stdin.js

    /**
     * Makes the passed function yieldable. Each time the function calls
     * yield, execution is suspended for the yielded number of
     * milliseconds.
     *
     * Example:
     *      let func = yieldable(function () {
     *          util.dump(Date.now()); // 0
     *          yield 1500;
     *          util.dump(Date.now()); // 1500
     *      });
     *      func();
     *
     * @param {function} func The function to mangle.
     * @returns {function} A new function which may not execute
     *      synchronously.
     */
    yieldable: function yieldable(func)
        function magic() {
            let gen = func.apply(this, arguments);
            (function next() {
                try {
                    util.timeout(next, gen.next());
                }
                catch (e if e instanceof StopIteration) {};
            })();
        },