Functions that return a function

Question

Can anyone help me with the functions that returns functions concept? I have these two code snippets:

function a() {

      

        alert('A!');

    

        function b(){

            alert('B!'); 

        }

    

        return b();

    }

    

    var s = a();

    alert('break');

    s();

Output:

A!

B!

break

Snippet 2:

function a() {

  

    alert('A!');

    function b(){

        alert('B!'); 

    }

    return b;

}

var s = a();

alert('break');

s();

Output:

A!

break

B!

Can anyone help me what is the difference between returning b and b()?

Answer 1

Basically, return the fucntion without bracs means it is returning the reference to the fucntion, whereas the function with () will going to execute the function and returns the value which is returned by the function.

// Execute function b() and return its value

return b();

// If b() has no return value, this is equivalent to calling b(), followed by

// return undefined;

I hope this will help.

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