V8 Natives Syntax

[PandaWorker]

I need to use native syntax for debugging, but amaro (swc) thinks it's invalid syntax.

//@ts-expect-error
%DebugPrint(null);

//@ts-expect-error
%DebugPrint(null);
^

SyntaxError [ERR_INVALID_TYPESCRIPT_SYNTAX]: Expression expected

[acutmore]

Maybe you could use eval("%DebugPrint(null)")?

[marco-ippolito]

I dont know if swc supports this syntax @kdy1

[kdy1]

No. It does not support such syntax atm. Does SWC should?

[marco-ippolito]

No. It does not support such syntax atm. Does SWC should?

Maybe behind a flag? So it does not throw when encountering this syntax.
So when user pass --allow-native-syntax we enable it

[acutmore]

This syntax is specific to v8. It is neither valid TypeScript or JavaScript.

It is not parsed by tsc either: https://www.typescriptlang.org/play/?#code/PTAEAEBcGcFoFMAeAHeBjSCBOWD2WAoAUgBF4AjAVwHMAFLASwDtIAKJygG04EoBuAkA(the %DebugPrint() becomes % DebugPrint()). It's just that tsc will still attempt to output JS even if there is a syntax error. In this particular case it turns out that v8 is OK will the re-printing of the input.

In other invalid syntax cases TypeScript will insert a ; as the parser recovers:

https://www.typescriptlang.org/play/?#code/PTAEAEBcGcFoFMAeAHeBjSCBOWD2WAoAO10lABJQA3AQwBsBLAEwG4g (not $ valid becomes not; $; valid;).