Wrap requestAnimationFrame to implement return value & cancelAnimationFrame

fix-raf.js

const callbacks = new Map();
let id = 0;

const realRequestAnimationFrame = window.requestAnimationFrame;

window.requestAnimationFrame = function(cb) {
	id++;
	callbacks.set(id, cb);
	return id;
}

window.cancelAnimationFrame = function(id) {
	callbacks.delete(id);
}

function tick(timestamp) {
	realRequestAnimationFrame(tick);
	let cbs = Array.from(callbacks.values());
	callbacks.clear();
	for (let cb of cbs) {
		cb(timestamp);
	}
}

realRequestAnimationFrame(tick);