If we want to skip a middleware we can pass parameters to the middleware function and decide based on that parameter which middleware to call and which middleware to not call.
Prerequisite:
- express.js: To handle routing.
Setting up environment and execution:
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Step 1: Initialize node project
npm init
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Step 2: Install required modules
npm install express
Example:
index.js
const express = require("express");
// const database = require('./sqlConnection'); const app = express(); // Start server on port 5000 app.listen(5000, () => { console.log(`Server is up and running on 5000 ...`);
}); // define middleware 1 let middleware1 = (req, res, next) => { // decide a parameter
req.shouldRunMiddleware2 = false;
console.log("Middleware 1 is running !");
next();
} // define middleware 2 let middleware2 = (req, res, next) => { if(!req.shouldRunMiddleware2) {
console.log("Skipped middleware 2");
return next();
}
console.log("Middleware 2 is running !");
} // define middleware 3 let middleware3 = (req, res, next) => { console.log("Middleware 3 is running !");
} // create route for home page '/' app.get("/", middleware1, middleware2, middleware3);
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Output: Run the below command to start the server. After that go to http://localhost:5000 on browser to see output in console
node index.js
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In browser.
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Console: