Can you explain this weird function declaration behavior?

Question

Can you explain this?

var guessWhat = function(){ console.log('Print this!!!'); };
function guessWhat(){ console.log('Print that???'); }
guessWhat();

// output: Print this!!!

Both are declared on the global scope. Why is the the second line not overriding the first? Is the second function lost in limbo?

Maybe the two fo them exist but stored in different places in memory, and variable are resolved before functions ? But this may not be true on all browsers — Walfrat, Mar 02 '16 at 12:45
I'm thinking something about preference in `var = guessWhat`, is a local variable. Maybe takes precedence over the global function at line 2? — Frederik Spang, Mar 02 '16 at 12:48
http://stackoverflow.com/questions/336859/var-functionname-function-vs-function-functionname — jolmos, Mar 02 '16 at 12:48

score 4 · Accepted Answer · edited May 23 '17 at 12:33

4

function guessWhat(){ console.log('Print that???'); } // declaration

This is a function declaration, it is defined before any code is executed.

var guessWhat = function(){ console.log('Print this!!!'); }; // literal

This is a function literal, it is defined at run-time.

so, the function definition gets loaded first (before any code), and the function literal afterwards, which overrides the first definition, hence this behaviour.

Read more here.

edited May 23 '17 at 12:33

Community

1
1

answered Mar 02 '16 at 12:48

Akshay Arora

1,953
1
14
30

1

__loaded__ can not be the word... – Rayon Mar 02 '16 at 12:49
@RayonDabre, Yes. Thanks. :) – Akshay Arora Mar 02 '16 at 12:50
1

@orr-siloni an answer to the same question elsewhere on stackoverflow that backs this one up http://stackoverflow.com/a/35704772/2646455 – chris.nesbit1 Mar 02 '16 at 12:51

Can you explain this weird function declaration behavior?

1 Answers1