React Cookies: A Comprehensive Guide to Storing Data with Cookies

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Cookies are a simple and effective way to store data on the client-side of a web application. They allow you to store small pieces of information that can be accessed by the server or client-side scripts, making them a useful tool for storing user preferences, tracking user sessions, and more.

But how do you use cookies with React, and when should you choose cookies over other storage options like web storage or local storage? In this article, we’ll explore these questions and more as we dive into the world of cookies with React.

What you can do with Cookies

Cookies are a common feature of web applications, and they can be very useful for storing small pieces of information on the client side. Before we look at how to leverage cookies, let’s check out some of the common use cases for cookies:

1. Storing user preferences: Cookies can be used to store user preferences such as the language or theme of a web application. This allows users to customize their experience and have their preferences persist across multiple visits.
2. Persisting user sessions: Cookies can be used to store session information, allowing users to remain logged in to a web application even after closing their browser. This can be particularly useful for applications that require a high level of security, such as financial or healthcare applications.
3. Tracking user activity: Cookies can be used to track user activity, such as the pages they visit or the products they view on an e-commerce website. This information can be used to personalize the user experience, show targeted advertisements, or analyze user behavior.
4. Implementing authentication: Cookies can be used to implement authentication in a web application. When a user logs in, a cookie containing their authentication information can be set, and this cookie can be checked on subsequent requests to determine if the user is logged in.
5. Enabling third-party integration: Cookies can be used to enable integration with third-party services, such as social media networks or analytics tools. By storing information in a cookie, these services can track user activity and provide additional functionality to your application.

How Cookies actually work

Cookies are small pieces of data that are stored in the user’s browser and can be accessed by the server or client-side scripts. They are typically used to store user preferences, track user sessions, and store small amounts of data.

Cookies are stored in the form of key-value pairs, with the key being the name of the cookie and the value being the data stored in the cookie. Cookies are sent to the server with every HTTP request and can be accessed by the server or client-side scripts using the document.cookie property.

Cookies have a number of attributes that can be set to control their behavior. These attributes include:

• expires: The date at which the cookie expires and is deleted from the user's browser.
• max-age: The maximum age of the cookie in seconds.
• path: The path on the server to which the cookie is sent.
• secure: A flag indicating whether the cookie should only be sent over secure connections.
• httpOnly: A flag indicating whether the cookie should only be accessed by the server.

Using Cookies in React

So how do you use cookies in a React application? There are a few different approaches you can take, but one of the simplest is to use the js-cookie library. This library provides a simple API for reading, writing, and deleting cookies in your React components.

To use js-cookie in your React application, you'll need to install the library first:

npm install js-cookie

Once the library is installed, you can import it into your React components and use its methods to read, write, and delete cookies. Here’s an example of how to use js-cookie to read a cookie in a React component:

import Cookies from 'js-cookie';

function MyComponent() {
  const name = Cookies.get('name');
  return (
    <div>
      <p>Your name is: {name}</p>
    </div>
  );
}

In this example, the Cookies.get method is used to read the name cookie from the user's browser. The value of the cookie is then displayed in a paragraph element.

You can also use the Cookies.set method to write a cookie in a React component:

import Cookies from 'js-cookie';

function MyComponent() {
  const [name, setName] = useState(Cookies.get('name') || '');
  const handleChange = e => {
    setName(e.target.value);
  };
  const handleSubmit = e => {
    e.preventDefault();
    Cookies.set('name', name);
  };
  return (
    <form onSubmit={handleSubmit}>
      <input value={name} onChange={handleChange} />
      <button type="submit">Save</button>
    </form>
  );
}

In this example, the Cookies.set method is used to write the name cookie to the user's browser when the form is submitted. The name value is stored in the cookie with a default expiration date of one year.

You can also use the Cookies.remove method to delete a cookie in a React component:

import Cookies from 'js-cookie';

function MyComponent() {
  const handleClick = () => {
    Cookies.remove('name');
  };
  return (
    <button onClick={handleClick}>Clear</button>
  );
}

In this example, the Cookies.remove method is used to delete the name cookie from the user's browser when the button is clicked.

It’s important to note that cookies have size limits and can only store strings. If you need to store large amounts of data or data of other types, you may need to use a different storage option such as local storage or a database.

Choosing Between Cookies, Web Storage, and Local Storage

So now that you know how to use cookies with React, how do you choose between cookies, web storage, and local storage? Here are a few factors to consider:

• Scope: Cookies are sent to the server with every HTTP request, making them a useful tool for storing data that needs to be accessed by the server. Web storage and local storage, on the other hand, are stored on the client-side and are not sent to the server with HTTP requests.
• Lifetime: Cookies can have an expiration date or a maximum age set, while web storage and local storage are persistent. Choose cookies if you need to store data for aspecific period of time, and choose web storage or local storage if you need to store data indefinitely.
• Size: Cookies have a maximum size of around 4KB, while web storage and local storage have larger limits of around 5MB and 10MB, respectively. Choose cookies if you only need to store small amounts of data, and choose web storage or local storage if you need to store larger amounts of data.
• Security: Cookies are sent to the server with every HTTP request and are stored on the client-side, making them less secure than web storage and local storage. If you need to store sensitive data, it’s best to use web storage or local storage.

Wrapping Up

Cookies are a powerful tool for storing small pieces of information on the client side and can be used in a variety of ways in a React application. Whether you’re looking to store user preferences, persist user sessions, track user activity, implement authentication, or enable third-party integration, cookies can be a useful addition to your toolkit.

We hope this comprehensive guide to cookies with React has given you a better understanding of how to use cookies in your applications. With the power of cookies at your fingertips, you’ll be able to create user-friendly and functional React applications that will delight your users.