Object literal

Learn to create objects with {}.

Object literal

An object groups related data under a single value. The simplest form is the object literal: key-value pairs inside curly braces.

The syntax is { key: value }. In each pair key is the property name and value is the value assigned to it. Multiple pairs are separated by commas. Example: { name: 'Ayşe', age: 30 } is an object with two properties.

Property names are usually strings; values can be anything: numbers, strings, arrays, even other objects. This flexibility makes objects a powerful tool for modelling data.

Property and value

Each pair inside an object is called a property. The left side is the name, the right side is the value. The value can change later; the name stays fixed after the object is created.

Even if you declare the object with const, its property values can still change. const only fixes the variable binding; it does not freeze the object. Example: const user = { name: 'Ayşe' }; user.name = 'Mara'; is valid.

A property name can also be a number, boolean, or variable; JavaScript converts it to a string automatically. So { 1: 'a' } and { '1': 'a' } are the same object.

Exercise Print a user object

Define a user object with name set to 'Ayşe' and age set to 30. Print the name property with console.log.

Show example solution

const user = { name: 'Ayşe', age: 30 };
console.log(user.name);

Test yourself

Which object literal is valid?
- { 'name': 'Ayşe' }
- { name: 'Ayşe' }
- { name = 'Ayşe' }
- { name -> 'Ayşe' }
Show answer

{ 'name': 'Ayşe' } — quoting the key is also valid; the separator is a colon.

User object

const user = { name: ____, age: 28 };

Show answer

const user = { name: 'Ayşe', age: 28 };

Match the object parts

{ }

Object start and end
name

Property name
'Ayşe'

Property value
:

Name-value separator

Next lesson: Property access

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