JavaScript Methods and this Keyword

Manikandan K - Jun 8 '22 -

- Dev Community

OBJECT METHODS

JavaScript Object contains a function as a value in a key/name.
Simply, JavaScript Method is an Object property that has a function.

Syntax

const object_name = {
    key_1: value_1;
    key_2: value_2
    key_3: function() {
        // code to be execute.
    }   
}

Accessing Methods
We know how to access an object and how to call a function. Both will combine we can access the JavaScript method.

Syntax

objectName.key(or)method name();

NOTE :
To access the methods, we put must () end of the method name.

Example

const person = {
  name: 'Manikandan',
  age: 24,
  sayHello: function () {
    console.log('Hello Manikandan');
  },
};

// ** access property
console.log(person.name); // Manikandan

// ** access property as well as function in an object.
console.log(person.sayHello); // [Function: sayHello]

// ** access method
person.sayHello(); // Hello Manikandan

'this' key word

To access a property of an object from within a method of the same object,
we use this keyword.

const person = {
    name: 'Manikandan',
    age: 23,
    sayHello: function() {
        console.log(`Hi, This is ${this.name}. I am ${this.age} yrs old`);
    }
}

person.sayHello();

here,
sayHello method(person.sayHello) needs to access name property in same object(person.name).
Both of the same Object.(person) so we used this keyword here.