import insert from '../../utils/insert'; describe('insert', () => { it('should insert value at specific index in array', () => { expect(insert([1, 3, 4], 1, 2)).toEqual([1, 2, 3, 4]); expect( insert( [ { firstName: '1', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, { firstName: '2', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, { firstName: '4', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, ], 2, { firstName: '3', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, ), ).toEqual([ { firstName: '1', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, { firstName: '2', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, { firstName: '3', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, { firstName: '4', lastName: 'Luo', id: '75309979-e340-49eb-8016-5f67bfb56c1c', }, ]); }); it('should insert undefined as value when value to be inserted is falsy', () => { expect(insert([1, 2, 4], 2)).toEqual([1, 2, undefined, 4]); expect(insert([1, 2, 4], 2, 0)).toEqual([1, 2, 0, 4]); expect(insert([1, 2, 4] as (boolean | number)[], 2, false)).toEqual([ 1, 2, false, 4, ]); expect(insert([1, 2, 4] as (number | string)[], 2, '')).toEqual([ 1, 2, '', 4, ]); expect(insert([1, 2, 4], 2, undefined)).toEqual([1, 2, undefined, 4]); }); it('should spread value when it is an array at one deep-level', () => { expect(insert([1, 2], 2, [3, 4])).toEqual([1, 2, 3, 4]); expect(insert([1, 2], 2, [3, [4]])).toEqual([1, 2, 3, [4]]); }); });