ts-prime/src/groupBy.test.ts

A utility library for JavaScript and Typescript.

import { groupBy } from './groupBy';
import { pipe } from './pipe';

const array = [
  { a: 1, b: 1 },
  { a: 1, b: 2 },
  { a: 2, b: 1 },
  { a: 1, b: 3 },
] as const;
const expected = {
  1: [
    { a: 1, b: 1 },
    { a: 1, b: 2 },
    { a: 1, b: 3 },
  ],
  2: [{ a: 2, b: 1 }],
};

const employees = [
  {
    name: 'John',
    skills: ['Printing', 'Painting', 'Writing'],
  },
  {
    name: 'Britney',
    skills: ['Printing', 'Managing', 'Acting'],
  },
];
const expectedEmployees = {
  Printing: [
    {
      name: 'John',
      skills: ['Printing', 'Painting', 'Writing'],
    },
    {
      name: 'Britney',
      skills: ['Printing', 'Managing', 'Acting'],
    },
  ],
  Painting: [
    {
      name: 'John',
      skills: ['Printing', 'Painting', 'Writing'],
    },
  ],
  Managing: [
    {
      name: 'Britney',
      skills: ['Printing', 'Managing', 'Acting'],
    },
  ],
  Acting: [
    {
      name: 'Britney',
      skills: ['Printing', 'Managing', 'Acting'],
    },
  ],
  Writing: [
    {
      name: 'John',
      skills: ['Printing', 'Painting', 'Writing'],
    },
  ],
};

describe('data first', () => {
  test('groupBy', () => {
    expect(groupBy(array, x => x.a)).toEqual(expected);
  });
  test('groupBy multi keys', () => {
    expect(groupBy(employees, x => x.skills)).toEqual(expectedEmployees);
  });
  test('groupBy.indexed', () => {
    expect(groupBy.indexed(array, x => x.a)).toEqual(expected);
  });
  test('groupBy.indexed multi keys', () => {
    expect(groupBy.indexed(employees, x => x.skills)).toEqual(
      expectedEmployees
    );
  });
});

describe('data last', () => {
  test('groupBy', () => {
    expect(
      pipe(
        array,
        groupBy(x => x.a)
      )
    ).toEqual(expected);
  });
  test('groupBy multi keys', () => {
    expect(
      pipe(
        employees,
        groupBy(x => x.skills)
      )
    ).toEqual(expectedEmployees);
  });
  test('groupBy.indexed', () => {
    expect(
      pipe(
        array,
        groupBy.indexed(x => x.a)
      )
    ).toEqual(expected);
  });

  test('groupBy.indexed multi keys', () => {
    expect(
      pipe(
        employees,
        groupBy.indexed(x => x.skills)
      )
    ).toEqual(expectedEmployees);
  });
});