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JavaScript

'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
var _createTester = require('./internal/createTester.js');
var _createTester2 = _interopRequireDefault(_createTester);
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 the first value in `coll` that passes an async truth test. The
* `iteratee` is applied in parallel, meaning the first iteratee to return
* `true` will fire the detect `callback` with that result. That means the
* result might not be the first item in the original `coll` (in terms of order)
* that passes the test.
* If order within the original `coll` is important, then look at
* [`detectSeries`]{@link module:Collections.detectSeries}.
*
* @name detect
* @static
* @memberOf module:Collections
* @method
* @alias find
* @category Collections
* @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
* The iteratee must complete with a boolean value as its result.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called as soon as any
* iteratee returns `true`, or after all the `iteratee` functions have finished.
* Result will be the first item in the array that passes the truth test
* (iteratee) or the value `undefined` if none passed. Invoked with
* (err, result).
* @returns {Promise} a promise, if a callback is omitted
* @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
*
* // asynchronous function that checks if a file exists
* function fileExists(file, callback) {
* fs.access(file, fs.constants.F_OK, (err) => {
* callback(null, !err);
* });
* }
*
* async.detect(['file3.txt','file2.txt','dir1/file1.txt'], fileExists,
* function(err, result) {
* console.log(result);
* // dir1/file1.txt
* // result now equals the first file in the list that exists
* }
*);
*
* // Using Promises
* async.detect(['file3.txt','file2.txt','dir1/file1.txt'], fileExists)
* .then(result => {
* console.log(result);
* // dir1/file1.txt
* // result now equals the first file in the list that exists
* }).catch(err => {
* console.log(err);
* });
*
* // Using async/await
* async () => {
* try {
* let result = await async.detect(['file3.txt','file2.txt','dir1/file1.txt'], fileExists);
* console.log(result);
* // dir1/file1.txt
* // result now equals the file in the list that exists
* }
* catch (err) {
* console.log(err);
* }
* }
*
*/
function detect(coll, iteratee, callback) {
return (0, _createTester2.default)(bool => bool, (res, item) => item)(_eachOf2.default, coll, iteratee, callback);
}
exports.default = (0, _awaitify2.default)(detect, 3);
module.exports = exports['default'];