devsite/node_modules/async/map.js

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2024-07-08 01:49:38 +00:00
'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;