Exception on not existing key or value - is this the wanted behavior?

[ilanbm]

If a key does not exist in the namespace, or if the value is empty, t function raises an exception.

The key can be debatable, but why would an empty value raise an exception?

Is there a default value to set if there is no key/value?

[amannn]

Thanks for the report!

If a key does not exist in the namespace

Do you mean a scenario like this?

function Component() {
  const t = useTranslations('Component');

  return <Text>{t('nonExistingKey')}</Text>
}

// en.json
{
  "Component": {
    "existingKey": "Hello"
  }
}

Currently next-intl would throw here and I think that's helpful to fix the error. What would be your expected behaviour?

if the value is empty

That's true, I guess we could avoid the error here. However I'm wondering when you'd practically want to use an empty label? Why would you want a translation for that? Isn't this a situation where the developer might has forgot to set up a message?

Is there a default value to set if there is no key/value?

What would you want to put there? Something like "Sorry, no translation available currently."? I'm wondering if that's really helpful to the user. If you have a locale where you haven't completed all translations yet, you could deep merge messages from the default locale to have a fallback (if this is desired – you wouldn't get errors for missing translations then).

[ilanbm]

Currently next-intl would throw here and I think that's helpful to fix the error. What would be your expected behaviour?

Well I think it is wrong to consider that an error, not having a key is legit. It is not code, it can come from various sources and in different languages.
Besides that, its ok not to have a key and expect a predefined default value (that's the common case in most of the other libraries)

That's true, I guess we could avoid the error here. However I'm wondering when you'd practically want to use an empty label? Why would you want a translation for that? Isn't this a situation where the developer might has forgot to set up a message?

Nope, you can't narrow it to a case where a developer/translator forgot to set a value to a key, there are various scenarios of having a wanted empty value. It caused me to look for workarounds here, ended using a transparent char... it my case some keys in some languages don't have a known translation so if there is no value I use the English translation. So having an empty value is a wanted scenario.

What would you want to put there? Something like "Sorry, no translation available currently."? I'm wondering if that's really helpful to the user. If you have a locale where you haven't completed all translations yet, you could deep merge messages from the default locale to have a fallback (if this is desired – you wouldn't get errors for missing translations then).

Keep it simple and predictable, return exactly what it is: an empty string.

[ilanbm]

I have also lots of cases where the empty value is there until translated in the future (where the English texts are not final, but are live. and I expect showing nothing at that paragraph in another language until it will be translated in the future.

[ilanbm]

(empty is not a bug, its a feature) :)

[amannn]

Thanks for explaining! Well I guess it's ok to accept empty messages, since as you explained it's quite explicit. I'll add a PR for this.

Besides that, its ok not to have a key and expect a predefined default value (that's the common case in most of the other libraries)

Do you have a link that describes this feature in other libraries? For the missing key I feel stronger about keeping the error.

it my case some keys in some languages don't have a known translation so if there is no value I use the English translation. So having an empty value is a wanted scenario.

You can use fallback messages from a different locale like this:

const messages = deepMerge(defaultMessages, userLocaleMessages);

[amannn]

This is fixed in next-intl@0.1.1.

Please let me know though about the question from above how other libraries handle missing keys with default values.

Thank you by the way for giving the library a shot and providing feedback! This is really helpful to better understand use cases of others.

[ilanbm]

thanks for the fix!

about missing key, I think they all do raise an exception on missing key, but I think most of them offer a default fallback value at the translate function/component itself.

I didn't check but I think i18next shows the key itself when it doesn't find it

Anyway I do think it should raise an exception on missing key, but should have a way to have a default value, and also a flag 'raise exception on missing keys"

[amannn]

Thanks again for your feedback! I did some research and I agree that we should be able to keep the app running in more instances, like when messages are missing.

I've wrote up a detailed plan on how I think errors could be handled: #8.

Would you like to have a look and let me know if this sounds reasonable from your perspective?

[ilanbm]

sure, checking

[amannn]

@eug-vs has shared his solution for merging messages and adding a prefix in #231.