backend-google-login-ts/lib/index.js

A secure and lightweight TypeScript package for handling Google OAuth2 authentication in Node.js backend applications. Simplifies the process of integrating Google login with built-in TypeScript support and zero dependencies.

import https from 'https';
async function exchangeAuthCodeForToken(clientId, clientSecret, redirectUrl, authCode) {
    const tokenEndpoint = 'https://oauth2.googleapis.com/token';
    const postData = JSON.stringify({
        client_id: clientId,
        client_secret: clientSecret,
        redirect_uri: redirectUrl,
        grant_type: 'authorization_code',
        code: authCode,
    });
    const options = {
        hostname: 'oauth2.googleapis.com',
        path: '/token',
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'Content-Length': Buffer.byteLength(postData),
        },
    };
    return new Promise((resolve, reject) => {
        const req = https.request(options, (res) => {
            let data = '';
            res.on('data', (chunk) => {
                data += chunk;
            });
            res.on('end', () => {
                if (res.statusCode === 200) {
                    resolve(JSON.parse(data));
                }
                else {
                    reject(new Error(`Error: ${data}`));
                }
            });
        });
        req.on('error', (e) => {
            reject(e);
        });
        req.write(postData);
        req.end();
    });
}
async function getUserInfo(accessToken) {
    const userInfoEndpoint = 'https://www.googleapis.com/oauth2/v2/userinfo';
    const options = {
        hostname: 'www.googleapis.com',
        path: '/oauth2/v2/userinfo',
        method: 'GET',
        headers: {
            Authorization: `Bearer ${accessToken}`,
        },
    };
    return new Promise((resolve, reject) => {
        const req = https.request(options, (res) => {
            let data = '';
            res.on('data', (chunk) => {
                data += chunk;
            });
            res.on('end', () => {
                if (res.statusCode === 200) {
                    resolve(JSON.parse(data));
                }
                else {
                    reject(new Error(`Error fetching user info: ${data}`));
                }
            });
        });
        req.on('error', (e) => {
            reject(e);
        });
        req.end();
    });
}
// This function return userInfo or Error
export async function loginWithGoogle(options) {
    const { clientId, clientSecret, redirectUrl, authCode } = options;
    if (!clientId || !clientSecret || !redirectUrl || !authCode) {
        throw new Error('Missing required parameters');
    }
    try {
        // Get access token from google
        const tokenData = await exchangeAuthCodeForToken(clientId, clientSecret, redirectUrl, authCode);
        const accessToken = tokenData.access_token;
        // Use access token to get userInfo
        const userInfo = await getUserInfo(accessToken);
        return userInfo;
    }
    catch (error) {
        throw new Error(`Failed to login with Google: ${error.message}`);
    }
}