Example for this

this-example-1.js

this.coffee = false;

function Employee(coffee) {
    this.coffee = coffee;

    const enterOffice = function() {
      if(this.coffee) {
        console.log('good morning!');
      } else {
        console.log('this sucks');
      }
    }

    return {
      enterOffice: enterOffice
    }
}

const heather = new Employee(true);

heather.enterOffice(); // this sucks