How to Access the First Property of a JavaScript Object

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.

Get value of first object property

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

How can I access the first property of a nested property?

Use Object.values() to convert the object to an array, then get the first value.

Object.values(pages)[0]

Getting the first index of an object

If the order of the objects is significant, you should revise your JSON schema to store the objects in an array:

[
    {"name":"foo", ...},
    {"name":"bar", ...},
    {"name":"baz", ...}
]

or maybe:

[
    ["foo", {}],
    ["bar", {}],
    ["baz", {}]
]

As Ben Alpert points out, properties of Javascript objects are unordered, and your code is broken if you expect them to enumerate in the same order that they are specified in the object literal—there is no "first" property.

JavaScript: 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

Get the first key name of a JavaScript object

In Javascript you can do the following:

Object.keys(ahash)[0];

javascript's object: Get only the first key of an object

You can use Object.keys():

The Object.keys() method returns an array of a given object's own property names, in the same order as we get with a normal loop.

Then take the key from first index.

var p = {    "p1": "value1",    "p2": "value2",    "p3": "value3"};var objectKey = Object.keys(p)[0];

 console.log("the first key is: "  + objectKey)

Get first property of an object that matches the condition

I’m glad you’re using ES6. In this case you can use Object.keys to get an array of all the object’s keys and Array.prototype.find to find the first element with a specific property:

var obj = {
  a: [],
  b: [],
  c: [
    2,
    3
  ],
  d: [],
  e: [
    1
  ]
};

Object.keys(obj).find(a => obj[a].length > 0); // The letter "c" which contains the first non-empty array.

obj[Object.keys(obj).find(a => obj[a].length > 0)]; // Array [2, 3] itself

Note that there’s no consistent “first” element in an object across implementations.

The easiest way to access an object's single own property?

something like

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

getting the keys with Object.keys and the first (and only) key with [0]

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