Function reduce

lib/reduce.js:46–57

(coll, memo, iteratee, callback)

 * });
 */
export default function reduce(coll, memo, iteratee, callback) {
    callback = once(callback || noop);
    var _iteratee = wrapAsync(iteratee);
    eachOfSeries(coll, function(x, i, callback) {
        _iteratee(memo, x, function(err, v) {
            memo = v;
            callback(err);
        });
    }, function(err) {
        callback(err, memo);
    });
}