recoil/cjs/core/__tests__/Recoil_batcher-test.js.flow

Recoil - A state management library for React

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @emails oncall+recoil
 * @flow strict-local
 * @format
 */
'use strict';

const {
  getRecoilTestFn
} = require('../../testing/Recoil_TestingUtils');

let unstable_batchedUpdates, batchUpdates, getBatcher, setBatcher;
const testRecoil = getRecoilTestFn(() => {
  ({
    unstable_batchedUpdates
  } = require('ReactDOM'));
  ({
    batchUpdates,
    getBatcher,
    setBatcher
  } = require('../Recoil_Batching'));
});
/**
 * Cleanup function that will reset the batcher back
 * to ReactDOM's resetBatcherToDefault.
 *
 * Call this at the end of a test that calls setBatcher
 * to maintain test purity.
 */

declare var resetBatcherToDefault: () => any;
describe('batcher', () => {
  testRecoil('default batcher is ReactDOM unstable_batchedUpdates', () => {
    expect(getBatcher()).toEqual(unstable_batchedUpdates);
  });
  testRecoil('setBatcher sets the batcher function', () => {
    const batcherFn = jest.fn();
    setBatcher(batcherFn);
    expect(getBatcher()).toEqual(batcherFn);
    resetBatcherToDefault();
  });
  testRecoil('batchUpdates calls the batcher', () => {
    const batcherFn = jest.fn();
    setBatcher(batcherFn);
    batchUpdates(() => {});
    expect(batcherFn).toHaveBeenCalledTimes(1);
    resetBatcherToDefault();
  });
});