Internationalization (i18n)

Why isn't i18n Supported by Default?

The default Javet releases don't support i18n for the following reasons.

  • Tens of MBs can be saved.

  • Performance is slightly better.

  • No additional deployment is required.

How to Enable i18n?

  • Follow Installation to turn i18n on.

  • Download and save icudt*.dat files from somewhere to a local directory. E.g. v8/third_party/icu, node/deps/icu-tmp.

Note

There are 2 typical ways of getting the i18n files.

  1. Clone Node.js or V8, then copy the files over.

  2. Visit Actions, then download the files from the latest successful builds.

  • Set a flag as follows before the first Node.js or V8 runtime is created.

// Node.js Mode
NodeRuntimeOptions.NODE_FLAGS.setIcuDataDir("/dir/of/the/icudt*.dat");
// Note: It must be a directory.

// V8 Mode
V8RuntimeOptions.V8_FLAGS.setIcuDataFile("/path/of/the/icudt*.dat");
// Note: It must be a file.

Let's Go!

Node.js Mode

File icuDataDir = new File(JavetOSUtils.WORKING_DIRECTORY)
        .toPath()
        .resolve("../node/deps/icu-tmp")
        .normalize()
        .toFile();
NodeRuntimeOptions.NODE_FLAGS.setIcuDataDir(icuDataDir.getAbsolutePath());
try (NodeRuntime nodeRuntime = V8Host.getNodeI18nInstance().createV8Runtime()) {
    System.out.println(nodeRuntime.getExecutor("const a = 123456; a.toLocaleString('en-US');").executeString());
    // 123,456
    System.out.println(nodeRuntime.getExecutor("const us = new Intl.Locale('en-US'); us.language;").executeString());
    // en
    System.out.println(nodeRuntime.getExecutor("JSON.stringify(['Z', 'a', 'z', 'ä'].sort(new Intl.Collator('de').compare));").executeString());
    // ["a","ä","z","Z"]
}

V8 Mode

File icuDataFile = new File(JavetOSUtils.WORKING_DIRECTORY)
        .toPath()
        .resolve("../google/v8/third_party/icu/common/icudtl.dat")
        .normalize()
        .toFile();
V8RuntimeOptions.V8_FLAGS.setIcuDataFile(icuDataFile.getAbsolutePath());
try (V8Runtime v8Runtime = V8Host.getV8I18nInstance().createV8Runtime()) {
    System.out.println(v8Runtime.getExecutor("const a = 123456; a.toLocaleString('en-US');").executeString());
    // 123,456
    System.out.println(v8Runtime.getExecutor("const us = new Intl.Locale('en-US'); us.language;").executeString());
    // en
    System.out.println(v8Runtime.getExecutor("JSON.stringify(['Z', 'a', 'z', 'ä'].sort(new Intl.Collator('de').compare));").executeString());
    // ["a","ä","z","Z"]
}