Show Runtime Values vs. defineProperty on globals

[oculus42]

Hello! This is very minor and is only an issue with Show Runtime Values - Experimental checked, but I thought it would be worth reporting, mostly in case others come across it.

The conditions I've encountered may not be everything, but are fairly specific:

• Show Runtime Values - Experimental is checked.
• Object.defineProperty modifies a global value (e.g. Array.prototype)
• defineProperty uses a getter, setter, or explicitly sets writable: false.
• Any valid syntax follows the defineProperty call, even if it would throw an error.

When using defineProperty on a global like Array.prototype I encounter TypeError: Cannot redefine property: and execution stops, but only if there is code following the defineProperty call:

// Code before executes as expected and displays output
a = 2;

Object.defineProperty(Array.prototype, 'not', {
  get() { return false; },
});

// TypeError: Cannot redefine property: not
//  happens and execution stops if any code is after define
//  with valid syntax, even if it would throw an error
b;

The error does not happen with a local variable:

const a = { is: true };
// No error when defineProperty is on a local variable
Object.defineProperty(a, 'not', {
  get() { return !this.is; },
});

a.is; // true
a.not; // false

And an image demonstrating the error for completeness:

I'm not sure if this is a worth further research as it works properly when you turn off Show Runtime Values.

Thank you so much for making this amazing tool. I love it and regularly recommend it to others.

[lukehaas]

@oculus42 this seems to be working ok now in the latest version of RunJS.