console.log printing 'undefined' when calling this on a variable

Question

I'm new to JavaScript, I can't find a clear answer to what's going on here:

 function bike() { console.log(this.name); } var name = "John"; var obj1 = { name: "Sam", bike: bike }; var obj2 = { name: "Paul", bike: bike }; bike(); // undefined obj1.bike(); // Sam obj2.bike(); // Paul

I don't understand why it's printing 'undefined' on the terminal instead of 'John'

Answer 1

Nothing wrong with this Behaviour,

function bike() {
  console.log(this.name);
}

var name = "John";
var obj1 = {
  name: "Sam",
  bike: bike
};
var obj2 = {
  name: "Paul",
  bike: bike
};

bike(); // undefined here it refers to (**this**).name
        //if you run the same in browser console 
        // you will get jhon
        // but in node there is no window object
        // that's y you are getting undefined in node terminal

obj1.bike(); // Sam
obj2.bike(); // Paul

Plz refer the link ASDFGerte suggested for more

Answer 2

it's Simple you just write

window.name

window.variableName it is used to print global variable