add-update-delete-objects

Script

We already know that properties are the most important part of any JavaScript object. They are the values associated with an object.

Here, we will learn to add, update and delete properties of an Javascript Object.

Adding New Properties

There’re a few ways to add properties to an object in JavaScript. You can add new properties to an existing object by simply giving it a value.

Assume that you've an user object with the following definition:

const user = {
  name: "Virat",
  age: 32
};

One way to add a property to this user object is, by using the dot notation:

  user.email = "virat@gmail.com";

We've added the email property to the user object above with value virat@gmail.com.

We can also add a property, by using the bracket notation:

user['email'] = "virat@gmail.com";

It does the same thing as the previous example, but we can have invalid property identifiers with hyphen or space with this notation.

user['date-of-birth'] = "10-04-1990";

console.log(user.age)

Updating Property value

To update a property's value, simply assign it a new value. For example:

const virat = {
  name: "Virat",
  age: 32,
  email: "virat@gmail.com"
};

virat.age = 33

console.log(virat.age)

Deleting Property

The delete keyword deletes a property from an object, like:

const kohli = {
  name: "Virat Kohli",
  age: 32,
  email: "virat@gmail.com"
};

delete kohli.age;

This delete keyword deletes both the value of the property and the property itself. And, after deletion, if you would try to access the property, it would return undefined.