getTimeGreetings

getTimeGreetings.test.ts

import { getTimeGreetings, welcomes } from '.';

describe('getTimeGreetings', () => {
  beforeEach(() => {
    jest.useFakeTimers();
  });

  it('should return night greetings', () => {
    jest.setSystemTime(
      new Date('Thu Oct 06 2022 00:00:54 GMT-0400 (Eastern Daylight Time)')
    );

    expect(getTimeGreetings()).toBe(welcomes.night);
  });

  it('should return morning greetings', () => {
    jest.setSystemTime(
      new Date('Thu Oct 06 2022 08:29:54 GMT-0400 (Eastern Daylight Time)')
    );

    expect(getTimeGreetings()).toBe(welcomes.morning);
  });

  it('should return afternoon greetings', () => {
    jest.setSystemTime(
      new Date('Thu Oct 06 2022 15:29:54 GMT-0400 (Eastern Daylight Time)')
    );

    expect(getTimeGreetings()).toBe(welcomes.afternoon);
  });

  it('should return evening greetings', () => {
    jest.setSystemTime(
      new Date('Thu Oct 06 2022 19:29:54 GMT-0400 (Eastern Daylight Time)')
    );

    expect(getTimeGreetings()).toBe(welcomes.evening);
  });
});

getTimeGreetings.ts

export const welcomes = {
  morning: 'Доброе утро',
  afternoon: 'Добрый день',
  evening: 'Добрый вечер',
  night: 'Доброй ночи',
};

/**
 * This function gets time of day greetings
 */
export const getTimeGreetings = () => {
  const hour = new Date().getHours();

  if (hour < 6) {
    return welcomes.night;
  }

  if (hour < 12) {
    return welcomes.morning;
  }

  if (hour < 18) {
    return welcomes.afternoon;
  }

  return welcomes.evening;
};