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JavaScript

'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
var _filter2 = require('./internal/filter.js');
var _filter3 = _interopRequireDefault(_filter2);
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 }; }
/**
* Returns a new array of all the values in `coll` which pass an async truth
* test. This operation is performed in parallel, but the results array will be
* in the same order as the original.
*
* @name filter
* @static
* @memberOf module:Collections
* @method
* @alias select
* @category Collection
* @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
* @param {Function} iteratee - A truth test to apply to each item in `coll`.
* The `iteratee` is passed a `callback(err, truthValue)`, which must be called
* with a boolean argument once it has completed. Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Invoked with (err, results).
* @returns {Promise} a promise, if no callback provided
* @example
*
* // dir1 is a directory that contains file1.txt, file2.txt
* // dir2 is a directory that contains file3.txt, file4.txt
* // dir3 is a directory that contains file5.txt
*
* const files = ['dir1/file1.txt','dir2/file3.txt','dir3/file6.txt'];
*
* // asynchronous function that checks if a file exists
* function fileExists(file, callback) {
* fs.access(file, fs.constants.F_OK, (err) => {
* callback(null, !err);
* });
* }
*
* // Using callbacks
* async.filter(files, fileExists, function(err, results) {
* if(err) {
* console.log(err);
* } else {
* console.log(results);
* // [ 'dir1/file1.txt', 'dir2/file3.txt' ]
* // results is now an array of the existing files
* }
* });
*
* // Using Promises
* async.filter(files, fileExists)
* .then(results => {
* console.log(results);
* // [ 'dir1/file1.txt', 'dir2/file3.txt' ]
* // results is now an array of the existing files
* }).catch(err => {
* console.log(err);
* });
*
* // Using async/await
* async () => {
* try {
* let results = await async.filter(files, fileExists);
* console.log(results);
* // [ 'dir1/file1.txt', 'dir2/file3.txt' ]
* // results is now an array of the existing files
* }
* catch (err) {
* console.log(err);
* }
* }
*
*/
function filter(coll, iteratee, callback) {
return (0, _filter3.default)(_eachOf2.default, coll, iteratee, callback);
}
exports.default = (0, _awaitify2.default)(filter, 3);
module.exports = exports['default'];