Add requestAnimationFrame polyfill util

Author: myarcane

src/util.js

@@ -13,3 +13,32 @@ export function onlyChild(children) {
 export function filterNullChildren(children) {
 	return children && children.filter(i => i !== null);
 }
+
+export const requestAnimationFrame = (() => {
+	let raf;
+
+	if (typeof window !== 'undefined') {
+		raf = window.requestAnimationFrame;
+		const prefixes = ['ms', 'moz', 'webkit', 'o'];
+		for (let i = 0; i < prefixes.length; i++) {
+			if (raf) break;
+			raf = window[`${prefixes[i]}RequestAnimationFrame}`];
+		}
+	}
+
+	if (!raf) {
+		let timeLast = 0;
+		raf = (callback) => {
+			const timeCurrent = new Date().getTime();
+
+			/* Dynamically set the delay on a per-tick basis to more closely match 60fps. */
+			/* Technique by Erik Moller. MIT license: https://gist.github.com/paulirish/1579671. */
+			const timeDelta = Math.max(0, 16 - (timeCurrent - timeLast));
+			timeLast = timeCurrent + timeDelta;
+
+			return setTimeout(() => { callback(timeCurrent + timeDelta); }, timeDelta);
+		};
+	}
+
+	return raf;
+})();