summaryrefslogtreecommitdiff
path: root/lib/mapValuesLimit.js
blob: 762b871e78be38c87a1edc1811776d55d27f5af7 (plain)
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
33
import eachOfLimit from './eachOfLimit';

/**
 * The same as `mapValues` but runs a maximum of `limit` async operations at a
 * time.
 *
 * @name mapValuesLimit
 * @static
 * @memberOf async
 * @see async.mapValues
 * @category Collection
 * @param {Object} obj - A collection to iterate over.
 * @param {number} limit - The maximum number of async operations at a time.
 * @param {Function} iteratee - A function to apply to each value in `obj`.
 * The iteratee is passed a `callback(err, transformed)` which must be called
 * once it has completed with an error (which can be `null`) and a
 * transformed value. Invoked with (value, key, callback).
 * @param {Function} [callback] - A callback which is called when all `iteratee`
 * functions have finished, or an error occurs. Result is an object of the
 * transformed values from the `obj`. Invoked with (err, result).
 */
export default function mapValuesLimit(obj, limit, iteratee, callback) {
    var newObj = {};
    eachOfLimit(obj, limit, function(val, key, next) {
        iteratee(val, key, function (err, result) {
            if (err) return next(err);
            newObj[key] = result;
            next();
        });
    }, function (err) {
        callback(err, newObj);
    });
}