The Methods Available on Session Storage in JavaScript

In web development, it is common to store data on the client-side to improve the user experience. One of the ways to achieve this is by using the sessionStorage object in JavaScript. The sessionStorage object allows developers to store key-value pairs in the user’s browser for the duration of the session. In this article, we will explore the methods available on sessionStorage, how to use them, and related concepts that can help us understand this topic better.

What is Session Storage?

Session storage is a type of web storage that allows developers to store data on the client-side temporarily. It is similar to local storage, but the data stored in session storage is cleared once the session ends. A session is defined as the time between the user opening a website and closing the website. During this time, the data stored in session storage is available to all pages in the same domain.

To use session storage, we can access the sessionStorage object in JavaScript. This object has several methods that we can use to interact with the data stored in session storage.

Methods Available on Session Storage

Here are the methods available on the sessionStorage object:

setItem()

The setItem() method allows us to add a key-value pair to session storage. The key is a string, and the value can be any data type that can be serialized to a string. If a key already exists in session storage, its value will be updated.

sessionStorage.setItem('name', 'John');

getItem()

The getItem() method allows us to retrieve the value of a key from session storage. If the key does not exist, the method will return null.

const name = sessionStorage.getItem('name');
console.log(name); // Output: "John"

removeItem()

The removeItem() method allows us to remove a key-value pair from session storage.

sessionStorage.removeItem('name');

clear()

The clear() method allows us to remove all key-value pairs from session storage.

sessionStorage.clear();

key()

The key() method allows us to retrieve the key at a specific index in session storage. The index is a number between 0 and sessionStorage.length - 1.

const key = sessionStorage.key(0);
console.log(key); // Output: "name"

length

The length property allows us to get the number of key-value pairs stored in session storage.

const count = sessionStorage.length;
console.log(count); // Output: 1

Related Concepts

Serialization

When we store data in session storage, we need to serialize it to a string. Serialization is the process of converting a data type into a string that can be stored or transmitted. In JavaScript, we can use the JSON.stringify() method to serialize an object or an array.

const data = { name: 'John', age: 30 };
const serializedData = JSON.stringify(data);
sessionStorage.setItem('data', serializedData);

Deserialization

When we retrieve data from session storage, we need to deserialize it back into its original data type. In JavaScript, we can use the JSON.parse() method to deserialize a JSON string into an object or an array.

const serializedData = sessionStorage.getItem('data');
const data = JSON.parse(serializedData);
console.log(data); // Output: { name: 'John', age: 30 }

Conclusion

In summary, the sessionStorage object in JavaScript allows developers to store data on the client-side temporarily. It has several methods that we can use to interact with the data stored in session storage, such as setItem(), getItem(), removeItem(), clear(), key(), and length. By understanding these methods and related concepts like serialization and deserialization, we can improve the user experience of our web applications.