is-implemented.js 188 Bytes RawBlameHistoryPermalink 1 2 3 4 5 6 7 "use strict"; module.exports = function () { var arr = [1, 2, 3, 4, 5]; if (typeof arr.copyWithin !== "function") return false; return String(arr.copyWithin(1, 3)) === "1,4,5,4,5"; };