91 lines
3.0 KiB
JavaScript
91 lines
3.0 KiB
JavaScript
'use strict'
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var Transform = require('stream').Transform
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var util = require('util')
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var connect = require('stream-connect')
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var through = require('stream-via')
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/**
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* Returns a stream which fires a callback and becomes readable once all input is received.
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*
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* By default the callback is invoked with a Buffer instance containing all concatenated input. If you set the option `{ objectMode: true }` the callback is invoked with an array containing all objects received.
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*
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* @module collect-all
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*/
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module.exports = collectAll
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function CollectTransform (options) {
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options = options || {}
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if (!(this instanceof CollectTransform)) return new CollectTransform(options)
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Transform.call(this, options)
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this.options = options
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this.buf = options.objectMode || options.writableObjectMode ? [] : new Buffer(0)
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/* node 0.10 polyfil */
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if (!options.objectMode) {
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if (options.readableObjectMode) this._readableState.objectMode = true
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if (options.writableObjectMode) this._writableState.objectMode = true
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}
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}
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util.inherits(CollectTransform, Transform)
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CollectTransform.prototype._transform = function (chunk, enc, done) {
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if (chunk) {
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if (this.options.objectMode) {
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this.buf.push(chunk)
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} else {
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this.buf = Buffer.concat([ this.buf, chunk ])
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}
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}
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done()
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}
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CollectTransform.prototype._flush = function () {
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this.push(this.buf)
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this.push(null)
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}
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/**
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* @param [callback] {function} - Called once with the collected input data (by default a `Buffer` instance, or array in `objectMode`.). The value returned by this callback function will be passed downstream.
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* @param [options] {object} - [Stream options](https://nodejs.org/dist/latest-v5.x/docs/api/stream.html#stream_new_stream_readable_options) object, passed to the constructor for the stream returned by `collect-all`. If the callback function supplied returns a non-string/buffer value, set `options.objectMode` to `true`.
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* @return {external:Duplex}
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* @alias module:collect-all
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* @example
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* An example command-line client script - string input received at stdin is stamped with `received` then written to stdout.
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* ```js
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* var collectAll = require('collect-all')
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* process.stdin
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* .pipe(collectAll(function (input) {
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* input = 'received: ' + input
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* return input
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* }))
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* .pipe(process.stdout)
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* ```
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*
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* An object-mode example:
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* ```js
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* var collectAll = require('collect-all')
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*
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* function onAllCollected (collected) {
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* console.log('Objects collected: ' + collected.length)
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* }
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*
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* var stream = collectAll(onAllCollected, { objectMode: true })
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* stream.write({})
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* stream.write({})
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* stream.end({}) // outputs 'Objects collected: 3'
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* ```
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*/
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function collectAll (callback, options) {
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var collectTransform = new CollectTransform(options)
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if (callback && typeof callback === 'function') {
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return connect(collectTransform, through(callback, options))
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} else {
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return collectTransform
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}
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}
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/**
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* @external Duplex
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* @see https://nodejs.org/api/stream.html#stream_class_stream_duplex
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*/
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