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import noop from 'lodash/noop';
import eachSeries from './eachSeries';
import rest from './internal/rest';
/**
* 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|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).
* @example
* async.try([
* 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.
* });
*
*/
export default function tryEach(tasks, callback) {
var error = null;
var result;
callback = callback || noop;
eachSeries(tasks, function(task, callback) {
task(rest(function (err, args) {
if (args.length <= 1) {
args = args[0];
}
error = err;
result = args;
callback(!err);
}));
}, function () {
callback(error, result);
});
}
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