haXe 2

Time for action – Writing an extern

Imagine that we are writing a User class in JavaScript:

function User()
{
   var name;
   var age;
}
User.prototype.outputInfo = function()
{
   var el = document.createElement("div");
   el.innerHTML = this.name+"("+ this.age+")";
   document.body.appendChild(el);
}

Now, if we want to use this class from our haXe application, then we have to write the corresponding extern class as follows:

extern class User
{
   public var name:String;
   public var age:Int;
   public function outputInfo():Void;
   public function new():Void;
}

There are several things that you should note:

• You have to prefix your class declaration with the extern keyword
• We do not write any code inside function declaration
• Constructors should be declared returning Void