is-implemented.js 188 B

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  1. 'use strict';
  2. module.exports = function () {
  3. var arr = [1, 2, 3, 4, 5];
  4. if (typeof arr.copyWithin !== 'function') return false;
  5. return String(arr.copyWithin(1, 3)) === '1,4,5,4,5';
  6. };