v10: hooks and suspense

[jamuhl]

The plan is to provide both versions in the future:

• v10 will be the version having the new hooks and suspense version only
• v9 will be the last major version having the current react-i18next available (will go into maintenance mode -> only bug fixes - no new features)

We for sure will have to maintain v9 for a while.

TODO:

• rename useT -> useTranslation, withT -> withTranslations
• report namespaces functionality (auto enabled under the hood - accessible via getFunction)
• handle initialStore, initialLanguage (where? existing Hook, new explicit useSSRI18n Hook, new explicit withSSRI18n HOC)
• rename useReactI18n with useReactI18next here: https://github.com/i18next/react-i18next/blob/master/src/hooks/context.js#L35
• create a next.js sample as proof of concept: getInitialProps as a HOC, or just a plain function provided to get that values for initialI18nStore and initialLanguage from react-i18next? (useSSR for different requests #671 seems a prove of working as expected)
• add tests for all the new stuff
• add typings for typescript

Release winter 2018/19: https://reactjs.org/blog/2018/11/27/react-16-roadmap.html (won't be 16.7!!! https://reactjs.org/blog/2018/12/19/react-v-16-7.html)

Release seems to be 4th of February: facebook/react#14692

[schettino]

Is it going to be a full (or close to it) rewrite? Wanna give typescript a try 🚀 ? Either way, you can count on me to accomplish that!

[jamuhl]

@schettino will sleep over it...

[jamuhl]

@isaachinman made a suggestion for next.js / SSR in general:

all useTranslation report used namespaces: https://github.com/i18next/react-i18next/blob/master/src/hooks/useTranslation.js#L38

there is a new hook useSSR which enables passing initialI18nStore, initialLanguage which is used in the withSSR HOC which does two things:

1. use that useSSR hook to add those initial values on client side: https://github.com/i18next/react-i18next/blob/master/src/hooks/withSSR.js#L8 (does nothing than add store and lng to i18next like before - and asserts this gets done only once)

2. sets getInitialProps function on the Wrapped component: https://github.com/i18next/react-i18next/blob/master/src/hooks/withSSR.js#L15 -> that function can also be used for people prefer only using _app.js i guess: https://github.com/i18next/react-i18next/blob/master/src/hooks/context.js#L44

Not yet had time to make the exampe to validate the implementation - but would be sufficient to get your first opinion and change suggestions.

[isaachinman]

I like the context code, and especially like addUsedNamespaces in useTranslation. This is a great, simple solution.

As far as useSSR, the implementation looks reasonable, but I wonder why we need to have something called useSSR in the first place? It seems it's just to catch the initialLanguage, right?

[jamuhl]

yes useSSR is more or less a setInitialStore and setInitialLanguage (by calling i18n.changeLanguage) - i'm neither happy with the naming nor to much of exposing it...but using it in the HOC seems to have it seems reasonable -> but yes...naming it as a hook seems a little off - as it is just a function not a real hook -> so i'm open for suggestions.

[isaachinman]

Yes that makes sense. I don't think I made my other point as clear as it could be: what would prevent us from doing this useSSR step by default, so that it's one less thing users have to worry about? I am a big fan of SSR-by-default behaviour.

We could either pass default args into withSSR, or do some fallback/bail out inside the function itself, where we simply return the wrapped component if our initial setting needs aren't met.

Or maybe I am misunderstanding, and the withSSR HOC is only for internal use after all?

[jamuhl]

@isaachinman the useSSR is default in withSSR -> so withSSR is what using withI18next is today (with the only difference not giving you the t function).

the useSSR could be moved just into withSSR (i just thought having that for non next.js samples would / might make sense)

[zaguiini]

So, how is it going?

[jamuhl]

@zaguiini how is what going?

[zaguiini]

The typings for Typescript, mainly. I want to remove all those @ts-ignores from my code :D If I can help in any way...

[jamuhl]

ah...we not yet started with those honestly...there is as far as i know no eta for react 16.7 yet - so not the highest prio yet. If you like you might provide a PR so those typings will be ready when we can release v10.

@schettino not sure if you would prefer adding those or your ok with reviewing a PR from @zaguiini ?!