ChatGPTgetChangesOnList.test.ts

import { getChangesOnList } from './getChangesOnList';

describe('getChangesOnList', () => {
  const prevList = [
    { id: 1, name: 'John' },
    { id: 2, name: 'Mary' },
    { id: 3, name: 'Bob' },
  ];
  const currList = [
    { id: 1, name: 'John' },
    { id: 2, name: 'Mary' },
    { id: 3, name: 'Robert' },
    { id: 4, name: 'Alice' },
  ];

  it('returns the correct changes when isEqual is not provided', () => {
    const changes = getChangesOnList(prevList, currList);

    expect(changes.add).toEqual([{ id: 4, name: 'Alice' }]);
    expect(changes.update).toEqual([{ id: 3, name: 'Robert' }]);
    expect(changes.remove).toEqual([]);
  });

  it('returns the correct changes when isEqual is provided', () => {
    const isEqual = (a: any, b: any) => a.id === b.id && a.name === b.name;
    const changes = getChangesOnList(prevList, currList, isEqual);

    expect(changes.add).toEqual([{ id: 4, name: 'Alice' }]);
    expect(changes.update).toEqual([{ id: 3, name: 'Robert' }]);
    expect(changes.remove).toEqual([]);
  });

  it('returns the correct changes when currList is empty', () => {
    const changes = getChangesOnList(prevList, []);

    expect(changes.add).toEqual([]);
    expect(changes.update).toEqual([]);
    expect(changes.remove).toEqual(prevList);
  });

  it('returns the correct changes when prevList is empty', () => {
    const changes = getChangesOnList([], currList);

    expect(changes.add).toEqual(currList);
    expect(changes.update).toEqual([]);
    expect(changes.remove).toEqual([]);
  });

  it('returns the correct changes when both lists are empty', () => {
    const changes = getChangesOnList([], []);

    expect(changes.add).toEqual([]);
    expect(changes.update).toEqual([]);
    expect(changes.remove).toEqual([]);
  });
});