docs: add note about line discrepancies and returning source maps in code transformers #12566
Conversation
…code transformers
docs/CodeTransformation.md
Outdated
| @@ -128,6 +128,12 @@ As can be seen, only `process` or `processAsync` is mandatory to implement, alth | |||
|
|
|||
| Note that [ECMAScript module](ECMAScriptModules.md) support is indicated by the passed in `supports*` options. Specifically `supportsDynamicImport: true` means the transformer can return `import()` expressions, which is supported by both ESM and CJS. If `supportsStaticESM: true` it means top level `import` statements are supported and the code will be interpreted as ESM and not CJS. See [Node's docs](https://nodejs.org/api/esm.html#esm_differences_between_es_modules_and_commonjs) for details on the differences. | |||
|
|
|||
| :::info | |||
There was a problem hiding this comment.
Can we flip this around? maybe as a tip and something like "make sure your transformation returns a source map so it's possible to map back from the transformed code to the source code in code coverage and error information" or some such? Inline sourcemaps also work, doesn't have to be an explicit return value (although separate is preferred for performance reasons)
There was a problem hiding this comment.
Sure thing @SimenB. How does this sound?
Make sure
TransformedSourcecontains a source map, so it is possible to report line information accurately in code coverage and test errors. Inline source maps also work but are slower.
I actually didn't know about inline source maps so when I was writing my own code transformer I had to separate our maps because I didn't know that option existed so having this kind of tip should be helpful.
|
This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs. |
Summary
Added a new note in the Code Transformation page about line discrepancies when source maps are not returned by the
processorprocessAsyncfunctions. Was just generally confusing why my errors were pointing to a different place.Test plan
Only docs are changed -> proofread
Related Issue:
#10305 ?