How to Create a Login Page In ReactJs

Creating a login page is a crucial aspect of web development, and ReactJS is a popular Javascript library that can help you achieve it. In this article, we will go over the steps required to create a login page using ReactJS, along with examples and explanations.

Firstly, it's important to understand what ReactJS is. ReactJS is a Javascript library used for creating user interfaces, primarily in front-end development. It offers various features, such as interactive UI components, making it a popular choice for web developers.

To create a login page, we need to add a container component to our React app. A container component is a parent element that links standard components to the logic that makes the UI interactive and dynamic. In our example, we will create a new file called "Login.js" and add the following code:

javascript
import React, { useState } from "react";
import Form from "react-bootstrap/Form";
import Button from "react-bootstrap/Button";
import "./Login.css";

export default function Login() {
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");

  function validateForm() {
    return email.length > 0 && password.length > 0;
  }

  function handleSubmit(event) {
    event.preventDefault();
  }

  return (
    <div className="Login">
      <Form onSubmit={handleSubmit}>
        <Form.Group size="lg" controlId="email">
          <Form.Label>Email</Form.Label>
          <Form.Control
            autoFocus
            type="email"
            value={email}
            onChange={(e) => setEmail(e.target.value)}
          />
        </Form.Group>
        <Form.Group size="lg" controlId="password">
          <Form.Label>Password</Form.Label>
          <Form.Control
            type="password"
            value={password}
            onChange={(e) => setPassword(e.target.value)}
          />
        </Form.Group>
        <Button block size="lg" type="submit" disabled={!validateForm()}>
          Login
        </Button>
      </Form>
    </div>
  );
}

Here, we have used the useState hook to save the user's email and password input in the form. The validateForm function checks if the email and password fields are not empty, and the handleSubmit function prevents the default form submission when the form is submitted.

We have also added the autoFocus flag to the email field, which focuses on the email field when the form is loaded. The Form.Control component from the react-bootstrap library is used to create the form controls, which display the value of the email and password state variables. This is known as a Controlled Component pattern in React.

Next, we need to add a route to connect our Login component to the rest of the project. We can use the React Router library for routing in our React app. Below the home <Route>, we add the following code to "Routes.js":

php
<Route exact path="/login">
  <Login />
</Route>

Also, make sure to include the Login component in the header by importing it:

python
import Login from "./containers/Login";

With these steps, we have successfully created a login page in ReactJS. Users can now enter their email and password, and the validateForm function checks if the fields are not empty. When the form is submitted, the handleSubmit function is called, and we can then authenticate the user using the entered credentials.

Creating a Login Page with React and Node.js

In today's digital era, it is imperative to have a secure login system for web applications. This article will provide a step-by-step guide on how to build a login page using React and Node.js. We will be using Create React App to set up the development environment and React Router to create different routes for our components. In addition, we will create a local API using Node.js and Express to retrieve user tokens for secure login.

Prerequisites: Before starting the project, you should have a good understanding of HTML, CSS, and JavaScript. Additionally, you'll need a Node.js development environment with version 10.22.0 of Node.js and version 6.14.6 of npm installed.

Step 1: Building a Login Page First, we will create a login page for our application using React Router. Install React Router using npm:

npm install react-router-dom

After installing, create two components called Dashboard and Preferences, which are private pages that should only be shown to users who have successfully signed in. Create these components using the following commands:

bash
mkdir src/components/Dashboard
mkdir src/components/Preferences

Then, open Dashboard.js using a text editor such as Nano:

bash
nano src/components/Dashboard/Dashboard.js

In the text editor, create a h2 tag in Dashboard.js:

javascript
import React from 'react';
export default function Dashboard() {
  return(
    <h2>Dashboard</h2>
  );
}

Do the same for Preferences.

