No information on error message in Javascript Kernel in Firefox

[dvd101x]

Description

Hi, while working on jupyter lite in firefox with the Javascript Kernel and making a mistake in a cell like:

2 +

I get no information about what was the error.

execute@https://jupyterlite.github.io/demo/extensi

In Chrome I'm getting the expected syntax error

SyntaxError: Unexpected end of input
    at eval (<anonymous>)
    at Object.execute (https://jupyterlite.github.io/demo/extensions

Another example in Firefox

2 + undefinedVariable

@https://jupyterlite.github.io/demo/extensions/@jupyterlite/javascript-kernel-extension/static/584.7e49152bd31ca0f8291b.js?v=7e49152bd31ca0f8291b line 2 > eval:1:5

But in chrome

ReferenceError: undefinedVariable is not defined
    at eval (eval at execute...

A workaround as long it's not a syntax error is to use try catch

try {
    2 + undefinedVariable
    }
catch (err) {err.toString()}

'ReferenceError: undefinedVariable is not defined'

Reproduce

1. Open jupyterlite in firefox, open a javascript kernel and run a cell with 1+a
2. See that no information about the error is shown.

Expected behavior

Return information of the error as it does in chrome or edge

ReferenceError: a is not defined

Context

• JupyterLite version: Version 0.5.0
• Operating System and version: Windows 11 Enterprise 23H2
• Browser and version: Firefox 136.0.3

Browser Output

No console error is shown

[jtpio]

Thanks @dvd101x for the report.

This appears to be an issue with the JavaScript kernel, so moving to the related repo.