Deprecate @nrwl/cypress/plugins/preprocessor

In the generated index.js pluginFile of cypress the nx helper is there to preprocess TS Files.

  // Preprocess Typescript file using Nx helper
  on('file:preprocessor', preprocessTypescript(config));

Since Cypress 4.4.0 (4/13/2020), it supports typescript out of the box

Added support for TypeScript without needing your own transpilation through preprocessors.

https://docs.cypress.io/guides/tooling/typescript-support.html#History

If the nx preprocessor is more than that, then please clarify in the comment why it’s needed.

In a fresh project I tried to run e2e with the plugin removed and it ran fine. But then again, that was an empty workspace with a blank angular app.

[george43g]

The latest Cypress has TS support built-in. I’m not sure what this means about the preprocessor hook personally - check out this thread for more info: https://github.com/cypress-io/cypress/pull/5906

But I wanted to point out a couple of important points: In the default schematic, the generated cypress.json file should have a few changes made: the pluginsFile needs to point directly to plugins/index.ts with the file extension. The default from when I set it up earlier in the year was plugins/index. This caused a crash.

This means that the default pluginsFile also needs to be updated to TS. I actually suspect that their preprocessor does a little more than transpile - it also had some tsconfig paths module in its source code and I suspect this is set up this way in order to be able to resolve the library paths as configured in the paths property in tsconfig. This is generally a pain point with tsc and is why they use webpack to bundle apps in NX. In order to be able to resolve these library paths while running ts-node, I think you might need extra functionality in the preprocessor, hence why they built their own rather than using the one that was available previously to the Cypress community.

It would be really helpful to be able to not only write plugins in TS, but also be able to require TS libraries from within the plugins file!

I also think that typescript: 'project' is a setting that should be set as well (please double-check this as I only had a cursory glance) but I’m not sure where from. I just know it’s checked in the Cypress source code.

[FrozenPandaz]

I agree, let’s start investigating by opening a PR against https://github.com/nrwl/nx-examples with the preprocessor removed to see if everything works as expected there.