1. /**
    
  2.  * Copyright (c) Meta Platforms, Inc. and affiliates.
    
  3.  *
    
  4.  * This source code is licensed under the MIT license found in the
    
  5.  * LICENSE file in the root directory of this source tree.
    
  6.  *
    
  7.  * @emails react-core
    
  8.  */
    
  9. 'use strict';
    
  10. 
    
  11. describe('ReactSymbols', () => {
    
  12.   beforeEach(() => jest.resetModules());
    
  13. 
    
  14.   const expectToBeUnique = keyValuePairs => {
    
  15.     const map = new Map();
    
  16.     keyValuePairs.forEach(([key, value]) => {
    
  17.       if (map.has(value)) {
    
  18.         throw Error(
    
  19.           `${key} value ${value.toString()} is the same as ${map.get(value)}.`,
    
  20.         );
    
  21.       }
    
  22.       map.set(value, key);
    
  23.     });
    
  24.   };
    
  25. 
    
  26.   it('Symbol values should be unique', () => {
    
  27.     expectToBeUnique(Object.entries(require('shared/ReactSymbols')));
    
  28.   });
    
  29. });