Question

Is it better to declare fields of a class in this way:

function MyClass() {
   this.aMethod = function() {
     // code
   }
}

Or this way:

function MyClass() {
}

MyClass.prototype.aMethod = function() {
  // code
}

Any why?

Thanks in advance.

Answer 1

The prototypal method, because it’s more efficient as it adds the function to the prototype meaning any objects created with the constructor automatically get that method, while the former/first way those methods have to be created for each and every little object you make individually.

Though really it depends on what you’re doing with the method. If you don’t need it to be a public method then you may opt with this.method or a function statement.