[Discussion] angular-cli and i18n (ng-xi18n + ngc)

With angular's i18n working quite good now, I wanted to start a general discussion about how the angular-cli will be supposed to work with it.

According to this statement on StackOverflow from @Brocco, angular-cli will eventually make use of AOT compilation. This means, that ngc will be used, which in turn will respect xlf files for translations. For JIT builds (development builds), we could make use of a raw webpack loader, which loads a xlf file as string and provides this as translation.

Here are some questions which come to my mind and I think need to be considered in future development:

• Currently, for a production build, everything (vendor's code + application code) is bundled into one single bundle.js file. With multiple translations, will we be supposed to have one complete bundle for each language? This seems to be a very inpractical approach. Bundling every translation into the bundle.js is not practical either, as in maybe 99% of all cases, one language is sufficient. Imagine a popular app, built with angular, which is used from people all over the world. We 1) don't want to ship a bundle.js containing all possible translations, because eventually they will blow up the bundle size. We 2) don't want to have hundrets of bundles, each for one language. Maybe it would be good to split the bundle.js into two separate bundles: 1) vendors library code, 2) NgFactory code. For each language, a dedicated ngfactory-bundle.lang-LANG.js would then be created.
• What about libraries that support localization? For example a library which supplies some input components (like a calendar) which needs to be localized.
• How can we reliably detect the language and load the app accordingly? At the moment, this has to occur during bootstrap, but what about detecting the browser locale or maybe the users preference (this means: much later than bootstrap time; after a database request, fetching the user settings after auth)?
• As ng is a façade: would we need an ng i18n command to hide the possibly rather complex ng-xi18n call (regarding hiding passed parameters... a call could otherwise look like this: ./node_modules/.bin/ng-xi18n -p src/tsconfig.json ......)? Or could this be automated with some kind of watch (I don't think so, as ng-xi18n takes some time to complete, even with a small app)?
• Where would we store the localization files? Maybe src/i18n/ would be a good place for the start. If we would like to encourage a set of localization files for each module, it should be located at src/<module-name>/i18n/ or maybe src/i18n/<module-name>/. The latter approach would be better for translator-teams, or translation-tools I think

[elvirdolic]

As we have now AOT in angular-cli the question is how we can use i18n with aot and CLI? At the moment I don't see the possibility.

@christiandreher already said this is a common case for apps to support multiple languages and I think it would be a great experience to have this in CLI to make the experience complete or at least some instructions how that can be achieved outside of CLI magic blackbox.

[filipesilva]

This is something we'd like to have, but there's still a fair bit of architecture discussion around it that we need to do before getting to it.

[mbeckenbach]

@elvirdolic That would be great for the moment.

least some instructions how that can be achieved outside of CLI magic blackbox.

I've got a fully automated set of gulp tasks to create XLF files, merge to translation files, etc. Please see my blog: http://rolandoldengarm.com/index.php/2016/10/17/angular-2-automated-i18n-workflow-using-gulp/
Only tested with JIT, but I think it will work for AOT as well.

[kemsky]

Is it possible to use i18n with angular-cli now?

@kemsky yes, we're using i18n + Angular CLI.

[jfmaeck]

@rolandoldengarm are you using i18n + Angular CLI + Ahead of Time Compilation? If so, I would very much appreciate any hints on how to get this working.

For people struggling with i18n + Angular CLI: It took me a while to figure out the correct way to call ng-xi18n (although it is mentioned in this issue's description, actually):

./node_modules/.bin/ng-xi18n -p src/tsconfig.json

Or in package.json:

  ...
  "scripts": {
    "i18n": "ng-xi18n -p src/tsconfig.json"
  }
  ...

@jfmaeck just scroll up a bit... #2201 (comment)

[kemsky]

@jfmaeck, thanks for tsconfig.json tip.

@rolandoldengarm, it works in JIT mode, but in AOT bootstrapModule is replaced by bootstrapModuleFactory automatically, i see i18n providers are passed but localization does not work.

[serhiisol]

@jfmaeck With this option i got this message

Error: Error Unknown compiler option 'include'.
    at check (/Users/serhiysolonko/Development/monorepo/website/node_modules/@angular/tsc-wrapped/src/tsc.js:31:15)
    at Tsc.readConfiguration (/Users/serhiysolonko/Development/monorepo/website/node_modules/@angular/tsc-wrapped/src/tsc.js:66:9)
    at Object.main (/Users/serhiysolonko/Development/monorepo/website/node_modules/@angular/tsc-wrapped/src/main.js:17:28)
    at Object.<anonymous> (/Users/serhiysolonko/Development/monorepo/website/node_modules/@angular/compiler-cli/src/extract_i18n.js:46:9)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.runMain (module.js:604:10)
Extraction failed