Self-references in object literals/initializers

Question

Is there any way to make something like the following work in JavaScript?

var foo = {
    a: 5,
    b: 6,
    c: this.a this.b // Doesn't work
};

In its current form, this code obviously throws a reference error because this does not reference foo. ButyesIs there any way to make the value in an object literal property dependent on other previously declared properties?

Answer 1

You can do this:

var foo = {
   a: 5,
   b: 6,
   init: function() {
       this.c = this.a + this.b;
       return this;
   }
}.init();

This will be some kind of one-time initialization of the object.

Note that you are actually assigning the return value of init() to foo, so you must return that value .

Answer 2

Well, the only thing I can tell you is

var foo = {
  a: 5,
  b: 6,
  get c() {
    return this.a + this.b;
  }
}

console.log(foo.c) // 11