feat(setup-js): auto detect package manager

Author: northword

setup-js/action.yml

@@ -19,31 +19,53 @@ inputs:
     default: true
 
   package-manager:
-    description: "Package manager to use. Examples: npm, yarn, pnpm."
-    default: pnpm
+    description: "Package manager to use. Examples: npm, yarn, pnpm. Leave empty to auto-detect."
+    default: ""
 
 runs:
   using: composite
   steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         persist-credentials: ${{ inputs.persist-credentials }}
         fetch-depth: "${{ inputs.fetch-all == 'true' && '0' || '1' }}"
         submodules: "${{ inputs.fetch-all == 'true' && 'recursive' || false }}"
 
+    - name: Auto detect package manager
+      id: detect
+      shell: bash
+      run: |
+        if [[ -n "${{ inputs.package-manager }}" ]]; then
+          echo "pm=${{ inputs.package-manager }}" >> $GITHUB_OUTPUT
+          exit 0
+        fi
+
+        if [[ -f "pnpm-lock.yaml" ]]; then
+          echo "pm=pnpm" >> $GITHUB_OUTPUT
+        elif [[ -f "yarn.lock" ]]; then
+          echo "pm=yarn" >> $GITHUB_OUTPUT
+        elif [[ -f "package-lock.json" ]]; then
+          echo "pm=npm" >> $GITHUB_OUTPUT
+        else
+          echo "No lock file found. Defaulting to pnpm."
+          echo "pm=pnpm" >> $GITHUB_OUTPUT
+        fi
+
     - name: Install pnpm
-      if: ${{ inputs.package-manager == 'pnpm' }}
+      if: ${{ steps.detect.outputs.pm == 'pnpm' }}
       uses: pnpm/action-setup@v4
 
     - name: Setup node
       uses: actions/setup-node@v6
       with:
         node-version: ${{ inputs.node-version }}
-        cache: ${{ inputs.package-manager }}
+        cache: ${{ steps.detect.outputs.pm }}
         registry-url: "https://registry.npmjs.org"
 
     - name: Install dependencies
+      if: ${{ inputs.auto-install == 'true' }}
       shell: bash
-      run: ${{ inputs.package-manager }} install
-      if: ${{ inputs.auto-install }}
+      run: |
+        echo "Using package manager: ${{ steps.detect.outputs.pm }}"
+        ${{ steps.detect.outputs.pm }} install