es78-this-scope.js

/**
 * JS scoping, and this property resolutions rules in ES7/ES8.
 *
 * Quiz: x is gone, and x is everywhere!
 *
 * Help find Xs! What's the output?
 */ 

let x = 1;

({
  x: 2,
  run() {
    (new class X {
      x = 3;
      static x = 4;

      getX = () => {
        return this.x;
      };

      static getX = () => {
        return this.x;
      };

      exec() {
        console.log(X.getX() + this.getX());
      }
    }).exec();
  }
}).run(); // ?