IO event-loop pattern.ts

type IOEvent =
  | { type: "keyDown" | "keyUp"; keyCode: number }
  | { type: "mouseDown" | "mouseUp"; mouseButton: number }
  | { type: "mouseMove" | "mouseWheel"; x: number; y: number };

class IOEventListener {
  private eventQueue = [] as IOEvent[];
  private isRunning = false;
  private eventQueueGenerator: Generator<undefined, void, unknown> | null = null;

  dispatchIOEvent = (event: IOEvent) => {
    if (!this.isRunning) return;
    this.eventQueue.push(event);
    this.eventQueueGenerator?.next();
  };

  *eventLoop() {
    while (this.isRunning) {
      const event = this.eventQueue[0] || { type: "null" };
      this.eventQueue.shift();

      switch (event.type) {
        case "keyDown":
          console.log("keyDown", event.keyCode);
          break;

        case "keyUp":
          console.log("keyUp", event.keyCode);
          break;

        case "mouseDown":
          console.log("mouseDown", event.mouseButton);
          break;

        case "mouseUp":
          console.log("mouseUp", event.mouseButton);
          break;

        case "mouseMove":
          console.log("mouseMove", event.x, event.y);
          break;

        case "mouseWheel":
          console.log("mouseWheel", event.x, event.y);
          break;

        // 큐가 비어 있는 경우
        default:
          console.log("event not found", event);
      }

      yield;
    }
  }

  run = () => {
    if (this.isRunning) return;
    this.isRunning = true;
    this.eventQueueGenerator = this.eventLoop();
  };

  stop = () => {
    this.isRunning = false;
    this.eventQueueGenerator = null;
    this.eventQueue = [];
  };
}

function main() {
  const eventListener = new IOEventListener();

  eventListener.run();

  eventListener.dispatchIOEvent({ type: "keyDown", keyCode: 65 });
  eventListener.dispatchIOEvent({ type: "keyUp", keyCode: 65 });

  eventListener.dispatchIOEvent({ type: "keyDown", keyCode: 66 });
  eventListener.dispatchIOEvent({ type: "keyUp", keyCode: 66 });

  eventListener.stop();
}

main();