this.dropped = false?

Here's the deal, you have 3 options.

Option 1 - you pass the 'dropped' property as a parameter and when you create an instance of that object you can set the value to true or false.

Option 2 - you don't pass the 'dropped' attribute as a parameter, in the constructor you set it to true or false and whenever you create an instance of that object it will always have the same value.

Option 3 - you pass the 'dropped' property as a parameter and inside the parenthesis you set it to a value ('dropped = true' or 'dropped = false'). When you create a new instance of that object you can use that argument or not. If you use it it will have the value you passed in as a parameter, but if you don't it will use the 'default value' (the value you put in the constructor method).

Hope it helps!

The constructor is creating a new variable named "this.dropped". There is not any identifier named just "dropped" that could be used as the source of an assignment.

Also, assignment order is important. Even if an identifier named "dropped" were accessible, using it to assign "this.dropped" first would give it the value it had at that moment, which might not be "false".

I'm not sure I understand. Is there a difference between:

class Token {
    constructor(index, owner){
        this.owner = owner;
        this.id = `token-${index}-${owner.id}`;
        this.dropped = false;
    }
}

and

class Token {
    constructor(index, owner, dropped = false){
        this.owner = owner;
        this.id = `token-${index}-${owner.id}`;
        this.dropped = dropped;
    }
}

?

This was how the "active" property was defined in the Player constructor.