tryEach.js
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'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
var _eachSeries = require('./eachSeries');
var _eachSeries2 = _interopRequireDefault(_eachSeries);
var _wrapAsync = require('./internal/wrapAsync');
var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
var _awaitify = require('./internal/awaitify');
var _awaitify2 = _interopRequireDefault(_awaitify);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
/**
* It runs each task in series but stops whenever any of the functions were
* successful. If one of the tasks were successful, the `callback` will be
* passed the result of the successful task. If all tasks fail, the callback
* will be passed the error and result (if any) of the final attempt.
*
* @name tryEach
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array|Iterable|AsyncIterable|Object} tasks - A collection containing functions to
* run, each function is passed a `callback(err, result)` it must call on
* completion with an error `err` (which can be `null`) and an optional `result`
* value.
* @param {Function} [callback] - An optional callback which is called when one
* of the tasks has succeeded, or all have failed. It receives the `err` and
* `result` arguments of the last attempt at completing the `task`. Invoked with
* (err, results).
* @returns {Promise} a promise, if no callback is passed
* @example
* async.tryEach([
* function getDataFromFirstWebsite(callback) {
* // Try getting the data from the first website
* callback(err, data);
* },
* function getDataFromSecondWebsite(callback) {
* // First website failed,
* // Try getting the data from the backup website
* callback(err, data);
* }
* ],
* // optional callback
* function(err, results) {
* Now do something with the data.
* });
*
*/
function tryEach(tasks, callback) {
var error = null;
var result;
return (0, _eachSeries2.default)(tasks, (task, taskCb) => {
(0, _wrapAsync2.default)(task)((err, ...args) => {
if (err === false) return taskCb(err);
if (args.length < 2) {
[result] = args;
} else {
result = args;
}
error = err;
taskCb(err ? null : {});
});
}, () => callback(error, result));
}
exports.default = (0, _awaitify2.default)(tryEach);
module.exports = exports['default'];