This is just an arbitrary message rather than something indicating a specific diagnostic to suppress, right?

Could be useful to have a way to give a specific one to hide (say, something matching @ts-suppress\(T(\d+)\)), in a similar way how linter comments have a way to give a specific rule to disable; but that could be a future enhancement.

That is what i had in mind with test. but the error code seemed fairly useless. like you need to go somewhere to know what TS 20124 means. Linter rules usually have descriptive names.

I think this is something we can target for in the future.

Is it supposed to work in .ts files too?

nope. js only and only for semantic errors.

I actually wanted this functionality in .ts a few days ago -- embedding a chunk of stable JS code in TS code.

Sometimes you need to embed code rather than have it as an external module, for encapsulation. Such as, I was writing a plugin that needed to use compression, and I've embedded LZW algo in my ts plugin.

Of course LZW algo in JS needed a bunch of : any kicks to pass TSC checks. Would be great to be able to exclude chunks of code in TS from checks in such cases.

Do you need to add an entry in src/harness/tsconfig.json as well?

added.