every

Iterates over an array or object, passing each thing to the fn you provide. if the function returns true every time, every returns true. otherwise every returns false

(function () {

// 1, 2, and 3 are all less than 4.
[1,2,3][o.every](function (n) {return n < 4;}); // true;

// 1, and 2 are less than 4 but 5 isnt...
[1,2,5][o.every](function (n) {return n < 4;}); // false;

})();