Clarifying this in JavaScript example 2

this_js_ex2.js

const foo = {
  bar: 'baz',
  getBar: function() {      
    console.log(this.bar);  
  },
};              

let qux = foo.getBar;     

qux.call(foo);             // logs 'baz'
qux();                     // logs undefined

qux.apply(foo);            // logs 'baz'
qux();                     // logs undefined