Prototypical Javascript design approach [closed]

Question

Is there anything functionally different about this prototypical design pattern:

var Greeter = function(message) {
    this.greeting = message;
    return this;
}

Greeter.prototype.greet = function () {
    return "Hellos, " + this.greeting;
}

As opposed to:

var Greeter = (function () {
    function Greeter(message) {
        this.greeting = message;
    }
    Greeter.prototype.greet = function () {
        return "Hellos, " + this.greeting;
    };
    return Greeter;
}());

The bottom approach seems to be cleaner and so I opt into using that more often, but I have seen many people use the top approach.

Answer 1

You will note that the core logic in both examples is pretty much the same. So really the only difference here is whether you allow the function (class) definition to be callable from global scope.

In the second example, wrapping the logic in an IIFE has the effect of hiding the function definition from global scope, in essence providing singleton behavior.

Which you might use could depend on the needs of your application.