Human code

getChangesOnList.test.ts

import { getChangesOnList } from './getChangesOnList';

describe('getChangesOnList', () => {
  type TestItem = { id: number; value: string };

  const testItemA: TestItem = { id: 1, value: 'A' };
  const testItemB: TestItem = { id: 2, value: 'B' };
  const testItemC: TestItem = { id: 3, value: 'C' };

  const testItems: TestItem[] = [testItemA, testItemB, testItemC];

  it('should return the expected changes when the lists are the same', () => {
    expect(getChangesOnList(testItems, testItems)).toEqual({
      add: [],
      update: [],
      remove: [],
    });
  });

  it('should return the expected changes when the lists are the same but in a different order', () => {
    expect(
      getChangesOnList([testItemA, testItemB], [testItemB, testItemA])
    ).toEqual({
      add: [],
      update: [],
      remove: [],
    });
  });

  it('should return the expected changes when the lists are different', () => {
    expect(
      getChangesOnList([testItemA, testItemB], [testItemA, testItemC])
    ).toEqual({
      add: [testItemC],
      update: [],
      remove: [testItemB],
    });
  });

  it('should return the expected changes when an item has been updated', () => {
    expect(
      getChangesOnList(
        [testItemA, testItemB],
        [{ ...testItemA, value: 'A_updated' }, testItemB]
      )
    ).toEqual({
      add: [],
      update: [{ ...testItemA, value: 'A_updated' }],
      remove: [],
    });
  });

  it('should return updates for nested objects', () => {
    expect(
      getChangesOnList(
        [{ ...testItemA, nested: { value: 'A' } }],
        [{ ...testItemA, nested: { value: 'A_updated' } }]
      )
    ).toEqual({
      add: [],
      update: [{ ...testItemA, nested: { value: 'A_updated' } }],
      remove: [],
    });
  });

  it('should return updates for nested arrays', () => {
    expect(
      getChangesOnList(
        [{ ...testItemA, nested: [{ value: 'A' }] }],
        [{ ...testItemA, nested: [{ value: 'A_updated' }] }]
      )
    ).toEqual({
      add: [],
      update: [{ ...testItemA, nested: [{ value: 'A_updated' }] }],
      remove: [],
    });
  });

  it('should return updates for nested arrays with objects', () => {
    expect(
      getChangesOnList(
        [{ ...testItemA, nested: [{ value: 'A' }] }],
        [{ ...testItemA, nested: [{ value: 'A_updated' }] }]
      )
    ).toEqual({
      add: [],
      update: [{ ...testItemA, nested: [{ value: 'A_updated' }] }],
      remove: [],
    });
  });
});