yitonghe00/Eloquent JavaScript 1602 Pausing the game.html

## Eloquent JavaScript 1602 Pausing the game.html
<link rel="stylesheet" href="css/game.css">

<body>
<script>
  // The old runLevel function. Modify this...
  function runLevel(level, Display) {
    let display = new Display(document.body, level);
    let state = State.start(level);
    let ending = 1;

    return new Promise(resolve => {
      let paused = false;
      const escHandler = (event) => {
        if (event.key === 'Escape') {
          event.preventDefault();
          if (paused) runAnimation(frame);
          paused = !paused;
        }
      }
      window.addEventListener('keydown', escHandler);
      const arrowKeys = trackKeys(["ArrowLeft", "ArrowRight", "ArrowUp"]);

      const frame = function(time) {
        state = state.update(time, arrowKeys);
        display.syncState(state);
        if (state.status == "playing") {
          return true && !paused;
        } else if (ending > 0) {
          ending -= time;
          return true && !paused;
        } else {
          display.clear();
          window.removeEventListener('keydown', escHandler);
          arrowKeys.unregister();
          resolve(state.status);
          return false;
        }
      }

      runAnimation(frame);
    });
  }

 function trackKeys(keys) {
  let down = Object.create(null);
  function track(event) {
    if (keys.includes(event.key)) {
      down[event.key] = event.type == "keydown";
      event.preventDefault();
    }
  }
  window.addEventListener("keydown", track);
  window.addEventListener("keyup", track);
  down.unregister = () => {
    window.removeEventListener("keydown", track);
    window.removeEventListener("keyup", track);
  }
  return down;
 }

  runGame(GAME_LEVELS, DOMDisplay);
</script>
</body>
	<link rel="stylesheet" href="css/game.css">

	<body>
	<script>
	// The old runLevel function. Modify this...
	function runLevel(level, Display) {
	let display = new Display(document.body, level);
	let state = State.start(level);
	let ending = 1;

	return new Promise(resolve => {
	let paused = false;
	const escHandler = (event) => {
	if (event.key === 'Escape') {
	event.preventDefault();
	if (paused) runAnimation(frame);
	paused = !paused;
	}
	}
	window.addEventListener('keydown', escHandler);
	const arrowKeys = trackKeys(["ArrowLeft", "ArrowRight", "ArrowUp"]);

	const frame = function(time) {
	state = state.update(time, arrowKeys);
	display.syncState(state);
	if (state.status == "playing") {
	return true && !paused;
	} else if (ending > 0) {
	ending -= time;
	return true && !paused;
	} else {
	display.clear();
	window.removeEventListener('keydown', escHandler);
	arrowKeys.unregister();
	resolve(state.status);
	return false;
	}
	}

	runAnimation(frame);
	});
	}

	function trackKeys(keys) {
	let down = Object.create(null);
	function track(event) {
	if (keys.includes(event.key)) {
	down[event.key] = event.type == "keydown";
	event.preventDefault();
	}
	}
	window.addEventListener("keydown", track);
	window.addEventListener("keyup", track);
	down.unregister = () => {
	window.removeEventListener("keydown", track);
	window.removeEventListener("keyup", track);
	}
	return down;
	}

	runGame(GAME_LEVELS, DOMDisplay);
	</script>
	</body>