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Skipping middleware in Express.js
You need to pass some parameters to skip the middleware in an Express application. On the basis of that parameter with logic in place, you can decide whether to execute a middleware or not
Syntax
There is no syntax defined. You can introduce a parameter and then check based upon that parameter whether to use the middleware or not.
Example
Create a file with the name "skipMiddleware.js" and copy the following code snippet. After creating the file, use the command "node skipMiddleware.js" to run this code as shown in the example below −
// app.set() Demo Example // Importing the express module var express = require('express'); // Initializing the express and port number var app = express(); var PORT = 3000; // Defining a middleware let middleware1 = (req, res, next) => { // Passing a middleware parameter req.shouldRunMiddleware2 = false; console.log("Middleware 1 is running !"); next(); } // Defining another middleware let middleware2 = (req, res, next) => { // SKipping middleware based in boolean value if(!req.shouldRunMiddleware2) { console.log("Skipped middleware 2"); return next(); } console.log("Middleware 2 is running !"); } // Defining another middleware let middleware3 = (req, res, next) => { console.log("Middleware 3 is running !"); } // Creating the route page for all the middlewares app.get("/", middleware1, middleware2, middleware3); // Listening on the port:3000 app.listen(PORT, function(err){ if (err) console.log(err); console.log("Server listening on PORT", PORT); });
Output
C:\home
ode>> node skipMiddleware.js Server listening on PORT 3000 Middleware 1 is running ! Skipped middleware 2 Middleware 3 is running !
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