Dynamically name a JSON property

Question

I've been trying to create a dynamically named JSON property but I keep hitting on errors. Honestly I don't know if this is possible to achieve with Javascript. Anyway here is my problem.

Let's suppose I'm creating a JSON object like the following code:

var DTO = { 'NewObject' : GetFormData() };  
var DTO = { 'UpdateObject' : GetFormData() };  
var DTO = { 'DelObject' : GetFormData() };

Now what I've been trying to do is to dynamically name the JSON property because with something like 'New' + ClassName (ClassName being a var with a string value) but it gives me a syntax error. Is there a way to do this to become something like:

var DTO = { 'New' + ClassName : GetFormData() };  
var DTO = { 'Update' + ClassName : GetFormData() };  
var DTO = { 'Delete' + ClassName : GetFormData() };

I really appreciate your help. Thanks.

instanceof me · Accepted Answer · 2010-02-23 13:50:46Z

44

Would this suit your needs ?

var DTO = {}; DTO['New' + ClassName] = GetFormData();

answered Feb 23, 2010 at 13:50

instanceof me

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Dylan Hogg · Accepted Answer · 2017-06-20 21:17:31Z

22

With ECMAScript 6, you can use computed property names in object property definitions.

For example, you can simply write:

var DTO = { ['New' + ClassName] : GetFormData() };

More information: http://es6-features.org/#ComputedPropertyNames

answered Jun 20, 2017 at 21:17

Dylan Hogg

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Quentin · Accepted Answer · 2010-02-23 13:49:25Z

12

This is just "an object". JSON is a serialization to a string, not an object type.

If you want to use a variable as a property name, then you must create an object first, then assign the data using square bracket notation.

var foo = {};
var bar = 'baz';
foo[bar] = '123';
alert(foo.baz);

answered Feb 23, 2010 at 13:49

Quentin

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Ignacio Vazquez-Abrams · Accepted Answer · 2010-02-23 13:49:57Z

3

var DTO = Object();
DTO['New' + ClassName] = GetFormData();

answered Feb 23, 2010 at 13:49

Ignacio Vazquez-Abrams

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Abhishek Mishra · Accepted Answer · 2023-05-16 10:21:40Z

0

If someone needs to keep previous data too, then use the below code:

var DTO = {}; 
DTO = {...DTO,['New' + ClassName] = GetFormData()}
DTO = {...DTO,['Update' + ClassName] = GetFormData()}

Final DTO will store both the New & Update fields.

answered May 16, 2023 at 10:21

Abhishek Mishra

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