Question

When defining a JS object with a constructor function, is there any way to avoid having to use “this” with every single object property? It seems very ugly. E.g.

function Thingy(abc) {
  this.var1 = abc;
  this.var2 = this.var1 + " hello ";
  // etc
}

var myObj = new Thingy();

It seems that I should be able to use “var var2” and then leave out the “this” and just refer to “var2”, but am I missing something?

Answer 1

Well, I’m afraid that you’re running into how the language is designed.

But there is a sense in which you can use the plain var statements from the constructor. Any functions created in there have access to the closure that includes these properties:

function Thingy(abc) {
    var var1 = abc;
    this.func1 = function(str) {return var1 + ", hello";};
}

var thing1 = new Thingy("Dan");
thing1.func1();  // => "Dan, hello"

Note this is how you can encapsulate entirely private variables in an object, so it’s often a useful technique.