# reject-globalThis-modification

Reject any modification to `globalThis` inside the system modules.

`globalThis` is the shared global inside the system modules, and modification
on it is visible from all modules, and it shouldn't be done unless it's really
necessary.

## Examples of incorrect code for this rule

```js
globalThis.foo = 10;
Object.defineProperty(globalThis, "bar", { value: 20});
ChromeUtils.defineESModuleGetters(globalThis, {
  AppConstants: "resource://gre/modules/AppConstants.sys.mjs",
});
```