published: 19 Aug 2022
2 min read
How to add a property to an object in JavaScript
To add a new property to a JavaScript object:
- You either use the dot (
.) notation or the square bracket ([]). - In dot donation, you use the object name followed by the dot, the name of the new property, an equal sign, and the value for the new property.
- In square bracket notation, you use the property name as a key in square bracket followed by an equal sign and the value of the new property.
A JavaScript object is a collection of key-value pairs called properties. Unlike arrays, objects don't provide an index to access the properties.
You can either use the dot (.) notation or the square bracket ([]) notation to access property values.
const foods = { burger: '🍔', pizza: '🍕' };
// Dot Notation
console.log(foods.burger); // 🍔
// Square Bracket Notation
console.log(foods['pizza']); // 🍕
The simplest and most popular way is to use the dot notation to add a new key-value pair to an object:
foods.custard = '🍮';
console.log(foods);
// { burger: '🍔', pizza: '🍕', custard: '🍮' }
Alternatively, you could also use the square bracket notation to add a new item:
foods['cake'] = '🍰';
console.log(foods);
// { burger: '🍔', pizza: '🍕', cake: '🍰' }
As you can see above, when you add a new item to an object, it usually gets added at the end of the object.
To learn more about JavaScript objects, prototypes, and classes, read this article.
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How to add a property to an object in JavaScript
To add a new property to a JavaScript object:
- You either use the dot (
.) notation or the square bracket ([]). - In dot donation, you use the object name followed by the dot, the name of the new property, an equal sign, and the value for the new property.
- In square bracket notation, you use the property name as a key in square bracket followed by an equal sign and the value of the new property.
A JavaScript object is a collection of key-value pairs called properties. Unlike arrays, objects don't provide an index to access the properties.
You can either use the dot (.) notation or the square bracket ([]) notation to access property values.
const foods = { burger: '🍔', pizza: '🍕' };
// Dot Notation
console.log(foods.burger); // 🍔
// Square Bracket Notation
console.log(foods['pizza']); // 🍕
The simplest and most popular way is to use the dot notation to add a new key-value pair to an object:
foods.custard = '🍮';
console.log(foods);
// { burger: '🍔', pizza: '🍕', custard: '🍮' }
Alternatively, you could also use the square bracket notation to add a new item:
foods['cake'] = '🍰';
console.log(foods);
// { burger: '🍔', pizza: '🍕', cake: '🍰' }
As you can see above, when you add a new item to an object, it usually gets added at the end of the object.
To learn more about JavaScript objects, prototypes, and classes, read this article.
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JS Nooby
Javascript connoisseur
