esnext.weak-map.get-or-insert-computed.js 842 B

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  1. 'use strict';
  2. var $ = require('../internals/export');
  3. var aCallable = require('../internals/a-callable');
  4. var aWeakMap = require('../internals/a-weak-map');
  5. var aWeakKey = require('../internals/a-weak-key');
  6. var WeakMapHelpers = require('../internals/weak-map-helpers');
  7. var IS_PURE = require('../internals/is-pure');
  8. var get = WeakMapHelpers.get;
  9. var has = WeakMapHelpers.has;
  10. var set = WeakMapHelpers.set;
  11. // `WeakMap.prototype.getOrInsertComputed` method
  12. // https://github.com/tc39/proposal-upsert
  13. $({ target: 'WeakMap', proto: true, real: true, forced: IS_PURE }, {
  14. getOrInsertComputed: function getOrInsertComputed(key, callbackfn) {
  15. aWeakMap(this);
  16. aWeakKey(key);
  17. aCallable(callbackfn);
  18. if (has(this, key)) return get(this, key);
  19. var value = callbackfn(key);
  20. set(this, key, value);
  21. return value;
  22. }
  23. });