142 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			142 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| 'use strict';
 | |
| 
 | |
| Object.defineProperty(exports, "__esModule", {
 | |
|     value: true
 | |
| });
 | |
| 
 | |
| var _map2 = require('./internal/map.js');
 | |
| 
 | |
| var _map3 = _interopRequireDefault(_map2);
 | |
| 
 | |
| var _eachOf = require('./eachOf.js');
 | |
| 
 | |
| var _eachOf2 = _interopRequireDefault(_eachOf);
 | |
| 
 | |
| var _awaitify = require('./internal/awaitify.js');
 | |
| 
 | |
| var _awaitify2 = _interopRequireDefault(_awaitify);
 | |
| 
 | |
| function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 | |
| 
 | |
| /**
 | |
|  * Produces a new collection of values by mapping each value in `coll` through
 | |
|  * the `iteratee` function. The `iteratee` is called with an item from `coll`
 | |
|  * and a callback for when it has finished processing. Each of these callbacks
 | |
|  * takes 2 arguments: an `error`, and the transformed item from `coll`. If
 | |
|  * `iteratee` passes an error to its callback, the main `callback` (for the
 | |
|  * `map` function) is immediately called with the error.
 | |
|  *
 | |
|  * Note, that since this function applies the `iteratee` to each item in
 | |
|  * parallel, there is no guarantee that the `iteratee` functions will complete
 | |
|  * in order. However, the results array will be in the same order as the
 | |
|  * original `coll`.
 | |
|  *
 | |
|  * If `map` is passed an Object, the results will be an Array.  The results
 | |
|  * will roughly be in the order of the original Objects' keys (but this can
 | |
|  * vary across JavaScript engines).
 | |
|  *
 | |
|  * @name map
 | |
|  * @static
 | |
|  * @memberOf module:Collections
 | |
|  * @method
 | |
|  * @category Collection
 | |
|  * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
 | |
|  * @param {AsyncFunction} iteratee - An async function to apply to each item in
 | |
|  * `coll`.
 | |
|  * The iteratee should complete with the transformed item.
 | |
|  * Invoked with (item, callback).
 | |
|  * @param {Function} [callback] - A callback which is called when all `iteratee`
 | |
|  * functions have finished, or an error occurs. Results is an Array of the
 | |
|  * transformed items from the `coll`. Invoked with (err, results).
 | |
|  * @returns {Promise} a promise, if no callback is passed
 | |
|  * @example
 | |
|  *
 | |
|  * // file1.txt is a file that is 1000 bytes in size
 | |
|  * // file2.txt is a file that is 2000 bytes in size
 | |
|  * // file3.txt is a file that is 3000 bytes in size
 | |
|  * // file4.txt does not exist
 | |
|  *
 | |
|  * const fileList = ['file1.txt','file2.txt','file3.txt'];
 | |
|  * const withMissingFileList = ['file1.txt','file2.txt','file4.txt'];
 | |
|  *
 | |
|  * // asynchronous function that returns the file size in bytes
 | |
|  * function getFileSizeInBytes(file, callback) {
 | |
|  *     fs.stat(file, function(err, stat) {
 | |
|  *         if (err) {
 | |
|  *             return callback(err);
 | |
|  *         }
 | |
|  *         callback(null, stat.size);
 | |
|  *     });
 | |
|  * }
 | |
|  *
 | |
|  * // Using callbacks
 | |
|  * async.map(fileList, getFileSizeInBytes, function(err, results) {
 | |
|  *     if (err) {
 | |
|  *         console.log(err);
 | |
|  *     } else {
 | |
|  *         console.log(results);
 | |
|  *         // results is now an array of the file size in bytes for each file, e.g.
 | |
|  *         // [ 1000, 2000, 3000]
 | |
|  *     }
 | |
|  * });
 | |
|  *
 | |
|  * // Error Handling
 | |
|  * async.map(withMissingFileList, getFileSizeInBytes, function(err, results) {
 | |
|  *     if (err) {
 | |
|  *         console.log(err);
 | |
|  *         // [ Error: ENOENT: no such file or directory ]
 | |
|  *     } else {
 | |
|  *         console.log(results);
 | |
|  *     }
 | |
|  * });
 | |
|  *
 | |
|  * // Using Promises
 | |
|  * async.map(fileList, getFileSizeInBytes)
 | |
|  * .then( results => {
 | |
|  *     console.log(results);
 | |
|  *     // results is now an array of the file size in bytes for each file, e.g.
 | |
|  *     // [ 1000, 2000, 3000]
 | |
|  * }).catch( err => {
 | |
|  *     console.log(err);
 | |
|  * });
 | |
|  *
 | |
|  * // Error Handling
 | |
|  * async.map(withMissingFileList, getFileSizeInBytes)
 | |
|  * .then( results => {
 | |
|  *     console.log(results);
 | |
|  * }).catch( err => {
 | |
|  *     console.log(err);
 | |
|  *     // [ Error: ENOENT: no such file or directory ]
 | |
|  * });
 | |
|  *
 | |
|  * // Using async/await
 | |
|  * async () => {
 | |
|  *     try {
 | |
|  *         let results = await async.map(fileList, getFileSizeInBytes);
 | |
|  *         console.log(results);
 | |
|  *         // results is now an array of the file size in bytes for each file, e.g.
 | |
|  *         // [ 1000, 2000, 3000]
 | |
|  *     }
 | |
|  *     catch (err) {
 | |
|  *         console.log(err);
 | |
|  *     }
 | |
|  * }
 | |
|  *
 | |
|  * // Error Handling
 | |
|  * async () => {
 | |
|  *     try {
 | |
|  *         let results = await async.map(withMissingFileList, getFileSizeInBytes);
 | |
|  *         console.log(results);
 | |
|  *     }
 | |
|  *     catch (err) {
 | |
|  *         console.log(err);
 | |
|  *         // [ Error: ENOENT: no such file or directory ]
 | |
|  *     }
 | |
|  * }
 | |
|  *
 | |
|  */
 | |
| function map(coll, iteratee, callback) {
 | |
|     return (0, _map3.default)(_eachOf2.default, coll, iteratee, callback);
 | |
| }
 | |
| exports.default = (0, _awaitify2.default)(map, 3);
 | |
| module.exports = exports.default; |