example.js

import {getCurrentWeek} from 'weekSolution';

// Friday: -2
getCurrentWeek(-2)

// Saturday: -1
getCurrentWeek(-2)

// Sunday: 0
getCurrentWeek(0)

// Monday: 1
getCurrentWeek(1)

// Tuesday: 2
getCurrentWeek(2)

// Wednesday: 3
getCurrentWeek(3)

// Thursday: 4
getCurrentWeek(4)

weekSolution.js

import moment from 'moment';

moment.defineLocale('custom-0', {parentLocale: 'en', week:{dow : 0}});
moment.defineLocale('custom-1', {parentLocale: 'en', week:{dow : 1}});
moment.defineLocale('custom-2', {parentLocale: 'en', week:{dow : 2}});
moment.defineLocale('custom-3', {parentLocale: 'en', week:{dow : 3}});
moment.defineLocale('custom-4', {parentLocale: 'en', week:{dow : 4}});
moment.defineLocale('custom--2', {parentLocale: 'en', week:{dow : -2}});
moment.defineLocale('custom--1', {parentLocale: 'en', week:{dow : -1}});



export function getCurrentWeek(dayOffSet) {
  moment.locale(`custom-${dayOffSet}`) //always set this to override locale settings.
  let date = moment()
  return {
    year: date.year(),
    week: date.week()
  };
};