frontend/src/common/datetime/localize_date.ts

import memoizeOne from "memoize-one";

export const localizeWeekdays = memoizeOne(
  (language: string, short: boolean): string[] => {
    const days: string[] = [];
    const format = new Intl.DateTimeFormat(language, {
      weekday: short ? "short" : "long",
      timeZone: "UTC",
    });
    for (let i = 0; i < 7; i++) {
      const date = new Date(Date.UTC(1970, 0, 1 + 3 + i));
      days.push(format.format(date));
    }
    return days;
  }
);

export const localizeMonths = memoizeOne(
  (language: string, short: boolean): string[] => {
    const months: string[] = [];
    const format = new Intl.DateTimeFormat(language, {
      month: short ? "short" : "long",
      timeZone: "UTC",
    });
    for (let i = 0; i < 12; i++) {
      const date = new Date(Date.UTC(1970, 0 + i, 1));
      months.push(format.format(date));
    }
    return months;
  }
);