Object assign

assign.js

if (!Object.prototype.assign) {  
    Object.prototype.assign = function() {
        var args = [].slice.call(arguments),
            target = args.shift();

        return args.reduce(function(base, obj) {
            Object.keys(obj).forEach(function(prop) {
                if (obj.hasOwnProperty(prop)) {
                    base[prop] = obj[prop];
                }
            });
            return base;
        }, target);
    }
}