makeReadOnly-test.ts — react Source File

Source Code

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

import buildMakeReadOnly from '../makeReadOnly';

describe('makeReadOnly', () => {
  let logger: jest.Func;
  let makeReadOnly: <T>(value: T, source: string) => T;

  beforeEach(() => {
    logger = jest.fn();
    makeReadOnly = buildMakeReadOnly(logger, []);
  });

  describe('Tracking mutations', () => {
    it('can be called with all primitives', () => {
      const a = 5;
      const b = true;
      const c = null;
      expect(makeReadOnly(a, 'test1')).toBe(a);
      expect(makeReadOnly(b, 'test1')).toBe(b);
      expect(makeReadOnly(c, 'test1')).toBe(c);
    });

    it('retains referential equality', () => {
      const valA = {};
      const valB = {a: valA, _: valA};
      const o = {a: valA, b: valB, c: 'c'};
      expect(makeReadOnly(o, 'test2')).toBe(o);
      expect(makeReadOnly(o.a, 'test2')).toBe(valA);
      expect(makeReadOnly(o.b, 'test2')).toBe(valB);
      expect(makeReadOnly(o.b.a, 'test2')).toBe(valA);
      expect(makeReadOnly(o.b._, 'test2')).toBe(valA);
      expect(makeReadOnly(o.c, 'test2')).toBe('c');
    });

    it('deals with cyclic references', () => {
      const o: any = {};
      o.self_ref = o;
      expect(makeReadOnly(o, 'test3')).toBe(o);
      expect(makeReadOnly(o.self_ref, 'test3')).toBe(o);
    });
    it('logs direct interior mutability', () => {
      const o = {a: 0};
      makeReadOnly(o, 'test4');
      o.a = 42;
      expect(logger).toBeCalledWith('FORGET_MUTATE_IMMUT', 'test4', 'a', 42);
    });

    it('tracks changes to known RO properties', () => {
      const o: any = {a: {}};
      makeReadOnly(o, 'test5');
      o.a = 42;
      expect(logger).toBeCalledWith('FORGET_MUTATE_IMMUT', 'test5', 'a', 42);
      expect(o.a).toBe(42);
      const newVal = {x: 0};
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