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