getUnique

function getUnique(list) {
	'use strict';

	return Array.prototype.reduce.call(list, function(result, current) {
		if (result.indexOf(current) < 0) {
			result.push(current);
		}

		return result;
	}, []);
}

var a = {};
var b = {};
var u = getUnique([a,b,b,a]);
console.log(u[0] === a); // true
console.log(u[1] === b); // true
console.log(u.length === 2); // true