= UI Development Prerequisites
ifndef::env-site,env-github[]
include::_attributes.adoc[]
endif::[]
// Settings:
:idprefix:
:idseparator: -
// URIs:
:uri-nvm: https://github.com/creationix/nvm
:uri-node: https://nodejs.org
:uri-gulp: http://gulpjs.com
:uri-yarn: https://yarnpkg.com
:uri-git: https://git-scm.com
:uri-git-dl: {uri-git}/downloads
:uri-nvm-install: {uri-nvm}#installation
// These prerequisite instructions are less detailed than Antora's prerequisite instructions, I don't know if this is a concern or not.

An Antora UI project is based on tools built atop Node.js (aka Node), namely:

* {uri-node}[Node] (command: `node`)
 ** {uri-nvm}[nvm] (optional, but strongly recommended)
* {uri-gulp}[Gulp] (command: `gulp`)
* {uri-yarn}[Yarn] (command: `yarn`)

You also need {uri-git}[git] (command: `git`) to pull down the project and push updates to it.

== git

First, make sure you have git installed.

 $ git --version

If not, {uri-git-dl}[download and install] the git package for your system.

== Node 8

Next, make sure that you have Node 8 installed.
While you can install Node from the official packages, we strongly recommend that you use {uri-nvm}[nvm] (Node Version Manager) to install and manage Node.
Follow the {uri-nvm-install}[nvm installation instructions] to set up nvm on your machine.

Once you've installed nvm, open a new terminal and install Node 8 using the following command:

 $ nvm install 8

You can switch to this version of Node at any time using the following command:

 $ nvm use 8

To make Node 8 the default in new terminals, type:

 $ nvm alias default 8

Now that you have Node 8 installed, you can proceed with installing the Gulp CLI and Yarn.

== Gulp CLI

Next, you'll need the Gulp CLI (aka wrapper).
This package provides the `gulp` command which executes the version of Gulp declared by the project.
You should install the Gulp CLI globally (which resolves to a location in your user directory if you're using nvm) using the following command:

 $ npm install -g gulp-cli

== Yarn

Finally, you'll need Yarn, which is the preferred package manager for the Node ecosystem.
You'll need to use the `npm` command to install Yarn, though this is the last time you'll use the `npm` command.
You should install Yarn globally (which resolves to a location in your user directory if you're using nvm) using the following command:

 $ npm install -g yarn

Verify Yarn is installed by checking the version:

 $ yarn --version

Now that you have Node, Yarn, and Gulp installed, you're ready to set up the project.