Getting error while using Express with Node.js - node.js

Question

I wrote a small program using npm express. while I am running the program i am getting error like below.(I am new to node.js)
module.js:340
throw err;
^
Error: Cannot find module 'express'
at Function.Module._resolveFilename (module.js:338:15)
at Function.Module._load (module.js:280:25)
at Module.require (module.js:362:17)
at require (module.js:378:17)
at Object.<anonymous> (C:\Users\node\node_modules\app.js:1:77)
at Module._compile (module.js:449:26)
at Object.Module._extensions..js (module.js:467:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Module.runMain (module.js:492:10)

Answer 1

Inside your app you obviously require the express module, probably like this:
var express = require('express');
For this line to work you need to install Express into the local context of your application. To do so run
$ npm install express
inside your application's folder. This will (if it does not yet exist) create a folder node_modules where all your dependencies go.
Additionally, I'd suggest that you put Express into your package.json inside the dependencies block, such as:
"dependencies": {
"express": "3.1.0"
}
Of course, you can adjust the version number to whatever version you use. Once you've done this for all of your dependencies, you can install them at once by simply running
$ npm install
That should fix it.
PS: It does not matter for this scenario whether you installed Express globally or not. A global installation is only good for having the express bootstrapper available system-wide. The require function always only searches within the local application context.