javascript how to simulate function global scope for Json statement?

Question

   var testJson=
    {
        a1: 1,
        a2: this.a1+1
    }

and the result should be:

var testJson=
{
    a1: 1,
    a2: 2
}

Do you mean var testJson= { a1: 1 }; testJson.a2 = testJson.a1 + 1;? What you want can only be done through a function call, but not object notation, at least not in a way you're looking to do...unless I'm completely misunderstanding. — Nick Craver
– Nick Craver, Commented May 21, 2010 at 18:47
@Nick Craver : You are right,I just want to wirte less code. the right way is: var testJson= { a1: 1, a2: testJson.a1+1 } — guaike
– guaike, Commented May 22, 2010 at 2:09

Jimmy · Accepted Answer · 2010-05-21 18:46:40Z

1

You'd have to either define a variable outside testJson, or use a function as the value of a2, like this:

var testJson = {
  a1: 1,
  a2: function () {
    return this.a1 + 1;
  }
};

answered May 21, 2010 at 18:46

Jimmy

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mattbasta · Accepted Answer · 2010-05-21 18:47:03Z

0

JSON does not support code execution. The JSON specification is simply a means for serializing and unserializing information for transport. There should be no executable content in a JSON string.

JSON parsers should fail when they encounter a non-literal value in a JSON string.

The only exception to this rule is with JSON-P, which wraps a JSON string in a function call in order to bypass cross-domain mechanisms.

answered May 21, 2010 at 18:47

mattbasta

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1 Comment

Pointy Over a year ago

Well, that's not really JSON, it's just Javascript syntax.

Sean Patrick Floyd · Accepted Answer · 2010-05-21 18:49:30Z

0

I don't think that's possible easily. It may be possible, but it would probably involve creating a function from an object and back again. This would be a lot easier:

var testJson=
{
    a1: 1,
    a2: function(){return this.a1+1}
}

which you could evaluate using

testJson.a2();

this should work out of the box

answered May 21, 2010 at 18:49

Sean Patrick Floyd

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