transformer: legacy decorators

[Boshen]

legacy (typescript --experimentalDecorators)

esbuild: --loader=ts --tsconfig-raw='{"compilerOptions":{"experimentalDecorators":true}}'
tsc: https://www.typescriptlang.org/docs/handbook/decorators.html

[Boshen]

Will reopen when planned.

[Boshen]

experimental decorators and useDefineForClassFields: false is not support by oxc

From rolldown-vite integration.

[OskarLebuda]

@Boshen do we have any ETA?

[yyx990803]

For reference: https://github.com/evanw/decorator-tests

[OskarLebuda]

@Boshen @Dunqing do you have guys any kind of ETA?

[Boshen]

@Boshen @Dunqing do you have guys any kind of ETA?

What are you using oxc for that requires decorators, and which version of decorators do you need?

[OskarLebuda]

What are you using oxc for that requires decorators, and which version of decorators do you need?

These are TypeScripts decorators (--experimentalDecorators)

[OskarLebuda]

@Boshen do you have any updates for this issue? 😞

[Boshen]

The team has agreed to implement typescript --experimentalDecorators first, which is simpler and what most people use today. Research this week, implementation will probably start next weerk.

[Boshen]

Legacy decorator has been implemented and is being integrated into Rolldown.

A decorator?: DecoratorOptions option has been added to the oxc-transform package.

Stage 3 ecma decorators is tracked in

• transformer: ecma decorators #9170

[alfaproject]

This is good progress and much appreciated but without emitDecoratorMetadata it's pretty much useless for anyone using TypeScript legacy/experimental decorators because the biggest use case by far is the existing DI libraries out there which all need TS decorator metadata support. Unfortunately, the ECMAScript decorators do not have enough functionality to have decorator based DI containers yet.

There are exceptions like Angular which don't need emitDecoratorMetadata and have their own compiler for DI, and that's why esbuild actually added support for experimentalDecorators but I don't see them using OXC ever. The more likely scenario will probably be Next.js people wanting support for this but like I said, it won't be enough for them either for the exact same reason I mentioned above.