Array.diff

Array.diff.js

Array.implement({
	diff: function() {
		var r = [], idx = -1, diff, len, i, pos, array, keys;
		keys = ((keys = arguments[arguments.length-1]) === true);
		while(n < arguments.length) {
			array = arguments[n++];
			for(len = array.length, pos = this.length; len--;){
				for(i = pos; i && (diff = array[len] !== this[--i]););
				diff && (r[++idx] = keys ? len : array[len]);
			}
			return r;
		}
		return [];
	}
});