lib/doDuring.js


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

'use strict';

import during from './during';

/**
 * The post-check version of {@link async.during}. To reflect the difference in
 * the order of operations, the arguments `test` and `fn` are switched.
 *
 * Also a version of {@link async.doWhilst} with asynchronous `test` function.
 * @name doDuring
 * @static
 * @memberOf async
 * @see async.during
 * @category Control Flow
 * @param {Function} fn - A function which is called each time `test` passes.
 * The function is passed a `callback(err)`, which must be called once it has
 * completed with an optional `err` argument. Invoked with (callback).
 * @param {Function} test - asynchronous truth test to perform before each
 * execution of `fn`. Invoked with (callback).
 * @param {Function} [callback] - A callback which is called after the test
 * function has failed and repeated execution of `fn` has stopped. `callback`
 * will be passed an error and any arguments passed to the final `fn`'s
 * callback. Invoked with (err, [results]);
 */
export default function doDuring(iteratee, test, cb) {
    var calls = 0;

    during(function(next) {
        if (calls++ < 1) return next(null, true);
        test.apply(this, arguments);
    }, iteratee, cb);
}