This folder contains a sample VS code extension that shows how to use the package.nls.json and the vscode-nls library for localization. For this sample, it shows two commands: Hello and Bye in English and Japanese.

Assumptions

All localization files are under the i18n folder.
You could have created this folder by hand, or you could have used the vscode-nls-dev tool to extract it.
Under the i18n folder, you have sub-folders that represent the language you want to localize. These names follow the ISO 639-3 convention.
Under the language names folder you will create json files that mirror the structure of the source code for your extension (e.g., out/src). The json files are key:value pairs of the text that you want to localize. The naming convention is <file_name>.i18n.json.
If you have a top-level package.nls.json file in your extension, you should have one for each language following the naming convention of package.i18n.json.

Demo

Running the Sample

Localization values are only applied when running the gulp build task. During normally development which uses tsc -watch to compile no localization post processing happens. This speeds up development time.

Ensure that you have gulp-cli installed globally using npm install --global gulp-cli.
Run npm install to bring in the dependencies.
Follow the steps at https://code.visualstudio.com/api/working-with-extensions/publishing-extension to ensure that you have installed vsce and have a publisher account.
Run gulp package to produce a .vsix file.
Install the .vsix file following the instructions at https://code.visualstudio.com/docs/editor/extension-gallery#_install-from-a-vsix
Change your locale to Japanese by invoking "Configure Language" from the Command Palette.

See the demo.gif file in this repository for a screencast.

How to translate our extension

VS Code doesn't recommend a translation platform. None of the nls tooling provided by vscode-nls or vscode-nls-dev requires a specific translation platform. So you are free to choose the one you like.

What happens behind the scenes

The vscode-nls-dev module is used to rewrite the generated JavaScript.
Calls of the form localize('some_key', 'Hello') are transformed to localize(0, null) where the first parameter (0, in this example) is the position of the key in your messages file.
The contents of the i18n folder are transformed from key:value pairs into positional arrays.

Considerations

It is possible to use your own localization pipeline.

Localizations in your package.json can be done by wrapping the localized text in the form %some.key%.

// [Before] package.json

  "contributes": {
    "commands": [
      {
        "command": "extension.sayHello",
        "title": "Hello"
      }
    ]

// [After] package.json

  "contributes": {
    "commands": [
      {
        "command": "extension.sayHello",
        "title": "%extension.sayHello.title%"
      }
    ]

// [After] new package.nls.json

{
    "extension.sayHello.title": "Hello",
}

Then, create the corresponding package.nls.{your_language}.json files for each language to localize.

It is also possible to use your own library for localizing text in your source file. You would use the value of process.env.VSCODE_NLS_CONFIG environment variable. At runtime, this environment variable is a JSON string that contains the locale that VS Code is run with. For instance, this is the value for Japanese: "{"locale":"ja","availableLanguages":{"*":"ja"}}"


function localize(config) {
  const messages = {
    en: 'Hello',
    ja: 'こんにちは'
  };
  return messages[config['locale']];
}

const config = JSON.parse(process.env.VSCODE_NLS_CONFIG);
localize(config);