Hello World in Saxon JS 2 on Node.js

This project contains (almost) the simplest possible “hello world” example using Saxon JS 2 in Node.js.

Prerequisites

This goal of this project is to show you how to get a simple Saxon JS project up and running in Node.js. You have to install Node.js yourself.

TL;DR

Run npm install to download and install the Node.js packages.

Run npm run start:dev to start the web application. This will be on port 3002 by default. If you want to run it on a different port, edit .env.

Point your web browser at http://localhost:3002/ and http://localhost:3002/json.

What is it?

This application is a very simple node application that displays “Hello, World” or displays the key/value pairs from a JSON map passed to it.

That’s pretty dull to look at, but the cool part is what it does behind the scenes.

What does it do?

When you issue a GET for “/”, the main stylesheet is run and it returns an HTML page with some static text.

When you issue a GET for “/json”, the main stylesheet is passed a JSON map. The map is hard coded into index.js, but in real life it might have come from another web service or from some other part of your application. In this case, the stylesheet returns a page that shows the key/value pairs in the map.

Unlike the helloWorldJS example, this version runs the XSLT processor in Node.js, on the server, not in your browser. Of course, there’s nothing to prevent you from processing the output of this process with another XSLT process in the browser!

How does it work?

There are a few moving pieces. They aren’t all strictly part of the Saxon JS transformation, but they are intended to give you a sense of how the pieces might fit together in a more realistic application.

The sources

• index.js is an Express web application that supports two endpoints, “/” and “/json”. Both run the XSLT stylesheet to return the results.
• main.sef.json is the compiled stylesheet. The XSLT source is in xslt/main.xsl.
• .env, package.json, and package-lock.json are just Node.js furniture.

The compiler

This project comes with a compiled version of the stylesheet. If you make changes to it, you can compile it with xslt-3 as follows:

$ node node_modules/xslt3/xslt3.js -t -xsl:xslt/main.xsl -export:main.sef.json -nogo "-ns:##html5"

You can also compile it with Saxon EE, if you prefer.

Next steps

Once you have it running, you can start playing around. Make changes to the stylesheet, recompile it, and see what happens!