Add compression to build workflow example, closes #8

README.md

@@ -165,7 +165,7 @@ There exists a Python file in this repository, `_tools/create_entries.py`, which
 
 In case you do not want to install the entire Ruby/Jekyll toolchain on your machine you can make use of [GitHub Actions](https://github.com/features/actions), Github's continuous integration platform. This repository contains multiple example Github Action configuration files in the `_tools/` folder:
 
-- `build.yml`: automatically builds and minimizes the website upon adding a new tag starting with a `v` (e.g. `v2020.01.01`). It then attaches the generated website as an archive to a release for easy downloading.
+- `build.yml`: automatically builds and minimizes the website upon adding a new tag starting with a `v` (e.g. `v2020.01.01`). It then attaches the generated website as an archive to a release for easy downloading. Requires `purgecss.config.js` to be copied to the project's root too.
 - `test.yml`: automatically tries to build the website upon a new pull request. It can thus be used as status check before merging.
 - `schedule.yml`: automatically generates the schedule and content files when a new pull request contains a `schedule.json` file (see the _Automatic Import_subsection above). Thus, it allows quick updates of the site's content from [pretalx.com](https://pretalx.com/p/about/) exports.
 

_tools/build.yml

@@ -54,6 +54,33 @@ jobs:
         run: |
           minify --all --html-keep-document-tags --html-keep-end-tags -r -o _site/ _site/
 
+      - name: Setup Node
+        uses: actions/setup-node@v1
+        with:
+          node-version: '12'
+
+      - name: NPM Cache
+        uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
+
+      - name: Install PurgeCSS and Terser
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: |
+          npm install -g purgecss
+          npm install -g terser
+
+      - name: Compress CSS with PurgeCSS
+        run: |
+          purgecss --config purgecss.config.js
+
+      - name: Compress JavaScript with Terser
+        run: |
+          terser _site/assets/js/main.js --compress ecma=2015,top_retain=window.conference --mangle --comments false --output _site/assets/js/main.js
+
       - name: Package generated website
         run: |
           cd _site/

_tools/purgecss.config.js

@@ -0,0 +1,9 @@
+module.exports = {
+  content: ['_site/**/*.html','_site/assets/js/main.js'],
+  css: ['_site/assets/css/main.css'],
+  output: '_site/assets/css/main.min.css',
+  fontFace: true,
+  safelist: {
+    deep: [/^leaflet/]
+  }
+}