time-to-botec

Benchmark sampling in different programming languages
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reduce.js (3130B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2018 The Stdlib Authors.
      5 *
      6 * Licensed under the Apache License, Version 2.0 (the "License");
      7 * you may not use this file except in compliance with the License.
      8 * You may obtain a copy of the License at
      9 *
     10 *    http://www.apache.org/licenses/LICENSE-2.0
     11 *
     12 * Unless required by applicable law or agreed to in writing, software
     13 * distributed under the License is distributed on an "AS IS" BASIS,
     14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15 * See the License for the specific language governing permissions and
     16 * limitations under the License.
     17 */
     18 
     19 'use strict';
     20 
     21 // MODULES //
     22 
     23 var factory = require( './factory.js' );
     24 
     25 
     26 // MAIN //
     27 
     28 /**
     29 * Applies a function against an accumulator and each element in a collection and return the accumulated result.
     30 *
     31 * ## Notes
     32 *
     33 * -   If a provided function calls the provided callback with a truthy error argument, the function suspends execution and immediately calls the `done` callback for subsequent error handling.
     34 * -   This function does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
     35 *
     36 *
     37 * @param {Collection} collection - input collection
     38 * @param {*} initial - initial value
     39 * @param {Options} [options] - function options
     40 * @param {*} [options.thisArg] - execution context
     41 * @param {PositiveInteger} [options.limit] - maximum number of pending invocations at any one time
     42 * @param {boolean} [options.series=true] - boolean indicating whether to wait for a previous invocation to complete before invoking a provided function for the next element in a collection
     43 * @param {Function} fcn - function to invoke for each element in a collection
     44 * @param {Callback} done - function to invoke upon completion
     45 * @throws {TypeError} first argument must be a collection
     46 * @throws {TypeError} options argument must be an object
     47 * @throws {TypeError} must provide valid options
     48 * @throws {TypeError} second-to-last argument must be a function
     49 * @throws {TypeError} last argument must be a function
     50 * @returns {void}
     51 *
     52 * @example
     53 * var readFile = require( '@stdlib/fs/read-file' );
     54 *
     55 * function done( error, acc ) {
     56 *     if ( error ) {
     57 *         throw error;
     58 *     }
     59 *     console.log( acc.count );
     60 * }
     61 *
     62 * function read( acc, file, next ) {
     63 *     var opts = {
     64 *         'encoding': 'utf8'
     65 *     };
     66 *     readFile( file, opts, onFile );
     67 *
     68 *     function onFile( error ) {
     69 *         if ( error ) {
     70 *             return next( null, acc );
     71 *         }
     72 *         acc.count += 1;
     73 *         next( null, acc );
     74 *     }
     75 * }
     76 *
     77 * var files = [
     78 *     './beep.js',
     79 *     './boop.js'
     80 * ];
     81 * var acc = {
     82 *     'count': 0
     83 * };
     84 * reduceAsync( files, acc, read, done );
     85 */
     86 function reduceAsync( collection, initial, options, fcn, done ) {
     87 	if ( arguments.length < 5 ) {
     88 		return factory( options )( collection, initial, fcn );
     89 	}
     90 	factory( options, fcn )( collection, initial, done );
     91 }
     92 
     93 
     94 // EXPORTS //
     95 
     96 module.exports = reduceAsync;