Errors that you would expect to get by running the typescript compiler are not being reported by the transformer

Basically, if you write something like this in typescript:

    switch (x) {
      case 1:
      console.log('y');
      case 2:
      console.log(x);
    }

And put: "noFallthroughCasesInSwitch": true,

in your tsconfig.json, then if you compile w/ typescript (e.g. tsc) you’ll get an error. Thats good!

BUT, with the transformer, the typescript is transpiled successfully, and you don’t get an error.

There seems to be a whole slew of little nice errors you get normally with the typescript compiler, that the transformer isn’t reporting.

I believe its probably because the transpileModule function you are using does not do the full analysis that the normal complication pass does.

This seems relevant: https://github.com/Microsoft/TypeScript/issues/4864

Do you have any idea how we could fix this?

Thanks! Aaron

[ds300]

That is the desired behaviour. i.e. the transformer should only report syntax errors which prevent emitting code. All other errors should be displayed/reported by external tooling like code highlighting and a precommit hook that runs tsc --noEmit.

Otherwise you couldn’t run type-unsafe code a dev time. Which might sound like an insane desire to some people, “why would you ever want to run unsafe code”, but is actually a very productive feature because it lets you experiment and make incremental changes with less overhead.

[aarondail]

Thanks for your response. I have been thinking about this for a few days… I admit it does feel a little foreign to me, but what you are saying is reasonable and I think I am coming over to your point of view. 😃

We are also going to be running tslint anyways, and if I think of these sorts of errors more like linting errors, then it feels very natural to not prevent emitting code on those errors.

So, yeah, in summary, I think I agree with you, and thank you for working on this project 😃