Function doDuring

lib/doDuring.js:26–45

(fn, test, callback)

 * will be passed an error if one occurred, otherwise `null`.
 */
export default function doDuring(fn, test, callback) {
    callback = onlyOnce(callback || noop);
    var _fn = wrapAsync(fn);
    var _test = wrapAsync(test);

    var next = rest(function(err, args) {
        if (err)  return callback(err);
        args.push(check);
        _test.apply(this, args);
    });

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

    check(null, true);

}