Improve error when translation is missing for a given key

[viniciusoyama]

Proposed changes

Today, if I try to fetch a message passing the wrong key I get an error from the intl-messageformat lib:

> const Antl = use('Antl')
> Antl.formatMessage('messages.greeting')
TypeError: A message must be provided as a String or AST.
    at new MessageFormat (/Users/viny/Projects/fleury-checkup-executivo/node_modules/intl-messageformat/lib/core.js:21:15)
    at /Users/viny/Projects/fleury-checkup-executivo/node_modules/intl-format-cache/lib/memoizer.js:24:22
    at Formatter.formatMessage (/Users/viny/Projects/fleury-checkup-executivo/node_modules/@adonisjs/antl/src/Formatter/index.js:177:12)
    at Antl.formatMessage (/Users/viny/Projects/fleury-checkup-executivo/node_modules/@adonisjs/antl/src/Antl/index.js:113:28)
    at repl:1:6
    at Script.runInContext (vm.js:107:20)
    at REPLServer.defaultEval (repl.js:331:29)
    at bound (domain.js:396:14)
    at REPLServer.runBound (domain.js:409:12)

I've changed the code so we can have a more descriptive error containing the current locale and key:

InvalidArgumentException: E_INVALID_PARAMETER: Missing pt translation for key 'messages.greeting'

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have read the CONTRIBUTING doc
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works.
• I have added necessary documentation (if appropriate)

Further comments

Maybe we should create some integration tests. This is a case that the suite was not covering...

[coveralls]

Coverage increased (+0.08%) to 96.0% when pulling e37d19e on viniciusoyama:develop into e54c93f on adonisjs:develop.

[thetutlage]

You are changing the functionality of the get method, which introduces an unnecessary breaking change for applications expecting null.

Instead, you should change formatMessage to throw a more helpful error

[viniciusoyama]

Hi. I can do that but I thought about implementing like you said before and I think that the get() method it's more private than public.

I couldn't find any documentation about that on the AdonisJS documentation so no one should be using it.

Even if there is someone using the get method, expecting it to return null I see as an anti-pattern and it's very likely to end in a case where there is some kind of typo and the developer will never know that there is an error because the method is returning null.

Of course that I can understand your point so I will do what you think it's better 👍

[viniciusoyama]

Done! I've also added a test for the formatMessage method.

Thanks for the quick feedback. 👍

[thetutlage]

Looks great :)