Express.js res.locals Property - GeeksforGeeks

08 Jul, 2020
The res.locals property is an object that contains response local variables scoped to the request and because of this, it is only available to the view(s) rendered during that request/response cycle (if any).
Syntax:
res.locals
Parameter: No parameters.
Return Value: Object
Installation of express module:
You can visit the link to Install express module. You can install this package by using this command.npm install expressAfter installing the express module, you can check your express version in command prompt using the command.npm version expressAfter that, you can just create a folder and add a file for example, index.js. To run this file you need to run the following command.node index.js
You can visit the link to Install express module. You can install this package by using this command.npm install express
npm install express
After installing the express module, you can check your express version in command prompt using the command.npm version express
npm version express
After that, you can just create a folder and add a file for example, index.js. To run this file you need to run the following command.node index.js
node index.js
Example 1: Filename: index.js
var express = require('express');var app = express(); var PORT = 3000;  app.get('/', function (req, res) {    res.locals.user = 'GeeksforGeeks';    console.log(res.locals);    res.end();});  app.listen(PORT, function(err){    if (err) console.log(err);    console.log("Server listening on PORT", PORT);});
Steps to run the program:
The project structure will look like this:Make sure you have installed express module using the following command:npm install expressRun index.js file using below command:node index.jsOutput:Server listening on PORT 3000
Now open your browser and go to http://localhost:3000/, now you can see the following output on your console:Server listening on PORT 3000
[Object: null prototype] { user: 'GeeksforGeeks' }

The project structure will look like this:
Make sure you have installed express module using the following command:npm install express
npm install express
Run index.js file using below command:node index.jsOutput:Server listening on PORT 3000

node index.js
Output:
Server listening on PORT 3000

Now open your browser and go to http://localhost:3000/, now you can see the following output on your console:Server listening on PORT 3000
[Object: null prototype] { user: 'GeeksforGeeks' }

Server listening on PORT 3000
[Object: null prototype] { user: 'GeeksforGeeks' }

Example 2: Filename: index.js
var express = require('express');var app = express(); var PORT = 3000;  app.get('/', function (req, res) {      // Sending multiples locals    res.locals.name = 'Gourav';    res.locals.age = 13;    res.locals.gender = 'Male'          console.log(res.locals);    res.end();});  app.listen(PORT, function(err){    if (err) console.log(err);    console.log("Server listening on PORT", PORT);});
Run index.js file using below command:
node index.js
Output: Now open your browser and make GET request to http://localhost:3000, now you can see the following output on your console:
Server listening on PORT 3000
[Object: null prototype] { name: 'Gourav', age: 13, gender: 'Male' }

Reference: https://expressjs.com/en/4x/api.html#res.locals
Express.js
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