onConsoleAPICalled panics if an argument in console.log is null

[nuarhu]

Brief summary

Logging a dynamic variable with console.log that can be null (or undefined) results in a go panic.

xk6-browser version

k6 v0.42.0

OS

macOS Ventura 13.1 (go1.19.4, darwin/arm64)

Chrome version

109.0.5414.119

Docker version and image (if applicable)

No response

Steps to reproduce the problem

The relevant code in TypeScript seems to be for example:

const someVar: null | boolean = null // dynamically set
console.log('some log information', someVar)

Expected behaviour

Just don't panic when there is null.

Actual behaviour

Panic (see stack trace above)

[inancgumus]

@nuarhu, thanks for reporting the issue; we'll take a look. In the meantime, could you share the whole TypeScript code?

[nuarhu]

@inancgumus

I'm not completely sure what you mean with "whole TypeScript code". The project itself would be a lot, and it's under NDA.
Here is the relevant React useEffect hook.

fullScreen can be null/undefined while this React component initializes, and this useEffect waits for it to change to either true or false.

  React.useEffect(() => {
    if (evtHandler && selCat && selColor) {
      console.log('>>>>>>>>>>> fullscreen change', fullScreen)
      const event = {
        // omitted
      }
      if (fullScreen) {
        evtHandler.fullscreenStart(event)
      } else if (visFullScreen === false) {
        evtHandler.fullscreenEnd(event)
      }
    }
  }, [evtHandler, selCat, selColor, fullScreen])

We have changed the code so that the console.log only runs whenever fullScreen is defined, and this panic does not occur anymore. This seems to prove that a console.log('something', null) (or undefined) leads to a panic in the go code.

[ankur22]

@nuarhu this issue looks very similar to #793 and #777. We've marked those as resolved since #859 fixed the issue. Once we release v0.45.0 of k6 you should be able to test it against your website and see whether that fix also works for your case.

[inancgumus]

Maybe related: #987.