is-implemented.js 316 B

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  1. 'use strict';
  2. var global = require('es5-ext/global')
  3. , polyfill = require('../polyfill');
  4. module.exports = function (t, a) {
  5. var cache;
  6. a(typeof t(), 'boolean');
  7. cache = global.Symbol;
  8. global.Symbol = polyfill;
  9. a(t(), true);
  10. if (cache === undefined) delete global.Symbol;
  11. else global.Symbol = cache;
  12. };