Get json value by json key if the key name is variable value

Question

I have json string and want to get a value by key, but key name is value of some variable. To resolve the issue I've found this

window[varName]

and tried to use as following

<script>
var jsonStr = '{"someProperty":"Value of someProperty","somePropertyAndSuffix":"Value of somePropertyAndSuffix"}';
var jsonObj = JSON.parse(jsonStr);

var propAsString = 'someProperty';

console.log(jsonObj.window[propAsString]);
console.log(jsonObj.window[propAsString]+'AndSuffix');
</script>

but I get the error

Uncaught TypeError: Cannot read property 'someProperty' of undefined

If I try

console.log(jsonObj[window[propAsString]]);
console.log(jsonObj[window[propAsString]+'AndSuffix']);

I get two undefined

First of all, window property is not defined in jsonObj. 2nd, you should do jsonObj[propAsString + 'AndSuffix'] — Mr.DeleteMyMessages
– Mr.DeleteMyMessages, Commented Dec 26, 2018 at 18:26
If you know jsonObj and propAsString are defined, you can just do jsonObj[propAsString] — blex
– blex, Commented Dec 26, 2018 at 18:28

Mathias W · Accepted Answer · 2018-12-26 18:32:47Z

2

Remove window and it will work. jsonObj would be accessible on window (window.jsonObj) as javascript is hoisting the assignments with var to the closest scope (in this case the window).

var jsonStr = '{"someProperty":"Value of someProperty","somePropertyAndSuffix":"Value of somePropertyAndSuffix"}';
var jsonObj = JSON.parse(jsonStr);

var propAsString = 'someProperty';

console.log(jsonObj[propAsString]);
console.log(jsonObj[propAsString + 'AndSuffix']);

edited Dec 26, 2018 at 18:32

answered Dec 26, 2018 at 18:29

Mathias W

1,56113 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Mr.DeleteMyMessages · Accepted Answer · 2018-12-26 18:31:01Z

2

I'm not sure if I correctly understand this, but this is how to solve this:

const jsonStr = '{"someProperty":"Value of someProperty","somePropertyAndSuffix":"Value of somePropertyAndSuffix"}'
const obj = JSON.parse(jsonStr)
const propAsString = 'someProperty'
console.log(obj[propAsString], obj[propAsString + 'AndSuffix'])

answered Dec 26, 2018 at 18:31

Mr.DeleteMyMessages

3814 silver badges11 bronze badges

Collectives™ on Stack Overflow

Get json value by json key if the key name is variable value

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related