react-day-picker/src/labels/labelWeekday.test.ts

Customizable Date Picker for React

import { es } from "date-fns/locale/es";

import { labelWeekday } from "./labelWeekday";

const weekDay = new Date(2022, 10, 21);

test("should return the formatted weekday name", () => {
  expect(labelWeekday(weekDay)).toEqual("Monday");
});

describe("when a locale is passed in", () => {
  test("should format using the locale", () => {
    expect(labelWeekday(weekDay, { locale: es })).toEqual("lunes");
  });
});