Missing locale data for: "en-US". Using default locale: "en" as fallback.

[catamphetamine]

[React Intl] Missing locale data for: "en-US". Using default locale: "en" as fallback.

[catamphetamine]

I found the cause of the error:

<IntlProvider locale={locale} messages={messages}>

It doesn't support a properly formatted locale.

A workaround:

function get_language(locale)
{
    const dash_index = locale.indexOf('-')
    if (dash_index >= 0)
    {
        return locale.substring(0, dash_index)
    }
    return locale
}

// not real locale
<IntlProvider locale={get_language(locale)} messages={messages}>

[ericf]

You'll need to load locale-data/en.js to get support for en-US. By default only the root, en locale data is provided.

It doesn't support a properly formatted locale.

This is incorrect. The locale data files are provide per language, e.g. en.js, but they contain data for all locales in that language, e.g. en-US, en-GB, etc.

[SachaG]

I just ran into this issue. So just to clarify, in the following snippet fr works but fr_FR doesn't:

import fr from 'react-intl/locale-data/fr';
import { addLocaleData } from 'react-intl';
addLocaleData([...fr]);
...
<IntlProvider locale="fr" messages={myStrings}>

Is that the expected behavior? What would I need to do if I did want to use fr_FR or fr_CA instead?

[ericf]

@SachaG The locale needs to be a BCP-47 language tag. Replace _ with -.

[mccrodp]

Hey @ericf, thanks for your answers. I am getting this in Gatsby w/ community i18n plugin. I have added the locale-data as you can see here, but I still get the below error. Any more specific ideas to what is missing? I have only de and en-US langs set, no en at the moment as it's not my repo.

commons.js:77217 [React Intl] Missing message: "selectLanguage" for locale: "en-US"
commons.js:77217 [React Intl] Missing message: "selectLanguage" for locale: "de"
commons.js:77217 [React Intl] Missing message: "selectLanguage" for locale: "en"

This seems to be workign now via:

import { addLocaleData } from 'react-intl';

import en from 'react-intl/locale-data/en';
import 'intl/locale-data/jsonp/en';

addLocaleData(en); // It seems this also adds "en-US" locale?