anchor.diff:  
   To build Asciidoctor.js, simply run the npm `build` script from the root of the project:
   
  - $ npm run build
  + $ npm run build --prefix packages/core
   
   NOTE: The build task will make some minor code changes on Asciidoctor Ruby code.
   As you may know, {uri-mdn-string}[strings are immutable] in JavaScript, so we need to replace the `gsub!` and `sub!` methods.
   These changes are made at build time to keep the Ruby code as fast as possible.
   
  -This command produces a file named `asciidoctor.js` in the [path]_build_ directory.
  -This file contains everything you need to use Asciidoctor in a JavaScript environment.
  +This command produces one JavaScript file per environment in the [path]_packages/core/build_ directory:
  +
  +- `asciidoctor-browser.js`
  +- `asciidoctor-node.js`
  +- `asciidoctor-graalvm.js`
  +
  +These files contain everything you need to use Asciidoctor in a JavaScript environment.
   
   You'll see this script in action when you run the examples, described next.
   
  
positive.code: 
   $ git clone https://github.com/asciidoctor/asciidoctor.js.git
  
  Next, switch to the _asciidoctor.js/packages/core_ directory and run npm's `install` command:
  
   $ cd asciidoctor.js/packages/core
     npm i
  
  You're now ready to build Asciidoctor.js.
  
  TIP: Opal.js, the Ruby runtime in JavaScript is available in `node_modules/opal-runtime/src/opal.js`
  
  == Building
  
  
negative.code: 
  To build the examples, simply run the npm `examples` task from the root of the project:
  
   $ npm run examples --prefix packages/core
  
  This command produces 3 examples in the [path]_packages/core/build/examples_ directory:
  
  * `userguide_test.html` demonstrate how a Ruby script can be compiled to JavaScript using the Opal Compiler and displayed within the browser as a normal HTML file.
  The Ruby script `userguide_test.rb` includes:
  ** a string that contains an AsciiDoc source document
  ** a call to the Asciidoctor API to render the content of that string to HTML
  ** an event listener that inserts the generated HTML into the page
  * `basic.html` demonstrates how to convert an inline AsciiDoc content and insert the result in the HTML page
  * `asciidoctor_example.html` demonstrates how to convert a file using the include directive and insert the result in the HTML page
  
  In order to visualize the result, a local http server must be started within the root of this project otherwise you will have a cross origin issue which prevents to load some resources and render the HTML.
  For this purpose, you can run the following command to start a HTTP server locally: `npm run server --prefix packages/core`
  
  Once the server is listening, you can point your browser at:
  
  