JavaScript Program to Add Key/Value Pair to an Object

Example 1: Add Key/Value Pair to an Object Using Dot Notation

// program to add a key/value pair to an object

const person = {
    name: 'Monica',
    age: 22,
    gender: 'female'
}

// add a key/value pair
person.height = 5.4;

console.log(person);

Output

{
    name: "Monica",
    age: 22,
    gender: "female",
    height: 5.4
}

In the above example, we add the new property height to the person object using the dot notation . i.e. person.height = 5.4;.

Example 2: Add Key/Value Pair to an Object Using Square Bracket Notation

// program to add a key/value pair to an object

const person = {
    name: 'Monica',
    age: 22,
    gender: 'female'
}

// add a key/value pair
person['height'] = 5.4;

console.log(person);

Output

{
    name: "Monica",
    age: 22,
    gender: "female",
    height: 5.4
}

In the above example, we add the new property height to the person object using the square bracket notation [] i.e. person['height'] = 5.4;.

Also Read:

• JavaScript Program to Count the Number of Keys/Properties in an Object
• JavaScript Program to Create Objects in Different Ways