Coroutine in Js

    var lastFrameTime = Date.now();
    function updateFrame() {
        var thisFrameTime = Date.now();
        var deltaTime = thisFrameTime - lastFrameTime;
        lastFrameTime = thisFrameTime;
        coroutine.update(deltaTime);
        requestAnimationFrame(updateFrame);
    }
    updateFrame();

    coroutine.add(function*(dt) {
        updateLuminance();
        dt = yield undefined;
        dt = yield* waitCount();
        dt = yield* waitFunc(fadeOut);
        dt = yield* waitFunc(fadeIn);
        dt = yield* coroutine.waitForSeconds(0.5);
       
        message('안녕하세요. 게임을 시작 할려면');
        message('"Enter"키를 눌러 주세요!!!');
        dt = yield* waitInput();
        dt = yield* waitFunc(fadeOut);
        dt = yield* waitFunc(fadeIn);
        message('당신은 마법사로 조선의 단군을 구해야 합니다.'); 
        dt = yield* waitInput();
    });

coroutine.update = function(dt) {
    var i = 0;
    while(i < coroutine.job.length)
    {
        var c = coroutine.job[i];
        // this passes delta-time to the coroutine using magic
        var done = c.next(dt).done;

        // remove any couroutines that have finished
        if(done)
            coroutine.job.splice(i, 1);
        else
            i++;
    }
}

coroutine.waitForSeconds = function*(durationSec) {
    var durationMs = durationSec * 1000;
    var startMs = Date.now();
    var dt = 0;
    while (Date.now() - startMs < durationMs) {
        dt = yield undefined;
    }
    return dt;
}