How to get month list in your locale

#javascript #typescript #localization #webdev

Hi there! I am glad to show simple TypeScript function, that maybe will save your time. In many cases you need to implement selector of months. In some cases it should be in different locales. See it below:

function getMonthList(
  locales?: string | string[],
  format: "long" | "short" = "long"
): string[] {
  const year = new Date().getFullYear(); // 2020
  const monthList = [...Array(12).keys()]; // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]
  const formatter = new Intl.DateTimeFormat(locales, {
    month: format
  });

  const getMonthName = (monthIndex: number) =>
    formatter.format(new Date(year, monthIndex));

  return monthList.map(getMonthName);
}

That's it. Just provide your locale as param.
For example, 🇬🇧 getMonthList('en') will return:

January
February
March
April
May
June
July
August
September
October
November
December

Try it by yourself on codesandbox.

For short version of names just provide second param as short.
For example, 🇬🇧 getMonthList('en', 'short') will return:

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Follow me in Twitter

Update
By your requests I have extracted function in package

Top comments (9)

Maksim • Jun 4 '20

Thanks, fixed

asdsadasf • Jun 9 '20

Hi, great article, thanks.

Which part of this code is typescript, It's like all javascript to me, but some parts seems strange. Maybe those parts, lol?

Maksim • Jun 9 '20

Thank you! JavaScript version:

function getMonthList(locales, format = "long") {
  const year = new Date().getFullYear(); // 2020
  const monthList = [...Array(12).keys()]; // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]
  const formatter = new Intl.DateTimeFormat(locales, {
    month: format
  });

  const getMonthName = (monthIndex) =>
    formatter.format(new Date(year, monthIndex));

  return monthList.map(getMonthName);
}

Danny Engelman • Jun 9 '20 • Edited

Using the 2nd parameter mapFn on Array.from instead of .map saves a spread on monthList

function getMonthList(locales, format = "long") {
  const year = new Date().getFullYear(); // 2020
  const monthList = Array(12).keys(); // an Array Iterator
  const formatter = new Intl.DateTimeFormat(locales, {
    month: format
  });
  const getMonthName = (monthIndex) =>  formatter.format(new Date(year, monthIndex));

  return Array.from(monthList , getMonthName);
}

```

`

Danny Engelman • Jun 9 '20 • Edited

And since year is not a parameter, no need for const year declaration to get a monthname

new Date(0, monthIndex) will do, for ES Arrow function:

const getMonthList = (locale = "en", notation = "long" ) =>
  Array.from(
    Array(12).keys(),
    key => Intl.DateTimeFormat(locale, {
      month: {
         s : "short",
         n : "numeric"
      } [notation[0]] || "long"
    })
    .format(new Date(0, key))
  );
```

`