Setting javascript prototype function within object class declaration

Question

Normally, I\'ve seen prototype functions declared outside the class definition, like this:

function Container(param) {
    this.member = param;
}
Container.p         


        

Answer 1

To get the behavior you want you need to assign each individual object separate stamp() functions with unique closures:

Container = function(param) {
    this.member = param;
    var privateVar = param;
    this.stamp = function(string) {
        return privateVar + this.member + string;
    }
}

When you create a single function on the prototype each object uses the same function, with the function closing over the very first Container's privateVar.

By assigning this.stamp = ... each time the constructor is called each object will get its own stamp() function. This is necessary since each stamp() needs to close over a different privateVar variable.