is-implemented.js 220 Bytes Raw Blame History Permalink 1 2 3 4 5 6 7 8 9 10 11 "use strict"; var fn = function (value) { return value > 3; }; module.exports = function () { var arr = [1, 2, 3, 4, 5, 6]; if (typeof arr.findIndex !== "function") return false; return arr.findIndex(fn) === 3; };