JavaScript Function Facts

[u/hsnice]

[u/[deleted]]

function declarations aren't the only thing that is hoisted, variable declarations with var are also hoisted.

e.g. the following does not work:

console.log('hello', future());
const future = function() { 
   return ' world'; 
}

[u/[deleted] → u/[deleted]]

Does using var have a higher cost than using let? Does hoisting have a cost?

[u/[deleted] → u/[deleted]]

the only difference is, that you can't redeclare a let/const variable and that var variable are hoisted to the top. There is no cost.

[u/[deleted] → u/[deleted]]

You can redeclare let. I thought the only difference was scoping.

[u/[deleted] → u/[deleted]]

Reassign, yes, but not redeclare.

 let assignment = 3;
 assignment = true;

 let declaring = function() {}
 let declaring = false; // here will be a redeclaration error

[u/[deleted] → u/[deleted]]

We’ll that’s not really redeclaration is it? You’re assigning 2 variables with the same name?

[u/[deleted] → u/[deleted]]

I’ll be honest I thought reassigning was redeclaration.