Next, import Dashboard and Preferences in App.js and define routes using BrowserRouter, Switch, and Route:

javascript
import React from 'react';
import './App.css';
import { BrowserRouter, Route, Switch } from 'react-router-dom';
import Dashboard from '../Dashboard/Dashboard';
import Preferences from '../Preferences/Preferences';

function App() {
  return (
    <>
      <BrowserRouter>
        <Switch>
          <Route path='/dashboard' component={Dashboard} />
          <Route path='/preferences' component={Preferences} />
        </Switch>
      </BrowserRouter>
    </>
  );
}

export default App;

Finally, add padding to the main div to ensure that the component does not sit directly on the browser's edge. Update the CSS to accomplish this:

bash
nano src/components/App/App.css

Then add the following code to the .wrapper class with a 20px padding:

css
.wrapper {
    padding: 20px;
}

Step 2: Creating a Token API Next, we'll construct a local API to get a user token. We will use Node.js and Express to create a mock API that returns a token. After successfully retrieving the token, we'll use that API from our login page and render the component.

Install Express and cors using npm:

css
npm install --save-dev express cors

Create a new file named server.js at the root of our application, and import Express and cors:

javascript
const express = require('express');
const cors = require('cors');
const app = express();

app.use(cors());

app.use('/login', (req, res) => {
  res.send({
    token: 'test123'
  });
});

app.listen(8080, () => console.log('API is running on http://localhost:8080/login'));

This will create a local server that listens on the /login path and returns a JavaScript object holding a token.

To use this API from our login page, we'll create a new component called Login.js. In this component, we will make an HTTP request to our API and retrieve the user token:

jsx
import React, { useState } from 'react';
import axios from 'axios';

function Login() {
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');

  const handleEmailChange = (event) => setEmail(event.target.value);
  const handlePasswordChange = (event) => setPassword(event.target.value);

  const handleSubmit = async (event) => {
    event.preventDefault();
    try {
      const response = await axios.post('http://localhost:3001/login', {
        email,
        password,
      });
      const token = response.data.token;
      console.log(token);
      // save token to local storage or redux state for later use
    } catch (error) {
      console.log(error);
    }
  };

  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label>Email</label>
        <input type="email" value={email} onChange={handleEmailChange} />
      </div>
      <div>
        <label>Password</label>
        <input type="password" value={password} onChange={handlePasswordChange} />
      </div>
      <button type="submit">Login</button>
    </form>
  );
}

export default Login;

In this component, we use the useState hook to create state variables for the user's email and password. We also create two event handlers to update these variables when the user types in the email and password fields.

When the user submits the form, we make an HTTP POST request to the /login endpoint of our API using the axios library. We pass in the user's email and password as the request body. If the request is successful, we retrieve the token from the response and log it to the console. In a real application, we would save the token to local storage or redux state for later use.

If there is an error during the request, we log the error to the console.

With this component, we have created a simple login page that communicates with our server-side API to retrieve a user token. We can now integrate this component into our application and use the token to authenticate the user for protected routes or API calls.

Authentication is a crucial feature of any website, particularly those that include private pages requiring user login. Storing a user token is a critical step in the authentication process, and in this article, we'll explore various methods of storing user tokens, along with the security implications and user experience associated with each.

There are four primary methods for storing user tokens: saving in JavaScript memory, sessionStorage, localStorage, and cookie storage. The primary trade-off among these methods is security. Non-memory storage solutions like sessionStorage and localStorage provide the advantage of reducing the number of times a user must log in, resulting in a better user experience, but they also increase the risk of Cross-Site Scripting (XSS) attacks. On the other hand, saving tokens in JavaScript memory provides better security but may require the user to log in more frequently.

We'll focus on the use of localStorage in this article, which saves data long after the session has ended. While this approach is more convenient, it also has certain security issues. For example, if the user shares their computer, even if they close the browser, they will remain logged in to the application, and the next user would have immediate access to the application without requiring a login.

To implement token storage using localStorage, we can modify the useToken() function in our App component by replacing any references to sessionStorage with localStorage. We can also create a custom Hook to shift component logic to a different function, which can make a component re-render happen.

Once we've implemented localStorage, the user will remain logged in even when they open a new tab or window, as long as they're using the same computer. However, they will need to explicitly log out to protect their privacy.

In conclusion, we've explored the different methods of storing user tokens and their security implications, as well as the advantages and disadvantages of each method in terms of user experience. By focusing on validating data and rendering components at the appropriate times, we can create a simple yet effective authentication process for our users. It's crucial to keep in mind that security and convenience are often in tension, and finding the right balance between the two is essential to creating a successful authentication system.