@technobuddha/library/src/beginning-of-week.test.ts

A large library of useful functions

import { beginningOfWeek } from './beginning-of-week.ts';
import { month } from './date.ts';

describe('beginningOfWeek', () => {
  test('should find the beginning of the week', () => {
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18')).toString()).toBe(
      new Date('20 Jul 1969').toString(),
    );
  });

  test('should accept alternate start of week', () => {
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18'), { firstDayOfWeek: 0 }).toString()).toBe(
      new Date('20 Jul 1969').toString(),
    );
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18'), { firstDayOfWeek: 1 }).toString()).toBe(
      new Date('14 Jul 1969').toString(),
    );
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18'), { firstDayOfWeek: 2 }).toString()).toBe(
      new Date('15 Jul 1969').toString(),
    );
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18'), { firstDayOfWeek: 3 }).toString()).toBe(
      new Date('16 Jul 1969').toString(),
    );
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18'), { firstDayOfWeek: 4 }).toString()).toBe(
      new Date('17 Jul 1969').toString(),
    );
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18'), { firstDayOfWeek: 5 }).toString()).toBe(
      new Date('18 Jul 1969').toString(),
    );
    expect(beginningOfWeek(new Date('20 Jul 1969 20:18'), { firstDayOfWeek: 6 }).toString()).toBe(
      new Date('19 Jul 1969').toString(),
    );
  });

  test('should find the utc beginning of the week', () => {
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 20)).toString());
  });

  test('should accept alternate start of week with utc', () => {
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
        firstDayOfWeek: 0,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 20)).toString());
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
        firstDayOfWeek: 1,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 14)).toString());
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
        firstDayOfWeek: 2,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 15)).toString());
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
        firstDayOfWeek: 3,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 16)).toString());
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
        firstDayOfWeek: 4,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 17)).toString());
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
        firstDayOfWeek: 5,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 18)).toString());
    expect(
      beginningOfWeek(new Date(Date.UTC(1969, month.july, 20, 20, 18)), {
        utc: true,
        firstDayOfWeek: 6,
      }).toString(),
    ).toBe(new Date(Date.UTC(1969, month.july, 19)).toString());
  });
});