English to Igbo Translation Endpoint

[ebubae]

Describe your changes

Add English to Igbo Translation to the /translate endpoint.

Motivation and Context

We've recently added Igbo to English translation in #812. This PR updates the code to support English to Igbo translation as well.

[ijemmao]

Looking really good! Just a few comments about strings vs. maps

[ijemmao]

Instead of casting these strings together to create a key to determine the payload shape, I think the sourceLanguageCode could map to the desired payload shape. Something like

const PayloadKeyMap = {
  [LanguageEnum.Igbo]: 'igbo',
  [LanguageEnum.English]: 'english'
}

That way, we could take the value of indexing into that map to determine the final payload shape:

const payload = { [PayloadKeyMap[requestBody.sourceLanguageCode]: textToTranslate }

If requestBody.sourceLanguageCode === 'ibo' then we would get a final payload of { igbo: textToTranslate } (if my logic is correct 😅 )

I think there's an even cleaner way of us handling this, but I think relying on maps rather than strings to determine payload shapes is a more stable way to go

[ebubae]

Switched to something like this. Thanks for the suggestion!

[ijemmao]

I think we would want to update this map to rely on nested maps for better indexing:

const SUPPORTED_TRANSLATIONS = {
  [LanguageEnum.IGBO]: {
    [LanguageEnum.ENGLISH]: {
      maxInputLength: 120,
      translationAPI: IGBO_TO_ENGLISH_API,
    }
  },
  [LanguageEnum.ENGLISH]: {
    [LanguageEnum.IGBO]: {
      maxInputLength: 120,
      translationAPI: ENGLISH_TO_IGBO_API,
    }
  }
}

So then when we use SUPPORT_TRANSLATIONS we can index using our LanguageEnum values:

const translation = SUPPORTED_TRANSLATIONS[requestBody.sourceLanguageCode][requestBody.destinationLanguageCode] // === { maxInputLength: 120, translationAPI: IGBO_TO_ENGLISH_API }

[ijemmao]

I'm also interested to hear why we would want to move this to RemoteConfig! I think it's fine having this object here, but I might be missing something

[ebubae]

I ended up getting something to work that typescript could actually be happy with by indexing all the languages on the first level of the object. Inner languages don't need to map out each one as not to be overly exhaustive.