Add Cache Playwright Dependencies Across Workflows as a GitHub Actions TIL

Author: jbranchaud

Diff for: README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1310 TILs and counting..._
+_1311 TILs and counting..._
 
 ---
 
@@ -344,6 +344,7 @@ _1310 TILs and counting..._
 
 ### GitHub Actions
 
+- [Cache Playwright Dependencies Across Workflows](github-actions/cache-playwright-dependencies-across-workflows.md)
 - [Capture An Output Value For Use In A Later Step](github-actions/capture-an-output-value-for-use-in-a-later-step.md)
 - [Reference An Encrypted Secret In An Action](github-actions/reference-an-encrypted-secret-in-an-action.md)
 

Diff for: github-actions/cache-playwright-dependencies-across-workflows.md

@@ -0,0 +1,43 @@
+# Cache Playwright Dependencies Across Workflows
+
+With the help of `actions/cache@v3`, I can cache the dependency install and
+setup involved with using Playwright in GitHub Actions. That setup, in my
+experience, typically takes ~45s. When it is already cached, it is able to skip
+that step entirely greatly reducing the overall run time of the script.
+
+First, I need to define a cache (`playwright-cache`). Second, I need to only
+install the Playwright dependencies when that cache isn't available (`cache-hit
+!= 'true'`).
+
+Here is a striped down workflow demonstrating that.
+
+```yaml
+name: Playwright Script
+on:
+  workflow_dispatch:
+jobs:
+  Cached-Playwright-Script:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v3
+      - uses: actions/cache@v3
+        id: playwright-cache
+        with:
+          path: |
+            ~/.cache/ms-playwright
+          key: ${{ runner.os }}-playwright-${{ hashFiles('**/package-lock.json') }}
+      - name: Install dependencies
+        run: npm ci
+      - name: Install playwright deps
+        run: npx playwright install --with-deps chromium
+        if: steps.playwright-cache.outputs.cache-hit != 'true'
+      - run: node playwright-script.js
+```
+
+If I add the caching step and the cache-conditional `playwright install` steps
+to another workflow in this project, the cache will be available to both of
+them. That means they both benefit from the savings of that work having already
+been cached.
+
+[source](https://justin.poehnelt.com/posts/caching-playwright-in-github-actions/)