Injected script: Avoid depending on globals

[inancgumus]

What

The injected script should not depend on global JavaScript objects, such as Set and Map.

Why

Websites under test can overwrite these objects, leading to unexpected behavior.

Example

One website can overwrite Set with a simple function like this:

function Set() {
    ...
}

The injected script would then use the function above while it was expecting a native Set object here, leading to unexpected issues, like throwing exceptions when it shouldn't have.