Access the First Property of an Object in JavaScript

In this blog, lets see several ways in which you can get the first property of an Object in Javascript:

⚠ Caution: Order not guaranteed

⚠ In JavaScript, object properties are not guaranteed to have a specific order. The ECMAScript specification does not define a specific order for object properties, and the iteration order can vary between different JavaScript engines.

While modern JavaScript engines, like those in browsers, often maintain insertion order for object properties, it’s essential to understand that this behavior is not mandated by the language specification. The order in which properties are iterated over during operations like for…in loop or Object.keys() may not always match the order in which they were added to the object.

If you rely on a specific order of properties, it’s recommended to use an array or another data structure that explicitly maintains order. For unordered key-value pairs, objects are commonly used, but developers should be cautious about relying on property order in scenarios where order is crucial to the application logic.

Dot Notation

Directly access the first property of an object using dot notation.

let myObject = { first: 'Hello', second: 'World' };
let firstProperty = myObject.first;
console.log("First Property:", firstProperty);

Bracket Notation

Employ bracket notation for dynamic access to the first property of an object.

let myObject = { first: 'Hello', second: 'World' };
let firstProperty = myObject['first'];
console.log("First Property:", firstProperty);

ES6 Destructuring Assignment

Unpack the first property using destructuring assignment.

let myObject = { first: 'Hello', second: 'World' };
let { first: firstProperty } = myObject;
console.log("First Property:", firstProperty);

Optional Chaining (ES11+)

Safely access the first property, even if the object is undefined or null.

let myObject = { first: 'Hello', second: 'World' };
let firstProperty = myObject?.first;
console.log("First Property:", firstProperty);

for…in loop

Traverse an object and access its first property using the for…in loop.

let myObject = { first: 'Hello', second: 'World' };
let firstProperty;
for (let key in myObject) {
  firstProperty = myObject[key];
  break;
}
console.log("First Property:", firstProperty);

lodash.find()

Leverage lodash to find and access the first property of an object.

const _ = require('lodash');
let myObject = { first: 'Hello', second: 'World' };
let firstProperty = _.find(myObject);
console.log("First Property:", firstProperty);

Object.entries()

Uncover the first property of an object using Object.entries().

let myObject = { first: 'Hello', second: 'World' };
let firstProperty = Object.entries(myObject)[0][1];
console.log("First Property:", firstProperty);

🧪Practice Coding Problem: Get First Property

In the spirit of Test Driven Development ( 😁), lets test our understanding by solving a problem.

Create a function that takes an object and returns the value of its first property.

JavaScript

let sampleObject = { first: 'Greetings', second: 'Earthling' };

function getFirstPropertyValue(obj) {
  // > > > 👉 Write code here 👈 < < <
}

console.log(getFirstPropertyValue(sampleObject)); 
// Expected Output: 'Greetings'

function getFirstPropertyValue(obj) {
  return obj?.[Object.keys(obj)[0]];
}

BTW, do you know why the JavaScript date refuse to go to the party? It heard they needed a timestamp, not a time-stampede. 😉

Happy coding 🚀!