Providing i18n translations for (custom) audits

Inject Translations for custom audits

There is currently no information in the docs on how to add I18N translations for locales for a custom audit.

I have a custom audit like the one below and want to provide a translation for a given locale (let’s say ‘fr’). How to proceed? How to inject or reference a json file with my custom translations for several locales?

'use strict';
const Audit = require('lighthouse').Audit;
const i18n = require('lighthouse/lighthouse-core/lib/i18n/i18n.js');

const UIStrings = {
  title: 'A crazy audit',
  failureTitle: 'Audit failed massively',
  description: 'This is a test. This is not real. ',
};

const str_ = i18n.createMessageInstanceIdFn(__filename, UIStrings);

class MyCustomAudit extends Audit {
  static get meta() {
    return {
      id: 'my-custom-audit',
      title: str_(UIStrings.title),
      failureTitle: str_(UIStrings.failureTitle),
      description: str_(UIStrings.description),
    };
  }

  static audit(artifacts) {
    [...]
  }
}

module.exports = MyCustomAudit;

There also sees to be no way to provide another JSON files as extension to the existing locale files in lighthouse-core to overwrite an existing translation or to provide a missing translation during runtime without touching core files.

[fbatschi]

The reason for us to override core translations is that some of the translations are too technical for our audience of the reports, so we want to change them completely (during runtime), in other cases we simply wanted to add a sentence or two.

For the time being we have built the functionality with a handful of new lines of code to i18n.js as well as including the y18n package and preserve the changes with patch-package to enable both requested features for us.

If translations for custom audits become a core feature though, this would be appreciated.

[paulirish]

Update: We introduced a i18n.registerLocaleData() method in https://github.com/GoogleChrome/lighthouse/pull/9638 We didn’t intend for it to be used outside of the Lighthouse internals, but it certainly could be.

We still don’t offer a first-class i18n story for custom audits.