Learn what the 'next' function in middleware does and how it is used in Express apps with examples in JavaScript.
What is the next function in Middleware?
The next
function in middleware is a callback function that tells the Express app to move on to the next middleware function in the current middleware stack. It is typically used to perform some action or execute some code and then pass control to the next middleware function. Here's an example in JavaScript:
javascript Copy code
app.use(function (req, res, next) {
console.log('Time:', Date.now());
next();
});
In the above code snippet, the next()
function is called after logging the current time, indicating that the app should move on to the next middleware function in the stack.
What is Node.js, its features, and how it works
Node.js is an open-source, cross-platform runtime environment that allows developers to run JavaScript code outside of a web browser.
Some of the features of Node.js include:
Node.js works by running JavaScript code outside of the web browser environment, instead using the V8 JavaScript engine to execute the code. It reads the JavaScript file, executes the code, and returns the result.
Here's an example of a basic HTTP server in Node.js:
javascript Copy code
const http = require('http');
const hostname = '127.0.0.1';
const port = 3000;
const server = http.createServer((req, res) => {
res.statusCode = 200;
res.setHeader('Content-Type', 'text/plain');
res.end('Hello, world!');
});
server.listen(port, hostname, () => {
console.log(`Server running at http://${hostname}:${port}/`);
});
This code creates an HTTP server that listens for incoming requests on port 3000. When a request is received, it responds with a plain text message of "Hello, world!".
You can learn more about Node.js on their official website: https://nodejs.org/en/about/
How do i implement an oauth github social login feature on my express node js web app?
You can implement an OAuth Github social login for a node.js/express app by following the steps below:
Example code for step 4 – Initializing the OAuth strategy:
javascript Copy code
passport.use(
new GithubStrategy({
clientID: process.env.GITHUB_CLIENT_ID,
clientSecret: process.env.GITHUB_CLIENT_SECRET,
callbackURL: "http://localhost:3000/auth/github/callback"
},
function(accessToken, refreshToken, profile, done) {
// find, create or authenticate the user with their github credentials.
}
));
What is Node.js
Node.js is an open-source, cross-platform JavaScript run-time environment that executes JavaScript code outside of a browser. Node.js lets developers use JavaScript to write command line tools and for server-side scripting running scripts server-side to produce dynamic web page content before the page is sent to the user's web browser. Node.js is used for application development and automating tasks.
What are the most common node js interview questions
Common node.js interview questions include:
See this Stack Overflow answer for an in-depth look into Node.js interview questions.