Add x-enum-varnames support

[goodoldneon]

Currently, json-schema-to-typescript uses a custom tsEnumNames extension for naming enum members. However, this extension is specific only to this library. Other major OpenAPI generators (1, 2) have adopted x-enum-varnames for the same purpose, so this PR brings json-schema-to-typescript in line with them.

This PR addresses feature request #200.

[bcherny]

Thanks for the contribution!

Can you also add a normalizer step to convert tsEnumNames -> x-enum-varnames, and throw if the latter is already defined and different from what we would have generated?

That will also let you simplify your changes to parser.ts a tiny bit.

[goodoldneon]

@bcherny Would I add the following rule:

rules.set('Convert tsEnumNames -> x-enum-varnames', schema => {
  if (schema.tsEnumNames) {
    schema['x-enum-varnames'] = schema.tsEnumNames
    delete schema.tsEnumNames
  }
})

And then be able to always reference ['x-enum-varnames'], even when the spec actually uses .tsEnumNames?

[bcherny]

Yup, exactly. Don't forget to validate when you do that too, to make sure the schema doesn't already have conflicting x-enum-varnames and tsEnumNames defined.

[goodoldneon]

Is there a way to log a deprecation warning so that consumers know tsEnumNames may eventually be removed?

[goodoldneon]

@bcherny are you OK with the way I'm handling the existence of both x-enum-varnames and tsEnumNames? I figured throwing an error would be fine

[bcherny]

Looking better -- almost there!

[bcherny]

Mind being a little more lenient, and only throwing if the two don't match? These should also have tests, if possible.

ie.

// ok
{
  tsEnumNames: ['a']
}

// ok
{
  x-enum-varnames: ['a']
}

// ok
{
  tsEnumNames: ['a'],
  x-enum-varnames: ['a']
}

// error
{
  tsEnumNames: ['a'],
  x-enum-varnames: []
}

// error
{
  tsEnumNames: [],
  x-enum-varnames: ['a']
}

// error
{
  tsEnumNames: ['a'],
  x-enum-varnames: ['b']
}

// error
{
  tsEnumNames: ['a'],
  x-enum-varnames: ['a', 'b']
}

[bcherny]

Normalized schemas shouldn't contain tsEnumNames, since you're normalizing it away.

[goodoldneon]

So I should delete DeprecatedNamedEnumJSONSchema and rename _NamedEnumJSONSchema to NamedEnumJSONSchema?

[bcherny]

Yeah just add x-enum-varnames: string[] and tsEnumNames: never to NormalizedJSONSchema. No need for new types if you can avoid it.

[bcherny]

Please make sure this is still covered by tests.

[goodoldneon]

Should I copy enumValidation.1.ts and enumValidation.2.ts, but sed "s/tsEnumNames/x-enum-varnames/" in the new test files?

[bcherny]

Sounds ok to me, or merge into a single test file that covers all the cases (x-, ts-, x- and ts-, etc.).

[bcherny]

Please make sure this is still covered by tests.

[galah92]

Hi, is there any chance it'll get merged soon?

[goodoldneon]

@galah92 I have a couple open questions for @bcherny. I can pick this back up when he answers

[bcherny]

Yeah just add x-enum-varnames: string[] and tsEnumNames: never to NormalizedJSONSchema. No need for new types if you can avoid it.

[bcherny]

Sounds ok to me, or merge into a single test file that covers all the cases (x-, ts-, x- and ts-, etc.).

[bcherny]

@galah92 I have a couple open questions for @bcherny. I can pick this back up when he answers

Sorry I missed this! The status was Changes Requested, so I missed your comments.

[goodoldneon]

No worries, @bcherny!

I started taking a look at this PR again and I'm having a hard time understanding my changes 😅. I think it'd take some effort to ramp myself back up, unfortunately. If this is something you could bang out quickly, then that's probably best. But if that's not the case then I can try to work on this again

[bcherny]

Closing out stale PRs. If you'd like to revisit this, feel free to re-open.