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Node.js v10.20.2-test20200417ef2df6986b Documentation
Usage#
node [options] [V8 options] [script.js | -e "script" | - ] [arguments]
Please see the Command Line Options document for information about different options and ways to run scripts with Node.js.
Example#
An example of a web server written with Node.js which responds with
'Hello, World!'
:
Commands displayed in this document are shown starting with $
or >
to replicate how they would appear in a user's terminal.
Do not include the $
and >
characters. They are there to
indicate the start of each command.
There are many tutorials and examples that follow this
convention: $
or >
for commands run as a regular user, and #
for commands that should be executed as an administrator.
Lines that don’t start with $
or >
character are typically showing
the output of the previous command.
Firstly, make sure to have downloaded and installed Node.js. See this guide for further install information.
Now, create an empty project folder called projects
, then navigate into it.
The project folder can be named based on the user's current project title, but
this example will use projects
as the project folder.
Linux and Mac:
$ mkdir ~/projects
$ cd ~/projects
Windows CMD:
> mkdir %USERPROFILE%\projects
> cd %USERPROFILE%\projects
Windows PowerShell:
> mkdir $env:USERPROFILE\projects
> cd $env:USERPROFILE\projects
Next, create a new source file in the projects
folder and call it hello-world.js
.
In Node.js it is considered good style to use
hyphens (-
) or underscores (_
) to separate
multiple words in filenames.
Open hello-world.js
in any preferred text editor and
paste in the following content:
const http = require('http');
const hostname = '127.0.0.1';
const port = 3000;
const server = http.createServer((req, res) => {
res.statusCode = 200;
res.setHeader('Content-Type', 'text/plain');
res.end('Hello, World!\n');
});
server.listen(port, hostname, () => {
console.log(`Server running at http://${hostname}:${port}/`);
});
Save the file, go back to the terminal window enter the following command:
$ node hello-world.js
An output like this should appear in the terminal to indicate Node.js server is running:
Server running at http://127.0.0.1:3000/
Now, open any preferred web browser and visit http://127.0.0.1:3000
.
If the browser displays the string Hello, World!
, that indicates
the server is working.
Many of the examples in the documentation can be run similarly.