— It works for me. displayTime is showing a different value every second.
— Yes but does it update newGame.startTime property
— That's what I need to achieve
— Yes it does. But, when your calling the play method it evaluates that expression and passes it like a value. That’s why it never updates that value. But if instead of func you put in the console.log a this.startTime you should see the new value.
If I understood well maybe you want something like
newGame.play(() => newGame.startTime)
and inside of the console you execute the argument func.