Javascript: Access function within deep object on parse

Question

I have an object

var object1 = {
  object2: {
    function1: function(a, b, c, d, e) {
      //do some stuff with those parameters
      console.log('values are ' + a + ' ' + b + ' ' + c + ' ' + d);
    },
    function2: object1.object2.function1(2, 3, 4, 5)
  }
}

Why the line function2: object1.object2.function1(2, 3, 4, 5) line throws Uncaught TypeError: Cannot read property 'object2' of undefined and how can I make that work?

UPDATE: the answer is marked.

Thank you

`object1` and `object1.object2` aren't fully constructed at the time when you attempt to call `object1.object2.function1(...)`. Hence the error. — techfoobar, Jun 19 '15 at 12:08
What kind of problem are you trying to solve with that object structure, or are you just experimenting? — Andy, Jun 19 '15 at 12:10
possible duplicate of [Self-references in object literal declarations](http://stackoverflow.com/questions/4616202/self-references-in-object-literal-declarations) — Walter Chapilliquen - wZVanG, Jun 19 '15 at 12:10
@wZVanG thank you, I think that's what I need, I will test and let you all know. — thednp, Jun 19 '15 at 12:13

score 1 · Accepted Answer · answered Jun 19 '15 at 12:09

1

Because scope in which function2 is defined does not contain definition of object1. Then when you try to access object1.object2 it throws error because object1 is not defined

answered Jun 19 '15 at 12:09

David Votrubec

3,968
3
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Also the objects are not constructed on parse, only when invoked. – thednp Jun 21 '15 at 10:39

Margus · Answer 2 · 2015-06-19T12:21:48.310

Following would work:

var object1 = {
  object2: {
    function1: function(a, b, c, d, e) {
      //do some stuff with those parameters
      console.log('values are ' + a + ' ' + b + ' ' + c + ' ' + d);
    },
    function2: function(a, b, c, d, e) {
        object1.object2.function1(2, 3, 4, 5);
    }
  }
}
object1.object2.function2();

Basically at the time that you want to call object1 it does not yet exist. This is the reason you get this error. I just delayed this, by inserting it to a function and explicitly calling it later.

Note that javascript does no parameter checks, just fails if they mismatch.

Notice: function2 arguments are not used – Jan Turoň Jun 21 '15 at 09:13 — Jan Turoň, Jun 21 '15 at 09:13

score 1 · Answer 3 · answered Jun 19 '15 at 12:22

var object1 = {
    object2: {
        function1: function (a, b, c, d, e) {
            //do some stuff with those parameters
            console.log('values are ' + a + ' ' + b + ' ' + c + ' ' + d);
        },
        function2: function () { this.function1(2, 3, 4, 5); return this; }
    }.function2()
}
object1.object2.function1(9, 8, 7, 6, 5);

score 1 · Answer 4 · answered Jun 21 '15 at 09:11

1

If you want function2 as shorthand for function1 called with predefined arguments, you might use bind:

object1.object2.function2 = object1.object2.function1.bind(null, 2, 3, 4, 5)

if you need context, replace the null for object1.object2

answered Jun 21 '15 at 09:11

Jan Turoň

31,451
23
125
169

This seems useful. Thanks. – thednp Jun 21 '15 at 11:35

Javascript: Access function within deep object on parse

4 Answers4