feat: generate type namespaces for enums as literals

[samualtnorman]

this pull request adds code for generating a namespace of type declarations for enums as literals that let you use them like regular enums:
old:

let foo: typeof Foo.Bar

new:

let foo: Foo.Bar

this means a library that was previously using ts-proto without the enumsAsLiterals=true can add it with less breakages.

---

Foo.proto

enum Foo {
	Bar = 0;
	Baz = 1;
	Qux = 2;
}

old generated Foo.ts

export const Foo = { Bar: 0, Baz: 1, Qux: 2, UNRECOGNIZED: -1 } as const;

export type Foo = typeof Foo[keyof typeof Foo];

new generated Foo.ts

export const Foo = { Bar: 0, Baz: 1, Qux: 2, UNRECOGNIZED: -1 } as const;

export type Foo = typeof Foo[keyof typeof Foo];

export namespace Foo {
  export type Bar = typeof Foo.Bar;
  export type Baz = typeof Foo.Baz;
  export type Qux = typeof Foo.Qux;
  export type UNRECOGNIZED = typeof Foo.UNRECOGNIZED;
}

---

I've not looked into adding any tests or anything for this change, but if this feature is something you're interested in, I wouldn't mind adding tests (and making any other changes you request)

[stephenh]

Hi @samualtnorman . Thanks for the PR!

What you're trying to do makes sense, i.e. emulate the previous Foo.Bar syntax...I don't love using the namespace keyword, because awhile ago it wasn't supported in...some bundler...

But this is just for the type namespace, so I think it makes sense.

If you could find an integration-test/* directly that is using parameter.txt with enumsAsLiterals, and just maybe update an existing test/file in their to show your output is getting generated as you like, and then also be a regression test, that'd be great.

Thanks!

[samualtnorman]

what would the regression test be testing for?

[stephenh]

I was thinking just something in a test file that did someFunction(value: Foo.Bar) to show the Foo.Bar syntax working, but I think the checked-in generated output should be a good enough regression test. Thanks!

[stephenh]

🎉 This PR is included in version 1.163.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release
• v1.163.0

Your semantic-release bot 📦🚀

[samualtnorman]

thank you for accepting my change!