JavaScript – How to Get Value of First Object Property

javascriptobject

I have a simple object that always has one key:value like var obj = {'mykey':'myvalue'}

What is the fastest way and elegant way to get the value without really doing this?

for (key in obj) {
  console.log(obj[key]);
  var value = obj[key];
}

Like can I access the value via index 0 or something?

Best Answer

var value = obj[Object.keys(obj)[0]];

Object.keys is included in javascript 1.8.5. Please check the compatibility here http://kangax.github.io/es5-compat-table/#Object.keys

Edit:

This is also defined in javascript 1.8.5 only.

var value = obj[Object.getOwnPropertyNames(obj)[0]];

Reference:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects?redirectlocale=en-US&redirectslug=JavaScript%2FGuide%2FWorking_with_Objects#Enumerating_all_properties_of_an_object

Related Solutions

JavaScript – How to Access the First Property of a JavaScript Object

var obj = { first: 'someVal' };
obj[Object.keys(obj)[0]]; //returns 'someVal'

Object.values(obj)[0]; // returns 'someVal'

Using this you can access also other properties by indexes. Be aware tho! Object.keys or Object.values return order is not guaranteed as per ECMAScript however unofficially it is by all major browsers implementations, please read https://stackoverflow.com/a/23202095 for details on this.

JavaScript Object – Get First and Only Property Name of Object

Maybe Object.keys can work for you. If its length returns 1, you can use yourObject[Object.keys[0]] to get the only property of the object. The MDN-link also shows a custom function for use in environments without the keys method¹. Code like this:

var obj = {foo:'bar'}, 
    kyz = Object.keys(obj);
if (kyz.length === 1){
   alert(obj[kyz[0]]); //=> 'bar'
} else {
  /* loop through obj */
}

¹ Some older browsers don't support Object.keys. The MDN link supplies code to to make it work in these browsers too. See header Compatibility in the aforementioned MDN page

Best Answer

Related Solutions

JavaScript – How to Access the First Property of a JavaScript Object

JavaScript Object – Get First and Only Property Name of Object

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