entropy if needed.
var shortseed = mixkey(flatten(
options.entropy ? [seed, tostring(pool)] :
(seed == null) ? autoseed() : seed, 3), key);
// Use the seed to initialize an ARC4 generator.
var arc4 = new ARC4(key);
// This function returns a random double in [0, 1) that contains
// randomness in every bit of the mantissa of the IEEE 754 value.
var prng = function() {
var n = arc4.g(chunks), // Start with a numerator n < 2 ^ 48
d = startdenom, // and denominator d = 2 ^ 48.
x = 0; // and no 'extra last byte'.
while (n < significance) { // Fill up all significant digits by
n = (n + x) * width; // shifting numerator and
d *= width; // denominator and generating a
x = arc4.g(1); // new least-significant-byte.
}
while (n >= overflow) { // To avoid rounding up, before adding
n /= 2; // last byte, shift everything
d /= 2; // right using integer math until
x >>>= 1; // we have exactly the desired bits.
}
return (n + x) / d; // Form the number within [0, 1).
};
prng.int32 = function() { return arc4.g(4) | 0; }
prng.quick = function() { return arc4.g(4) / 0x100000000; }
prng.double = prng;
// Mix the randomness into accumulated entropy.
mixkey(tostring(arc4.S), pool);
// Calling convention: what to return as a function of prng, seed, is_math.
return (options.pass || callback ||
function(prng, seed, is_math_call, state) {
if (state) {
// Load the arc4 state from the given state if it has an S array.
if (state.S) { copy(state, arc4); }
// Only provide the .state method if requested via options.state.
prng.state = function() { return copy(arc4, {}); }
}
// If called as a method of Math (Math.seedrandom()), mutate
// Math.random because that is how seedrandom.js has worked since v1.0.
if (is_math_call) { math[rngname] = prng; return seed; }
// Otherwise, it is a newer calling convention, so return the
// prng directly.
else return prng;
})(
prng,
shortseed,
'global' in options ? options.global : (this == math),
options.state);
}...
```html
<script src="//cdnjs.cloudflare.com/ajax/libs/seedrandom/2.4.3/seedrandom.min.js">
</script>
```
```js
// Sets Math.random to a PRNG initialized using the given explicit seed.
Math.seedrandom('hello.');
console.log(Math.random()); // Always 0.9282578795792454
console.log(Math.random()); // Always 0.3752569768646784
// Sets Math.random to an ARC4-based PRNG that is autoseeded using the
// current time, dom state, and other accumulated local entropy.
// The generated seed string is returned.
Math.seedrandom();
...function impl(seed, opts) {
var xg = new Alea(seed),
state = opts && opts.state,
prng = xg.next;
prng.int32 = function() { return (xg.next() * 0x100000000) | 0; }
prng.double = function() {
return prng() + (prng() * 0x200000 | 0) * 1.1102230246251565e-16; // 2^-53
};
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
if (seed == null) seed = +(new Date);
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (state.X) copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}...
console.log(rng()); // Reasonably unpredictable.
// Mixing accumulated entropy.
rng = seedrandom('added entropy.', { entropy: true });
console.log(rng()); // As unpredictable as added entropy.
// Using alternate algorithms, as listed above.
var rng2 = seedrandom.xor4096('hello.')
console.log(rng2());
```
Require.js usage
----------------
...function impl(seed, opts) {
if (seed == null) seed = +(new Date);
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (state.x) copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function randomBytes(width) {
var out = new Uint8Array(width);
(global.crypto || global.msCrypto).getRandomValues(out);
return out;
}n/a
function seedrandom(seed, options, callback) {
var key = [];
options = (options == true) ? { entropy: true } : (options || {});
// Flatten the seed string or build one from local entropy if needed.
var shortseed = mixkey(flatten(
options.entropy ? [seed, tostring(pool)] :
(seed == null) ? autoseed() : seed, 3), key);
// Use the seed to initialize an ARC4 generator.
var arc4 = new ARC4(key);
// This function returns a random double in [0, 1) that contains
// randomness in every bit of the mantissa of the IEEE 754 value.
var prng = function() {
var n = arc4.g(chunks), // Start with a numerator n < 2 ^ 48
d = startdenom, // and denominator d = 2 ^ 48.
x = 0; // and no 'extra last byte'.
while (n < significance) { // Fill up all significant digits by
n = (n + x) * width; // shifting numerator and
d *= width; // denominator and generating a
x = arc4.g(1); // new least-significant-byte.
}
while (n >= overflow) { // To avoid rounding up, before adding
n /= 2; // last byte, shift everything
d /= 2; // right using integer math until
x >>>= 1; // we have exactly the desired bits.
}
return (n + x) / d; // Form the number within [0, 1).
};
prng.int32 = function() { return arc4.g(4) | 0; }
prng.quick = function() { return arc4.g(4) / 0x100000000; }
prng.double = prng;
// Mix the randomness into accumulated entropy.
mixkey(tostring(arc4.S), pool);
// Calling convention: what to return as a function of prng, seed, is_math.
return (options.pass || callback ||
function(prng, seed, is_math_call, state) {
if (state) {
// Load the arc4 state from the given state if it has an S array.
if (state.S) { copy(state, arc4); }
// Only provide the .state method if requested via options.state.
prng.state = function() { return copy(arc4, {}); }
}
// If called as a method of Math (Math.seedrandom()), mutate
// Math.random because that is how seedrandom.js has worked since v1.0.
if (is_math_call) { math[rngname] = prng; return seed; }
// Otherwise, it is a newer calling convention, so return the
// prng directly.
else return prng;
})(
prng,
shortseed,
'global' in options ? options.global : (this == math),
options.state);
}...
```html
<script src="//cdnjs.cloudflare.com/ajax/libs/seedrandom/2.4.3/seedrandom.min.js">
</script>
```
```js
// Sets Math.random to a PRNG initialized using the given explicit seed.
Math.seedrandom('hello.');
console.log(Math.random()); // Always 0.9282578795792454
console.log(Math.random()); // Always 0.3752569768646784
// Sets Math.random to an ARC4-based PRNG that is autoseeded using the
// current time, dom state, and other accumulated local entropy.
// The generated seed string is returned.
Math.seedrandom();
...function impl(seed, opts) {
var xg = new Alea(seed),
state = opts && opts.state,
prng = xg.next;
prng.int32 = function() { return (xg.next() * 0x100000000) | 0; }
prng.double = function() {
return prng() + (prng() * 0x200000 | 0) * 1.1102230246251565e-16; // 2^-53
};
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
if (seed == null) seed = +(new Date);
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (state.X) copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}...
console.log(rng()); // Reasonably unpredictable.
// Mixing accumulated entropy.
rng = seedrandom('added entropy.', { entropy: true });
console.log(rng()); // As unpredictable as added entropy.
// Using alternate algorithms, as listed above.
var rng2 = seedrandom.xor4096('hello.')
console.log(rng2());
```
Require.js usage
----------------
...function impl(seed, opts) {
if (seed == null) seed = +(new Date);
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (state.x) copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a
function impl(seed, opts) {
var xg = new XorGen(seed),
state = opts && opts.state,
prng = function() { return (xg.next() >>> 0) / 0x100000000; };
prng.double = function() {
do {
var top = xg.next() >>> 11,
bot = (xg.next() >>> 0) / 0x100000000,
result = (top + bot) / (1 << 21);
} while (result === 0);
return result;
};
prng.int32 = xg.next;
prng.quick = prng;
if (state) {
if (typeof(state) == 'object') copy(state, xg);
prng.state = function() { return copy(xg, {}); }
}
return prng;
}n/a