jquery - Javascript Dot Notation = Undefined - Stack Overflow

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Dot notation allows for accessing objects with a '.' Cannot figure out why this is happening. I have the following success function, as part of a jQuery $.ajax function.

success: function(data){
  console.log('data = ' + data);
  console.log('data.president = ' + data.president);
  console.log('data.adviser = ' + data.adviser);
}

This, oddly, results in the following browser log:

data = {"president":1,"adviser":1}
data.president = undefined
data.adviser = undefined

I must be missing something painfully obvious. Can somebody enlighten me?

Dot notation allows for accessing objects with a '.' Cannot figure out why this is happening. I have the following success function, as part of a jQuery $.ajax function.

success: function(data){
  console.log('data = ' + data);
  console.log('data.president = ' + data.president);
  console.log('data.adviser = ' + data.adviser);
}

This, oddly, results in the following browser log:

data = {"president":1,"adviser":1}
data.president = undefined
data.adviser = undefined

I must be missing something painfully obvious. Can somebody enlighten me?

• javascript
• jquery
• ajax
• syntax

Share Improve this question Follow edited Aug 15, 2017 at 21:39 Machavity♦ 31.7k2727 gold badges9595 silver badges105105 bronze badges asked Mar 8, 2016 at 15:25 cdwyercdwyer 69777 silver badges2323 bronze badges 5

• 3 I would suggest using mas in your console.log's instead of string concatenation. For example, see the difference between console.log('data = ' + {}) and console.log('data = ', {}) – Stryner Commented Mar 8, 2016 at 15:31
• data is a string. The point is that the console omits the " at the edges of it, making it resemble to an object, but it is not. It is the JSON serializazion of the object. Try add dataType: 'json' to the ajax request to convert it automatically to js object. – morels Commented Mar 8, 2016 at 15:37
• @Stryner Interesting. Can you elaborate on why mas are preferable? I ran that: concatenation returns data = [object Object] and mas return data = Object {} – cdwyer Commented Mar 8, 2016 at 15:38
• 2 Commas are preferable because they preserve the type of the objects being logged. With string concatenations, all objects will be changed to [object Type], which gives you less information. In the console I use (Firebug for Firefox), I'm able to inspect the object that's logged; I'm not sure if that's universal. – Stryner Commented Mar 8, 2016 at 15:44
• @Stryner very helpful, I appreciate the info. Thanks!! – cdwyer Commented Mar 8, 2016 at 15:45

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3 Answers 3

Sorted by: Reset to default 8

The data would have to be an Object to be accessed by a dot .. It's a string now. You need to parse it using for example:

data = JSON.parse(data);

Set dataType: "json" as ajax option so jQuery would parse your string data to javascript object

You define the data elements has strings, attributes of an object need to be declared without quotes, like this:

data = {president:1,adviser:1}

in that case you got the expected result

data.president = 1
data.adviser = 1

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