Fallback

Often, translations lag behind the source code. And it is necessary to make sure that the user sees at least the English version of the message, instead of some meaningless text. For example, for the following code:

<p>Hello</p>

When it is extracted initially, it becomes the following for other languages:

msgid "Hello"
msgstr ""

Then during compile time, if the text has not yet been translated, it looks for the first translation along a fallback chain. With no configuration, for locales that are regional variants like fr-CH, it falls back to the base one fr. And explicit chains can be configured by providing from-to pairs in the fallback key. Finally, the end of the chain is the source locale. For example, with a config like this:

wuchale.config.js

export default {
  // ...
  fallback: {
    "fr-CH": "fr-FR",
    "fr-FR": "fr-ES",
  },
  // ...
};

The fallback chain for fr-CH (with en as the source locale) would be:

1. fr-FR
2. fr-ES
3. fr
4. en