Follow-on after #19675.
The type for `lint` function that NAPI-RS produces is incorrect. `Option::None` on Rust side is translated to `null`, never `undefined`. Check this with a debug assertion, instead of handling `undefined` at runtime (which is pointless, because it never is `undefined`).
Pure refactor. Replace `typeAssertIs` with debug assertions. Both perform the same type assertion, but difference is that the debug assertion actually checks that the type is correct at runtime in debug build.
Add a `debugAssert` function, which works the same as `debug_assert!` in Rust. We can use this to add more assertions to rest of code.
Same as `debugAssertIsNonNull` and `typeAssertIs`, this function will be removed entirely in release build - it only performs the check in debug build (which is used in the tests).
Rename assertion functions to clarify that they're not "real" assertions which we can rely on for validating input, and are only for compile-time testing or debug assertions.
`typeAssertIs` is not a great name, but I couldn't come up with anything better. `debugAssertIs` would be not be accurate, as it'd imply that in debug builds in performs an actual assertion, which it doesn't.
In any case, we should replace `typeAssertIs` with specialized assertion functions which do actually perform runtime assertions in debug builds (e.g. `typeAssertIs<Fix>()` -> `debugAssertIsFix()`).
Pure refactor. Split up `plugins/utils.ts` into 3 files in `utils` directory.
Most importantly, assertion functions are by themselves in an `asserts.ts` file. This paves the way for the next PR (#15946).
overlookmotel