Question

Does defining functions inside a loop affect performance?

Like

var doSomething = function(element){
      $(element).whatever();
    };

return this.each(function(){
  doSomething(this);
})

vs

return this.each(function(){

  var element = this,
      doSomething = function(){
        element.whatever();
      };


  doSomething(); 
  ...
})

In 2nd version the function gets defined like 324532453245 times, depending on how many elements are being iterated, right?

Answer 1

Technically, you’re defining a defining the functions 80 bajillion times or so in both versions. For high volumes of iteration, you should get some performance benefit from defining it like this.

var doSomething = function(index, element){
      $(element).whatever();
    };

return this.each(doSomething);