Get-User-Locale

A function that returns user's locale as an IETF language tag, based on all available sources.

tl;dr

• Install by executing npm install get-user-locale or yarn add get-user-locale.
• Import by adding import getUserLocale from 'get-user-locale'.
• Do stuff with it!

  const userLocale = getUserLocale();

User guide

getUserLocale()

A function that returns user's preferred locale as an IETF language tag, based on all available sources.

Sample usage

import getUserLocale from 'get-user-locale';

getUserLocale(); // 'de-DE'

or

import { getUserLocale } from 'get-user-locale';

getUserLocale(); // 'de-DE'

Options

getUserLocale() may be called with an optional options argument.

options object may contain the following properties:

Property	Description	Default value
fallbackLocale	A locale to use as a fallback.	en-US
useFallbackLocale	Whether to use the fallback locale.	true

getUserLocales()

A function that returns an array of user's preferred locales as an IETF language tags, based on all available sources.

Sample usage

import { getUserLocales } from 'get-user-locale';

getUserLocales(); // ['de-DE', 'de', 'en-US', 'en']

Options

getUserLocales() may be called with an optional options argument.

options object may contain the following properties:

Property	Description	Default value
fallbackLocale	A locale to use as a fallback.	en-US
useFallbackLocale	Whether to use the fallback locale.	true

Technical details

There are a few ways of determining user's locale:

• window.navigator.languages
• window.navigator.language

…languages is an array of strings, …language is a string. Some browsers return mixed-case IETF language tags (e.g. de-DE), while others return lowercase ones (e.g. de-de). Finally, non-browser environments will not return anything, so you need a fallback.

Get-User-Locale does the following:

• Combines all of them into one sane set of locales - in that particular order,
• Dedupes them,
• Fixes invalid, lowercased IETF language tags (so that the part after - is always uppercased),
• Adds a fallback to en-US, so if all else fails, you will get a result that won't crash your app.

License

The MIT License.

Author

Wojciech Maj