1. module multer
   1. function multer (options)
   2. function multer.counter ()
   3. function multer.diskStorage (opts)
   4. function multer.file_appender (strategy, req)
   5. function multer.memoryStorage (opts)
   6. object multer.counter.prototype
   7. object multer.file_appender.prototype
2. module multer.counter
   1. function multer.counter ()
3. module multer.counter.prototype
   1. function multer.counter.prototype.decrement ()
   2. function multer.counter.prototype.increment ()
   3. function multer.counter.prototype.isZero ()
   4. function multer.counter.prototype.onceZero (fn)
4. module multer.file_appender
   1. function multer.file_appender (strategy, req)
5. module multer.file_appender.prototype
   1. function multer.file_appender.prototype.insertPlaceholder (file)
   2. function multer.file_appender.prototype.removePlaceholder (placeholder)
   3. function multer.file_appender.prototype.replacePlaceholder (placeholder, file)

module multer

function multer (options)

• description and source-code

  function multer(options) {
    if (options === undefined) {
      return new Multer({})
    }
  
    if (typeof options === 'object' && options !== null) {
      return new Multer(options)
    }
  
    throw new TypeError('Expected object for argument options')
  }

• example usage

  n/a

function multer.counter ()

• description and source-code

  function Counter() {
    EventEmitter.call(this)
    this.value = 0
  }

• example usage

  n/a

function multer.diskStorage (opts)

• description and source-code

  diskStorage = function (opts) {
    return new DiskStorage(opts)
  }

• example usage

  ...
  ### `storage`
  
  #### `DiskStorage`
  
  The disk storage engine gives you full control on storing files to disk.
  
