Configure NODE_PATH to load plugin from GitHub workspace

.gitignore

@@ -1,2 +1,5 @@
 results/
-.lighthouseci/
+.lighthouseci/
+
+node_modules/.yarn-integrity
+node_modules/**/.DS_Store

README.md

@@ -386,6 +386,64 @@ against each of them. More details on this process are in the [Lighthouse CI doc
 
 </details>
 
+<details>
+ <summary>Use a Lighthouse plugin.</summary><br>
+
+#### main.yml
+
+```yml
+name: Lighthouse Audit
+on: push
+jobs:
+  lighthouse:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1 # checkout your own repo
+      - run: npm install # install your own dependencies
+      - name: Audit URLs using Lighthouse
+        uses: treosh/lighthouse-ci-action@v2
+        with:
+          urls: |
+            https://www.example.com/
+          configPath: ./lighthouserc.json
+      - name: Save results
+        uses: actions/upload-artifact@v1
+        with:
+          name: lighthouse-results
+          path: '.lighthouseci' # This will save the Lighthouse results as .json files
+```
+
+#### lighthouserc.json
+
+```json
+{
+  "ci": {
+    "collect": {
+      "settings": {
+        "plugins": [
+          "lighthouse-plugin-social-sharing"
+        ]
+      }
+    }
+  }
+}
+```
+
+#### package.json
+
+```json
+{
+  "name": "lighthouse-plugin-sample-project",
+  "devDependencies": {
+    "lighthouse-plugin-social-sharing": "0.0.1"
+  }
+}
+```
+
+[⚙️ See this example](https://github.com/connorjclark/lighthouse-plugin-sample-project)
+
+</details>
+
 Explore more workflows in [public examples](./.github/workflows).
 Submit a pull request with a new one if they don't cover your use case.
 

package.json

@@ -12,7 +12,8 @@
   },
   "dependencies": {
     "@actions/core": "^1.2.0",
-    "@lhci/cli": "0.3.4"
+    "@lhci/cli": "0.3.4",
+    "is-windows": "^1.0.2"
   },
   "devDependencies": {
     "@types/node": "10",

src/index.js

@@ -1,3 +1,15 @@
+// Append the node_modules of the github workspace and the node_modules of this action
+// to NODE_PATH. This supports lighthouse plugins - all the workspace needs to do is
+// `npm install` the plugin. The copy of lighthouse within this action will be used.
+
+const nodePathDelim = require('is-windows')() ? ';' : ':';
+const nodePathParts = [
+  ...(process.env.NODE_PATH || '').split(nodePathDelim),
+  `${__dirname}/../node_modules`,
+  `${process.env.GITHUB_WORKSPACE}/node_modules`,
+];
+process.env.NODE_PATH = nodePathParts.join(nodePathDelim);
+
 const core = require('@actions/core')
 const childProcess = require('child_process')
 const lhciCliPath = require.resolve('@lhci/cli/src/cli.js')

yarn.lock

@@ -1012,6 +1012,11 @@ is-typedarray@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/is-typedarray/-/is-typedarray-1.0.0.tgz#e479c80858df0c1b11ddda6940f96011fcda4a9a"
 
+is-windows@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/is-windows/-/is-windows-1.0.2.tgz#d1850eb9791ecd18e6182ce12a30f396634bb19d"
+  integrity sha512-eXK1UInq2bPmjyX6e3VHIzMLobc4J94i4AWn+Hpq3OU5KkrRC96OAcR3PRJ/pGu6m8TRnBHP9dkXQVsT/COVIA==
+
 is-wsl@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/is-wsl/-/is-wsl-1.1.0.tgz#1f16e4aa22b04d1336b66188a66af3c600c3a66d"