JavaScript vm broken (bad Proxy implementation?)

[freehuntx]

Describe the bug

When defining properties on a object returned by the vm, they behave differently than in NodeJS.
This breaks for example the testing framework Jest. (As you can see here: #293)

Example code:

const { runInContext, createContext } = require('vm');

const context = createContext();
const vmGlobal = runInContext('this', context);

Object.defineProperties(vmGlobal, {
  works: {
    configurable: true,
    value: 'This will work'
  },
  worksNot: {
    configurable: false,
    value: 'This will not work (in webcontainer)'
  }
});

console.log(vmGlobal.works); // success
console.log(vmGlobal.worksNot); // error
Object.keys(vmGlobal); // error

Link to the blitz that caused the error

https://stackblitz.com/edit/node-7mnp6x

Steps to reproduce

1. Open the linked stackblitz
2. run node index in the console
3. See the error

Expected behavior

Console should print:

This will work
This will not work (in webcontainer)

Screenshots

Platform

Browser name  = Chrome 
Full version  = 92.0.4515.159
Major version = 92
navigator.appName = Netscape
navigator.userAgent = Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36
performance.memory = {
  "totalJSHeapSize": 96025376,
  "usedJSHeapSize": 90858908,
  "jsHeapSizeLimit": 4294705152
}
Hash = 8ffc536d8181e8b30c228dec423d18afae547c40

Additional context

I created this bug ticket as a result of this: #293

[freehuntx]

Maybe the issue lays somewhere else. Take this script for example:

const { runInContext, createContext } = require('vm');

console.log(runInContext('this', createContext()));
console.log(runInContext('global', createContext()));

In stackblitz this works, in native NodeJS not. Since global should not be defined. Also "this" seems to be different than in native NodeJS.

[d3lm]

Thanks for reporting this issue. It seems to be a bug.

[d3lm]

Good news, this has been fixed and it's now available. Here's an example. I have also tested jest@27 and it seems to work. Maybe give it another whirl and let us how it goes. Please create a new issue if there's still a problem.

[freehuntx]

You guys are awesome! It works, thanks!

[d3lm]

@freehuntx Just a quick update that vm.runInContext('global', vm.createContext()) won't behave the same as on local. I had to change this again because the way I fixed it does not work in all cases and typeof global was also throwing a reference error. Unfortunately, this is a limitation of WebContainer's vm module. The closest I can get is to return undefined if you try to evaluate global and the context doesn't define it. It's a bummer but sadly a hard limitation. But I'd say this is an edge case, and the rest still works as expected.