Found 70 Questions for Express JS

Express.js – app.param() Method

Mayank Agarwal
Updated on 30-Sep-2021 13:51:22
The app.param() method is basically used for adding the callback triggers to the route parameters, where name represents the name of the parameter or an array of them and callback represents the callback function.Syntaxapp.param([name], callback)Parametersname − Represents the name of the parameter or array of parameters as required.callback − Represents the callback function. The parameters of the callback function include the request object, the response object, the next middleware, the value of the parameter, and the name of the parameter in the same order.ExampleCreate a file with the name "appParam.js" and copy the following code snippet. After creating the file, ... Read More

Express.js – app.mountpath Property

Mayank Agarwal
Updated on 30-Sep-2021 13:45:15
The app.mountpath property contains those path patterns on which a sub-app was mounted. A sub-app can be defined as an instance of Express that may be used for handling the request to a route.This property is similar to the baseUrl property of the req object; the only difference is that req.baseUrl returns the matched URL path instead of the matched patterns.Syntaxapp.mountpathExample 1Create a file "appMountpath.js" and copy the following code snippet. After creating the file, use the command "node appMountpath" to run this code.// app.mountpath code Demo Example // Importing the express module var express = require('express'); // ... Read More

Express.js – app.locals Property

Mayank Agarwal
Updated on 30-Sep-2021 13:35:14
The app.locals object defines the properties that are local variables inside an application. Once the value of app.locals property is set, it persists throughout the life of the application. The res.locals property is valid only for the lifetime of the request.Syntaxapp.localsExample 1Create a file "appLocals.js" and copy the following code snippet. After creating the file, use the command "node appLocals.js" to run this code.// app.locals code Demo Example // Importing the express module var express = require('express'); // Initializing the express and port number var app = express(); // Setting the below email throught out the application ... Read More

Express.js – app.listen() Method

Mayank Agarwal
Updated on 30-Sep-2021 13:29:13
The app.listen() method binds itself with the specified host and port to bind and listen for any connections. If the port is not defined or 0, an arbitrary unused port will be assigned by the operating system that is mainly used for automated tasks like testing, etc.The app object returned by express() is a JavaScript function, that is passed to Node’s HTTP servers as a callback which handles the requests. This makes the application to provide both HTTP and HTTPS versions of the same app with the same code base, as the app does not inherit from these.Syntaxapp.listen([port], [host], [backlog], ... Read More

Express.js – app.engine() Method

Mayank Agarwal
Updated on 30-Sep-2021 12:37:41
The app.engine() method is used for registering the given template engine callback as "ext". The require() method needs the engine based on the function by default.Use the following methods for engines that do not provide the extensions (or want to map different extensions) or express out of the box.app.engine('html', require('ejs').renderFile)Syntaxapp.engine(ext, callback)Example 1Create a file with the name "appEngine.js" and copy the following code snippet. After creating the file, use the command "node appEngine.js" to run this code.// app.engine() Method Demo Example // Importing the express module const express = require('express'); // Initializing the express and port number var ... Read More

Express.js – app.enable() Method

Mayank Agarwal
Updated on 30-Sep-2021 12:16:52
The app.enable() function sets the Boolean setting ‘name’ to ‘true’, where name defines one of the properties from the app settings table. Using the app.set('foo', true) for a Boolean property is same as calling the app.enable('foo') function.Syntaxapp.enable(name)Example 1Create a file with the name "appEnable.js" and copy the following code snippet. After creating the file, use the command "node appEnable.js" to run this code.// app.enable() Method Demo Example // Importing the express module const express = require('express'); // Initializing the express and port number var app = express(); // Initializing the router from express var router = express.Router(); ... Read More

Express.js – app.disable() Method

Mayank Agarwal
Updated on 30-Sep-2021 12:13:31
The app.disable() method disables the setting name passed in the function. This method sets the setting name to False. We can perform the same function by using the app.set() method too, by passing its value as False.Syntaxapp.disable(name)Example 1Create a file with the name "appDisable.js" and copy the following code snippet. After creating the file, use the command "node appDisable.js" to run this code.// app.disable() Method Demo Example // Importing the express module const express = require('express'); // Initializing the express and port number var app = express(); // Initializing the router from express var router = express.Router(); ... Read More

Express.js – app.delete() Method

Mayank Agarwal
Updated on 30-Sep-2021 12:09:47
The app.delete() method routes all the HTTP DELETE requests to the specified path with the specified callback functions.Syntaxapp.delete(path, callback, [callback])Parameterspath − This is the path for which the middleware function is invoked. A path can be a string, path pattern, a regular expression, or an array of all these.callback − These are the middleware functions or a series of middleware functions that act like a middleware except that these callbacks can invoke next (route).Example 1Create a file "appDelete.js" and copy the following code snippet. After creating the file, use the command "node appDelete.js" to run this code.// app.delete() Method Demo ... Read More

Express.js – app.all() Method

Mayank Agarwal
Updated on 30-Sep-2021 12:01:14
The app.all() method can be used for all types of routings of a HTTP request, i.e., for POST, GET, PUT, DELETE, etc., requests that are made to any specific route. It can map app types of requests with the only condition that the route should match.Syntaxapp.path(path, callback, [callback])Parameterspath − This is the path for which the middleware function is invoked. A path can be a string, path pattern, a regular expression or an array of all these.callback − These are the middleware functions or a series of middleware functions that act like a middleware except that these callbacks can invoke ... Read More

Filtering paths and creating html page in express.js

Shyam Hande
Updated on 13-May-2020 13:32:50
We added express router to handle routes. One single router file handles multiple routes.Adding a path for router in App.js −const http = require('http'); const express = require('express'); const bodyParser = require('body-parser'); const route = require('./routes'); const app = express(); app.use(bodyParser.urlencoded({extended: false})); app.use('/test', route); app.use((req, res, next)=>{    res.status(404).send(' Page not found '); }); const server = http.createServer(app); server.listen(3000);In router middleware we used path −/p>app.use('/test', route);Router will handle all paths starting with /test e.g. /test/add-usernameWe have to change action in form in routes.js file −router.get('/add-username', (req, res, next)=>{    res.send('     Send '); });Routes.js file −const express ... Read More
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