Javascript嵌套和调用对象

Question

I know I can nest objects in objects and recall to them easily example:

var ex1 = {
    data1: 1,
    dataOb: {
        data1: 2,
        data2: ex1.data1 + ex1.dataO.data1,
    }
}

And I can do console.log(ex1.dataO.data1) but I can't recall from dataOb to ex1.data1 example: data2: ex1.data1 + dataOb.data1 doesn't work, so my question is it possible to recall from DataOb to parental object ex1 ?

Answer 1

No. At the time that you're defining data2 , you're still in the middle of defining ex1 . That is, it doesn't really exist yet. You're trying to access it before you've even finished defining it.

Answer 2

If I understand you question rightly... do you want to use ex1.data1 in the same sentence you're creating the whole object?

This isn't ever possible!

You want to access to a reference that hasn't been created yet.

It's like doing this:

var a = a + 1;

How do you set the value of a plus 1 if a isn't declared already?!

Answer 3

You can do something like this:

var ex1 = {
  data1: 1,
  dataOb: {
    data1: 2,
    data2: 4
  },
  getSum: function () {
    var sum = 0;
    for ( var i = 0; i < arguments.length; i++ ) {
      sum += arguments[i];
    }

    return sum;

  }
};

console.log(ex1.getSum(ex1.data1, ex1.dataOb.data1)); // should log 3