Shuffles array in place. ES6 version

array-shuffle.js

/**
 * Shuffles array in place. ES6 version
 * @param {Array} a items An array containing the items.
 * https://stackoverflow.com/questions/6274339/how-can-i-shuffle-an-array
 */
shuffle(a: Array<any>) {
	for (let i = a.length - 1; i > 0; i--) {
		const j = Math.floor(Math.random() * (i + 1));
		[a[i], a[j]] = [a[j], a[i]];
	}
	return a;
}