Understanding console.log(console.log(object))

Question

I am new to programming and js and I am trying to learn crux of javascript.

var obj1 = {
    name: 'rawn',
    fn: function() {
        console.log(this);
    }
};
console.log(obj1.fn());

When I output this I get the object(as expected) - {name: "rawn", fn: ƒ} and on another line I get - undefined . So my question is why and how do I get undefined ?

My understanding is that, we are writing this line - console.log(obj1.fn()); as , console.log(console.log(this)) , so how does javascript engine gives the result as undefined (what was put as undefined in the execution context)?

Answer 1

console.log(obj1.fn()) and console.log(console.log(this)) are not equivalent at all, but they actually have the same result for the same reason: the inner function does not return anything . The return value of these functions is undefined . Which is what the outer console.log logs.

Answer 2

This is because of two reasons. First, in console.log(this); the context of this inside the fn function is the object itself. Hence it prints the guts of obj1 .

Secondly, in console.log(obj1.fn()); , you are actually calling the method which returns nothing. Instead if you say console.log(obj1.fn); it will return:

ƒ () { console.log(this); }

Hope this helps.