Getting started with IBM SDK for Node.js - z/OS

To get started with IBM® SDK for Node.js - z/OS®, you can work with the Node edition of a "Hello World" program as an example. You can set up a simple web-server that responds to a GET request with the Hello World message through the following steps:

Under z/OS UNIX System Services (z/OS UNIX), create a separate HFS directory for the example "Hello World" program.
```
$>mkdir myapp
$>cd myapp
```
Set up the project by using the npm executable and filling out the requested details to populate a package.json file.
```
$>npm init
```
Node.js boasts an impressive 1 million (approximately) open source add-on modules, which can be used to develop applications. You can use the Express® web framework for the web-server example. To install the Express web framework, you can use the npm executable.
```
$>npm install express --save
```
After the Express web framework is installed, a node_modules directory is added under the myapp directory.

Write the following sample code into a server.js file.

/*Load express and instantiate, get the port number from command line*/
var express = require("express");
var server_instance = express();
var port = process.argv[2];

/*Respond to get requests to root dir*/
server_instance.get("/", function (req, res){ 
    res.send("Hello World\n");
})

/*Start webserver*/
server_instance.listen(port,function() {
    console.log("Listening on: " + port);
})

Start the web-server application from the z/OS UNIX prompt.
```
$>node server.js 1339
Listening on: 1339
```
Open a web browser or use the wget command to access the server through HTTP on port 1339. The Hello World message is returned.
```
$>wget https://<server address>:1339
cat index.html
Hello World
```

Through the previous steps, a simple web server is up and running.