JavaScript evaluated by the Notebook renderer is evaluated in the global scope

[DonJayamanne]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version: All
• OS Version: All

Steps to Reproduce:

1. Create a jupyter notebook with Pyhton
   2.Run the following cell twice and have a look at the console output in the renderrers

%%javascript
const helloWorld = 2134;

Basically the error indicates the fact that the const helloWorld has already been declared once before.

The problem is we're evaluating the JS in the same global scope.
Jupyter doesn't seem to be evaluating them in the global scope.

Here's the problematic code

function renderJavascript(outputInfo, container) {
  const str = outputInfo.text();
  const scriptVal = `<script type="application/javascript">${str}</script>`;
  const element = document.createElement("div");
  const trustedHtml = ttPolicy?.createHTML(scriptVal) ?? scriptVal;
  element.innerHTML = trustedHtml;
  container.appendChild(element);
  domEval(element);
}

Not sure if others (extensions) rely on this to run in the global scope, hence I'd suggest adding a metadata for JS mimetypes to ensure the code is evaluated in a private scope, e.g. isolated.
Jupyter has similar concepts when rendering HTML, https://ipython.org/ipython-doc/3/notebook/nbformat.html#output-metadata

Perhaps we could do the same thing, to ensure the existing functionality stays as is (for the benefit of existing extension authors).

[DonJayamanne]

@mjbvz I'd like to work on addressing this issue, we can sync up next week or some time tomorrow.

[vscodenpa]

This bug has been fixed in the latest release of VS Code Insiders!

@DonJayamanne, you can help us out by commenting /verified if things are now working as expected.

If things still don't seem right, please ensure you're on version 2c80125 of Insiders (today's or later - you can use Help: About in the command palette to check), and leave a comment letting us know what isn't working as expected.

Happy Coding!