monkeydo/worker/Monkey.js

// Task scheduler and iterator of Monkeydo manifests

class Monkey {
	constructor(manifest) {
		this.data = manifest.body;
		this.dataLength = this.data.length - 1;

		this.flags = {
			playing: 0,
			stacking: 0, // Subsequent calls to play() will build a queue (jQuery-style)
			loop: 0, // Loop n times; <0 = infinite
		}

		this.i = 0;
		this.queue = {
			task: null,
			next: null
		}
		Object.seal(this.queue);
	}

	// Parse task components and send them to main thread
	run(data) {
		this.i++; // Advance index
		postMessage(data);
		console.log(this.i);
	}

	// Interrupt timeout and put monkey to sleep
	interrupt() {
		clearTimeout(this.queue.task);
		clearTimeout(this.queue.next);
		this.queue.task = null;
		this.queue.next = null;
		this.flags.playing = 0;
	}

	play() {
		if(this.flags.playing) {
			if(this.flags.stacking) {
				this.flags.loop++;
			}
			return;
		}
		this.queueNext();
	}

	// Schedule task for execution by index
	queueNext() {
		this.flags.playing = 1;
		const data = this.data[this.i];

		// Schedule the current task to run after the specified wait time
		this.queue.task = setTimeout(() => this.run(data.do),data.wait);

		// We're out of tasks to schedule..
		if(this.i >= this.dataLength) {
			this.i = -1;
			// Exit if we're out of loops
			if(this.flags.loop === 0) {
				this.flags.playing = 0;
				return false;
			}
			
			if(this.flags.loop <= -1) {
				this.flags.loop = this.flags.loop - 1;
			}
		}

		// Run this function again when the scheduled task will fire
		this.queue.next = setTimeout(() => this.queueNext(),data.wait);
	}
}

// Global message event handler for this worker
onmessage = (message) => {
	const type = message.data[0] ? message.data[0] : message.data;
	const data = message.data[1];

	switch(type) {
		// Attempt to load manfiest provided by initiator thread
		case "GIVE_MANIFEST":
			try {
				this.monkey = new Monkey(data);
				postMessage("OK");
			}
			catch(error) {
				postMessage(["MANIFEST_ERROR",error]);
			}
			break;

		// Set playstate
		case "SET_PLAYING":
			if(data === true) {
				this.monkey.play();
				return;
			}
			// Treat data that isn't a TRUE boolean as an interrupt
			this.monkey.interrupt();
			break;

		case "GET_FLAG":
			const flag = this.monkey.flags[data];
			postMessage(parseInt(flag));
			break;

		case "SET_FLAG":
			console.log(data);
			this.monkey.flags[data[0]] = data[1];
			break;

		default: return; // No op
	}
}