Function during

lib/during.js:41–58

(test, fn, callback)

 * );
 */
export default function during(test, fn, callback) {
    callback = onlyOnce(callback || noop);
    var _fn = wrapAsync(fn);
    var _test = wrapAsync(test);

    function next(err) {
        if (err) return callback(err);
        _test(check);
    }

    function check(err, truth) {
        if (err) return callback(err);
        if (!truth) return callback(null);
        _fn(next);
    }

    _test(check);
}