map_values.js (3152B)
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 * Maps values from one object to a new object having the same keys. 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 * - Iteration and insertion order are **not** guaranteed. 36 * - The function only operates on own properties, not inherited properties. 37 * 38 * 39 * @param {Object} obj - source object 40 * @param {Options} [options] - function options 41 * @param {*} [options.thisArg] - execution context 42 * @param {PositiveInteger} [options.limit] - maximum number of pending invocations at any one time 43 * @param {boolean} [options.series=false] - boolean indicating whether to wait for a previous invocation to complete before invoking a provided function for the next own property 44 * @param {Function} transform - transform function 45 * @param {Callback} done - function to invoke upon completion 46 * @throws {TypeError} first argument must be an object 47 * @throws {TypeError} options argument must be an object 48 * @throws {TypeError} must provide valid options 49 * @throws {TypeError} second-to-last argument must be a function 50 * @throws {TypeError} last argument must be a function 51 * @returns {void} 52 * 53 * @example 54 * var stat = require( 'fs' ).stat; 55 * 56 * function getStats( file, next ) { 57 * stat( file, onStats ); 58 * 59 * function onStats( error, data ) { 60 * if ( error ) { 61 * return next( error ); 62 * } 63 * next( null, data ); 64 * } 65 * } 66 * 67 * // Define a callback which handles errors: 68 * function done( error, out ) { 69 * if ( error ) { 70 * throw error; 71 * } 72 * console.log( out ); 73 * } 74 * 75 * // Create a dictionary of file names: 76 * var files = { 77 * 'file1': './beep.js', 78 * 'file2': './boop.js' 79 * }; 80 * 81 * var opts = { 82 * 'series': true 83 * }; 84 * 85 * // Process each file in `files`: 86 * mapValuesAsync( files, opts, getStats, done ); 87 */ 88 function mapValuesAsync( obj, options, transform, done ) { 89 if ( arguments.length < 4 ) { 90 return factory( options )( obj, transform ); 91 } 92 factory( options, transform )( obj, done ); 93 } 94 95 96 // EXPORTS // 97 98 module.exports = mapValuesAsync;