JavaScript · Chapter 13 of 55
JavaScript Objects
An object is a collection of key-value pairs, called properties. Objects let you group related data and behaviour together, modeling real-world things like a 'car' or a 'user'.
You can create objects with curly-brace literal syntax, and access their properties with dot notation or bracket notation.
Creating objects
`let car = { brand: 'Toyota', year: 2020 };` creates an object with two properties. Values can be any type, including functions and other objects.
Accessing properties
Use `car.brand` (dot notation) or `car['brand']` (bracket notation, useful for dynamic keys).
Example 1 (javascript)
let car = { brand: "Toyota", year: 2020 };
console.log(car.brand);
console.log(car["year"]);Output
Toyota
2020Both dot and bracket notation access the same properties.
Example 2 (javascript)
let person = { name: "Sam", greet() { return "Hi " + this.name; } };
console.log(person.greet());Output
Hi SamObjects can hold methods (functions as properties).
Key points
- Objects store data as key-value pairs called properties.
- Dot notation (`obj.key`) is the common access style.
- Bracket notation (`obj['key']`) supports dynamic or non-identifier keys.
- Object values can be functions, called methods.
💡 Note: Objects are reference types — copying a variable copies the reference, not the data.