Property access

Learn dot and bracket notation for property access and when to use each.

Dot notation

To access a property of an object, use dot notation: write the object name, a dot, and the property name.

const user = { name: 'Alex', age: 28 };
user.name; // 'Alex'
user.age;  // 28

Dot notation is readable and ideal when you know the property name. The property name must be a valid identifier; it cannot contain spaces or hyphens.

Bracket notation

When the property name is stored in a variable or is not a valid identifier (has spaces or hyphens), use bracket notation.

const user = { 'full name': 'Alex Stone' };
const key = 'age';
user['full name']; // 'Alex Stone'
user[key];         // 28

Inside the brackets the key is written as a string. With a variable you skip the quotes, which makes dynamic access possible.

Exercise Calculate the total price

Access the price and quantity properties of the cart object below and assign their product to a total variable. Print total with console.log.

Show example solution

const cart = { price: 25, quantity: 4 };
const total = cart.price * cart.quantity;
console.log(total);

Test yourself

What does user.name return?
```
const user = { name: 'Alex', age: 28 };
user.name;
```
- 28
- undefined
- 'Alex'
- name
Show answer

'Alex' — Correct! user.name returns the value of the name property.

Access with a variable

const user = { age: 28 };
const key = 'age';
user____;

Show answer

const user = { age: 28 };
const key = 'age';
user[key];

Match each access form

user.name

dot notation
user['name']

bracket notation
user[key]

dynamic access

Next lesson: Adding and changing properties

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