Javascript Object Literal referring to another property in itself from another property - Stack Overflow

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I have a object literal:

var obj = {
    a : document.getElementById("ex1"),
    b : obj.a.document.getElementsByTagName("div")
};

I am having trouble with the b property, for some reason it is not letting that happen. Is this possible?

I have a object literal:

var obj = {
    a : document.getElementById("ex1"),
    b : obj.a.document.getElementsByTagName("div")
};

I am having trouble with the b property, for some reason it is not letting that happen. Is this possible?

• javascript
• object

Share Improve this question Follow asked Feb 16, 2012 at 19:23 bryan sammonbryan sammon 7,4411616 gold badges4040 silver badges5151 bronze badges 1

• 1 possible duplicate of Self-references in object literal declarations – zzzzBov Commented Jun 18, 2013 at 20:29

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3 Answers 3

Sorted by: Reset to default 6

The modern way to do this is with getter methods:

let obj = {
  firstName: "A’dab",
  lastName: "Farooqi"
  get fullName() {
    return this.firstName+" "+this.lastName;
  },
}

So now you can just write obj.fullName - no need for the parentheses on the end.

You need two steps:

var obj = {
    a : document.getElementById("ex1")
};

obj.b = obj.a.document.getElementsByTagName("div")

Or:

var temp = document.getElementById("ex1")
var obj = {
    a : temp,
    b : temp.document.getElementsByTagName("div")
};

When the property b is being defined, obj is not defined yet. One way to get around that problem is to make your property a function so that it's not evaluated until called.

var obj = {
    a : document.getElementById("ex1"),
    b : function() {
      // This is not evaluated until obj.b() is called
      return obj.a.document.getElementsByTagName("div");
    }
};
obj.b();

If you really want it to be a property, you have to do it in two steps as Tomasz Nurkiewicz shows

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