  ```javascript
  var storage = multer.diskStorage({
    destination: function (req, file, cb) {
      cb(null, '/tmp/my-uploads')
    },
    filename: function (req, file, cb) {
      cb(null, file.fieldname + '-' + Date.now())
    }
  })
  ...

function multer.file_appender (strategy, req)

• description and source-code

  function FileAppender(strategy, req) {
    this.strategy = strategy
    this.req = req
  
    switch (strategy) {
      case 'NONE': break
      case 'VALUE': break
      case 'ARRAY': req.files = []; break
      case 'OBJECT': req.files = Object.create(null); break
      default: throw new Error('Unknown file strategy: ' + strategy)
    }
  }

• example usage

  n/a

function multer.memoryStorage (opts)

• description and source-code

  memoryStorage = function (opts) {
    return new MemoryStorage(opts)
  }

• example usage

  ...
  
  #### `MemoryStorage`
  
  The memory storage engine stores the files in memory as `Buffer` objects. It
  doesn't have any options.
  
  ```javascript
  var storage = multer.memoryStorage()
  var upload = multer({ storage: storage })
  ```
  
  When using memory storage, the file info will contain a field called
  `buffer` that contains the entire file.
  
  **WARNING**: Uploading very large files, or relatively small files in large
  ...

module multer.counter

function multer.counter ()

• description and source-code

  function Counter() {
    EventEmitter.call(this)
    this.value = 0
  }

• example usage

  n/a

module multer.counter.prototype

function multer.counter.prototype.decrement ()

• description and source-code

  function decrement() {
    if (--this.value === 0) this.emit('zero')
  }

• example usage

  ...
  Object.defineProperty(file, 'stream', {
    configurable: true,
    enumerable: false,
    value: fileStream
  })
  
  fileStream.on('error', function (err) {
    pendingWrites.decrement()
    abortWithError(err)
  })
  
  fileStream.on('limit', function () {
    aborting = true
    abortWithCode('LIMIT_FILE_SIZE', fieldname)
  })
  ...

function multer.counter.prototype.increment ()

• description and source-code

  function increment() {
    this.value++
  }

• example usage

  ...
  
  if (!includeFile) {
    appender.removePlaceholder(placeholder)
    return fileStream.resume()
  }
  
  var aborting = false
  pendingWrites.increment()
  
  Object.defineProperty(file, 'stream', {
    configurable: true,
    enumerable: false,
    value: fileStream
  })
  ...

function multer.counter.prototype.isZero ()

• description and source-code

  function isZero() {
    return (this.value === 0)
  }

• example usage

  ...
  }
  
  Counter.prototype.isZero = function isZero () {
    return (this.value === 0)
  }
  
  Counter.prototype.onceZero = function onceZero (fn) {
    if (this.isZero()) return fn()
  
    this.once('zero', fn)
  }
  
  module.exports = Counter
  ...

function multer.counter.prototype.onceZero (fn)

• description and source-code

  function onceZero(fn) {
    if (this.isZero()) return fn()
  
    this.once('zero', fn)
  }

• example usage

  ...
        if (readFinished && pendingWrites.isZero() && !errorOccured) done()
      }
  
      function abortWithError (uploadError) {
        if (errorOccured) return
        errorOccured = true
  
        pendingWrites.onceZero(function () {
  function remove (file, cb) {
    storage._removeFile(req, file, cb)
  }
  
  removeUploadedFiles(uploadedFiles, remove, function (err, storageErrors) {
    if (err) return done(err)
  ...

module multer.file_appender

function multer.file_appender (strategy, req)

• description and source-code

  function FileAppender(strategy, req) {
    this.strategy = strategy
    this.req = req
  
    switch (strategy) {
      case 'NONE': break
      case 'VALUE': break
      case 'ARRAY': req.files = []; break
      case 'OBJECT': req.files = Object.create(null); break
      default: throw new Error('Unknown file strategy: ' + strategy)
    }
  }

• example usage

  n/a

module multer.file_appender.prototype

function multer.file_appender.prototype.insertPlaceholder (file)

• description and source-code

  insertPlaceholder = function (file) {
    var placeholder = {
      fieldname: file.fieldname
    }
  
    switch (this.strategy) {
      case 'NONE': break
      case 'VALUE': break
      case 'ARRAY': this.req.files.push(placeholder); break
      case 'OBJECT':
        if (this.req.files[file.fieldname]) {
          this.req.files[file.fieldname].push(placeholder)
        } else {
          this.req.files[file.fieldname] = [placeholder]
        }
        break
    }
  
    return placeholder
  }

• example usage

  ...
  var file = {
    fieldname: fieldname,
    originalname: filename,
    encoding: encoding,
    mimetype: mimetype
  }
  
  var placeholder = appender.insertPlaceholder(file)
  
  fileFilter(req, file, function (err, includeFile) {
    if (err) {
      appender.removePlaceholder(placeholder)
      return abortWithError(err)
    }
  ...

function multer.file_appender.prototype.removePlaceholder (placeholder)

• description and source-code

  removePlaceholder = function (placeholder) {
    switch (this.strategy) {
      case 'NONE': break
      case 'VALUE': break
      case 'ARRAY': arrayRemove(this.req.files, placeholder); break
      case 'OBJECT':
        if (this.req.files[placeholder.fieldname].length === 1) {
          delete this.req.files[placeholder.fieldname]
        } else {
          arrayRemove(this.req.files[placeholder.fieldname], placeholder)
        }
        break
    }
  }

• example usage

  ...
  mimetype: mimetype
        }
  
        var placeholder = appender.insertPlaceholder(file)
  
        fileFilter(req, file, function (err, includeFile) {
  if (err) {
    appender.removePlaceholder(placeholder)
    return abortWithError(err)
  }
  
  if (!includeFile) {
    appender.removePlaceholder(placeholder)
    return fileStream.resume()
  }
  ...

function multer.file_appender.prototype.replacePlaceholder (placeholder, file)

• description and source-code

  replacePlaceholder = function (placeholder, file) {
    if (this.strategy === 'VALUE') {
      this.req.file = file
      return
    }
  
    delete placeholder.fieldname
    objectAssign(placeholder, file)
  }

• example usage

  ...
          appender.removePlaceholder(placeholder)
          pendingWrites.decrement()
          return abortWithError(err)
        }
  
        var fileInfo = extend(file, info)
  
        appender.replacePlaceholder(placeholder, fileInfo)
        uploadedFiles.push(fileInfo)
        pendingWrites.decrement()
        indicateDone()
      })
    })
  })
  ...