Tutorial: Prepare a React single-page app (SPA) for authentication in a customer tenant

Article
11/27/2023

In the previous article, you registered an application and configured user flows in your Microsoft Entra ID for customers tenant. This tutorial demonstrates how to create a React single-page app using npx and create files needed for authentication and authorization.

In this tutorial;

Create a React project in Visual Studio Code
Install identity and bootstrap packages
Configure the settings for the application

Prerequisites

Completion of the prerequisites and steps in Prepare your customer tenant to authenticate users in a React single-page app (SPA).
Although any integrated development environment (IDE) that supports React applications can be used, this tutorial uses Visual Studio Code. You can download it here.
Node.js.

Create a React project

Open Visual Studio Code, select File > Open Folder.... Navigate to and select the location in which to create your project.
Open a new terminal by selecting Terminal > New Terminal.
Run the following commands to create a new React project with the name reactspalocal, change to the new directory and start the React project. A web browser will open with the address http://localhost:3000/ by default. The browser remains open and re-renders for every saved change.
```
npx create-react-app reactspalocal
cd reactspalocal
npm start
```

Create additional folders and files to achieve the following folder structure:

reactspalocal
├─── public
│   └─── index.html
└───src
    ├─── components
    │   └─── DataDisplay.jsx
    │   └─── NavigationBar.jsx
    │   └─── PageLayout.jsx
    └───styles
    │   └─── App.css
    │   └─── index.css
    └─── utils
    │    └─── claimUtils.js
    └── App.jsx
    └── authConfig.js
    └── index.js

Install app dependencies

Identity related npm packages must be installed in the project to enable user authentication. For project styling, Bootstrap is used.

In the Terminal bar, select the + icon to create a new terminal. A new terminal window will open enabling the other terminal to continue running in the background.
If necessary, navigate to reactspalocal and enter the following commands into the terminal to install the msal and bootstrap packages.
```
npm install @azure/msal-browser @azure/msal-react
npm install react-bootstrap bootstrap
```

Create the authentication configuration file, authConfig.js

In the src folder, open authConfig.js and add the following code snippet:

/*
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License.
 */

import { LogLevel } from '@azure/msal-browser';

/**
 * Configuration object to be passed to MSAL instance on creation. 
 * For a full list of MSAL.js configuration parameters, visit:
 * https://github.com/AzureAD/microsoft-authentication-library-for-js/blob/dev/lib/msal-browser/docs/configuration.md 
 */

export const msalConfig = {
    auth: {
        clientId: 'Enter_the_Application_Id_Here', // This is the ONLY mandatory field that you need to supply.
        authority: 'https://Enter_the_Tenant_Subdomain_Here.ciamlogin.com/', // Replace the placeholder with your tenant subdomain 
        redirectUri: '/', // Points to window.location.origin. You must register this URI on Azure Portal/App Registration.
        postLogoutRedirectUri: '/', // Indicates the page to navigate after logout.
        navigateToLoginRequestUrl: false, // If "true", will navigate back to the original request location before processing the auth code response.
    },
    cache: {
        cacheLocation: 'sessionStorage', // Configures cache location. "sessionStorage" is more secure, but "localStorage" gives you SSO between tabs.
        storeAuthStateInCookie: false, // Set this to "true" if you are having issues on IE11 or Edge
    },
    system: {
        loggerOptions: {
            loggerCallback: (level, message, containsPii) => {
                if (containsPii) {
                    return;
                }
                switch (level) {
                    case LogLevel.Error:
                        console.error(message);
                        return;
                    case LogLevel.Info:
                        console.info(message);
                        return;
                    case LogLevel.Verbose:
                        console.debug(message);
                        return;
                    case LogLevel.Warning:
                        console.warn(message);
                        return;
                    default:
                        return;
                }
            },
        },
    },
};

/**
 * Scopes you add here will be prompted for user consent during sign-in.
 * By default, MSAL.js will add OIDC scopes (openid, profile, email) to any login request.
 * For more information about OIDC scopes, visit: 
 * https://docs.microsoft.com/azure/active-directory/develop/v2-permissions-and-consent#openid-connect-scopes
 */
export const loginRequest = {
    scopes: [],
};

/**
 * An optional silentRequest object can be used to achieve silent SSO
 * between applications by providing a "login_hint" property.
 */
// export const silentRequest = {
//     scopes: ["openid", "profile"],
//     loginHint: "example@domain.net"
// };

Replace the following values with the values from the Azure portal:
- Find the Enter_the_Application_Id_Here value and replace it with the Application ID (clientId) of the app you registered in the Microsoft Entra admin center.
- In Authority, find Enter_the_Tenant_Subdomain_Here and replace it with the subdomain of your tenant. For example, if your tenant primary domain is contoso.onmicrosoft.com, use contoso. If you don't have your tenant name, learn how to read your tenant details.
Save the file.

Modify index.js to include the authentication provider

All parts of the app that require authentication must be wrapped in the MsalProvider component. You instantiate a PublicClientApplication then pass it to MsalProvider.

In the src folder, open index.js and replace the contents of the file with the following code snippet to use the msal packages and bootstrap styling:

import React from 'react';
import ReactDOM from 'react-dom/client';
import App from './App';
import { PublicClientApplication, EventType } from '@azure/msal-browser';
import { msalConfig } from './authConfig';

import 'bootstrap/dist/css/bootstrap.min.css';
import './styles/index.css';

/**
 * MSAL should be instantiated outside of the component tree to prevent it from being re-instantiated on re-renders.
 * For more, visit: https://github.com/AzureAD/microsoft-authentication-library-for-js/blob/dev/lib/msal-react/docs/getting-started.md
 */
const msalInstance = new PublicClientApplication(msalConfig);

// Default to using the first account if no account is active on page load
if (!msalInstance.getActiveAccount() && msalInstance.getAllAccounts().length > 0) {
    // Account selection logic is app dependent. Adjust as needed for different use cases.
    msalInstance.setActiveAccount(msalInstance.getActiveAccount()[0]);
}

// Listen for sign-in event and set active account
msalInstance.addEventCallback((event) => {
    if (event.eventType === EventType.LOGIN_SUCCESS && event.payload.account) {
        const account = event.payload.account;
        msalInstance.setActiveAccount(account);
    }
});

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(
    <App instance={msalInstance}/>
);

Next steps

Configure SPA for authentication