Custom Extractor

If your project is not working well with Lingui's Extractor, you can write your custom extractor implementation.

That might be the case if you use some experimental features (stage0 - stage2) or frameworks with custom syntax such as Vue.js or Svelte.

./my-custom-extractor.ts

import babel from "@lingui/cli/api/extractors/babel"

export const extractor: ExtractorType = {
  match(filename: string) {
      return filename.endsWith(".custom");
  },
  extract(filename: string, code: string, onMessageExtracted, ctx: ExtractorCtx) {
    // transform to plain JS + Sourcemaps
    const {code, sourcemaps} = transformMyCustomFileToJs(filename, code);

    // you can acess lingui config from using `ctx.linguiConfig`
    // reuse extractor from cli
    return babel(filename, code, onMessageExtracted, {sourcemaps, ...ctx})
  }
}

Then in your lingui.config.ts:

lingui.config.ts

import { extractor } from './my-custom-extractor.ts'
module.exports = {
  [...]
  extractors: [extractor]
}

Important

If you use TypeScript to create your extractor, you should use the ts extension for your Lingui configuration file.