Add option to make npm install optional

README.md

@@ -69,6 +69,7 @@ You provide configuration properties within your workflow by using the `with` pr
 | useEslintrc | boolean | true | false | Use eslintrc? |
 | useEslintIgnore | boolean | true | false | Use eslintignore? |
 | fix | boolean | false | false | Commit fixes when possible (UNFINISHED) |
+| npmInstall | boolean | true | false | Runs `npm install` for you |
 
 > The official settings can always be seen by viewing the [`action.yml`](https://github.com/bradennapier/eslint-plus-action/blob/master/action.yml) schema for the action.
 
@@ -126,6 +127,24 @@ jobs:
         reportIgnoredFiles: true
 ```
 
+### With a manual `npm install` step
+
+```yml
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: npm ci
+      - name: Run a build step
+        run: npm run build
+      - uses: bradennapier/eslint-plus-action@v2
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          npmInstall: false
+```
+
 ## More Previews
 
 <p align="center">

action.yml

@@ -53,8 +53,13 @@ inputs:
   fix:
     description: 'Run with --fix? Defaults to false'
     required: false
+  npmInstall:
+    description: 'Run npm install (or yarn) for you. If you do not use this option, do the npm install step yourself, before running this action. Defaults to true'
+    required: false
+    default: true
 runs:
   using: docker
   image: Dockerfile
   args:
     - "${{ inputs.github-token }}"
+    - "${{ inputs.npmInstall }}"

entrypoint.sh

@@ -21,9 +21,11 @@ set -e
 
 echo "First Install";
 ls -alh
-echo "Install Yarn"
-[ -f yarn.lock ] && yarn install --frozen-lockfile --prefer-offline
-[ -f package-lock.json ] && npm install
+if [ "$2" = true ] ; then
+    echo "Install Yarn"
+    [ -f yarn.lock ] && yarn install --frozen-lockfile --prefer-offline
+    [ -f package-lock.json ] && npm install
+fi
 
 pushd /action
 echo "Yarn Action Install"