[WIP] docs(guide): document internationalization (i18n)

[ocombe]

Hello !

Here is the dev guide for internationalization (i18n).

This is my first guide, which means that there are probably a lot of things to improve ! And since I'm french, there might be typos and weird sentences, don't hesitate to tell me what should be changed :-)

edit: @Foxandxss told me that I should add an application with a story, I'll be working on that

[vicb]

remove

[Foxandxss]

We are using it in all examples, I think it has to do with ts-node to be able to understand a few things.

[vicb]

Would be nice to add a short text about placeholders:

<p i18n>this is <b>bold</b></p>
<p i18n>this is an {{ exp }}</p>

[feloy]

@ocombe First, thanks for this doc.

It could be interesting that you speak about the i18n-placeholder directive (and some others that I could not know).

For information, I've implemented i18n in this app with the help of your doc (ng2-rc.7, angular-cli webpack.9-4): https://github.com/actimeo/simmage-ui

It is not very clear how to choose the language at bootstrap time. I've made a first try with some quick hack to get the language from local storage.

[ocombe]

@feloy there will be a complete example added that should help you to know how to select the language at setup
Also what is the "i18n-placeholder" ? it's nowhere in the source of angular

[feloy]

I've found the code here:
https://github.com/angular/angular/blob/master/modules/%40angular/compiler/src/i18n/extractor_merger.ts#L314

In fact it is possible to mark any translatable attribute, e.g. i18n-placeholder to mark to translate the placeholder one.

[ocombe]

Interesting, thanks, I'm not sure if it is intended though, this might be something that could change later and you shouldn't rely on it
What do you think @vicb ?

[Foxandxss]

Continuing in #2340

[vicb]

wahou what happens, too many francais here ;)

[vicb]

Yep i18n-<attrName> is working and here to stay.