Typescript global variables becoming undefined after function call

Question

In my code, I have two global variables defined as

constructor() {
        this.map = new Map();
        this.player = new Player([], \"\");
    }

Answer 1

Your this is most likely referring to another object depending on how handleInput is being called. In your contructor(), either bind handleInput to this or change your handleInput to use arrow function:

constructor() {
  this.handleInput = this.handleInput.bind(this);
}

Or:

handleInput = (cmd:Command, arg:string):boolean => {}