feat(service): hideBeforeDisplay

[rbalet]

Description

Enable the possibility to hide the keys before they have been translated.

• closed: Hide translation labels until language file is loaded #689

[rbalet]

@CodeAndWeb Note, I can also do the directive, just didn't wanted to add more time if you wouldn't accept this one or if you have a better implementation

[CodeAndWeb]

I think this solution is incomplete: It does not work for - e.g. instant() or directives.

A more complete solution might be to use a MissingTranslationHandler instead. E.g. we could create a

export class SilentMissingTranslationHandler implements MissingTranslationHandler {
    handle(params: MissingTranslationHandlerParams): string {
        return "";
    }
}

and replace it with the "real" one after the first language or fallback language was loaded. I'd prefer this solution since it's more in one place instead of implementing the logic in several places.

Uses could also easily use a handler like this themselves.
It's also possible to register to onLangChange() and update the flag to show the translation keys.

[rbalet]

@CodeAndWeb yes you're right and I like the idea :). Shall I let you implement it, as you're more familiar with the missing handler?

If not you can assign it to me and I'll look into it

[CodeAndWeb]

It's already implemented and documented, see

https://ngx-translate.org/recipes/fix-translation-loading-glitches/#solution-3-custom-missingtranslationhandler-for-empty-strings

[rbalet]

@CodeAndWeb Indeed, we already have workaround, but this implementation will let you delete the entire page, which is quite long, in favour of a simple hideBeforeDisplay: true settings.

Or what is going against it ?

[CodeAndWeb]

It does not replace the page. Options 1 and 2 are valid solutions to the problem, too - maybe even better than displaying an empty text - which event might introduce bigger content shift after the strings are loaded.
It puts more weight on our shoulders for a solution that can be solved with minimum effort.

What I would accept is adding a useEmptyStringIfNotFound or similar as parameter for the MissingTranslationHandler.
That has the same effect and keeps the changes to a minimum.