JavaScript Object Methods & this Keyword Explained

What is an Object Method?

An object method is a function stored inside an object. It allows the object to perform actions using its own data.

1. Defining Object Methods

Example:

let person = {
  firstName: "Alice",
  lastName: "Smith",
  fullName: function () {
    return this.firstName + " " + this.lastName;
  }
};

console.log(person.fullName());

Output

this refers to the object (person) that owns the method.

2. The this Keyword in Object Methods

Example:

let car = {
  brand: "Tesla",
  model: "Model 3",
  showInfo: function () {
    console.log("Car: " + this.brand + " " + this.model);
  }
};

car.showInfo();

Output

this.brand refers to car.brand.

3. Arrow Functions and this Inside Objects

Arrow functions do not have their own this — they inherit this from the outer scope.

Example:

let user = {
  name: "John",
  sayHi: () => {
    console.log("Hi " + this.name);
  }
};

user.sayHi();

Output

Use regular functions (not arrow functions) for methods to access this correctly.

4. Shorthand Method Syntax (ES6)

You can define object methods more cleanly using shorthand.

Example:

let dog = {
  name: "Buddy",
  bark() {
    return this.name + " says woof!";
  }
};

console.log(dog.bark());

Output

5. Method Reuse with this

You can reuse methods across multiple objects using this.

Example:

function greet() {
  console.log("Hello, I am " + this.name);
}

let user1 = { name: "Ava", greet: greet };
let user2 = { name: "Liam", greet: greet };

user1.greet();  // Hello, I am Ava
user2.greet();  // Hello, I am Liam

Summary Table – Object Methods & this