Migrate to ESM with rollup and Node 24

.gitattributes

@@ -1 +1,2 @@
-dist/** -diff linguist-generated=true 
+* text=auto eol=lf
+dist/** -diff linguist-generated=true

.github/workflows/check-dist.yml

@@ -0,0 +1,48 @@
+name: Check Transpiled JavaScript
+
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+
+permissions:
+  contents: read
+
+jobs:
+  check-dist:
+    name: Check dist/
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version-file: .node-version
+          cache: npm
+
+      - name: Install Dependencies
+        run: npm ci
+
+      - name: Build dist/ Directory
+        run: npm run package
+
+      - name: Compare Directories
+        id: diff
+        run: |
+          if [ "$(git diff --ignore-space-at-eol --text dist/ | wc -l)" -gt "0" ]; then
+            echo "Detected uncommitted changes after build. See status below:"
+            git diff --ignore-space-at-eol --text dist/
+            exit 1
+          fi
+
+      - if: ${{ failure() && steps.diff.conclusion == 'failure' }}
+        name: Upload Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: Continuous Integration
+
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+
+permissions:
+  contents: read
+
+jobs:
+  typescript:
+    name: TypeScript Checks
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version-file: .node-version
+          cache: npm
+
+      - name: Install Dependencies
+        run: npm ci
+
+      - name: Check Format
+        run: npm run format:check
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Test
+        run: npm run ci-test

.github/workflows/test.yml

@@ -1,33 +1,33 @@
-name: 'nix-shell-action-test'
+name: "nix-shell-action-test"
 on: # rebuild any PRs and main branch changes
   pull_request:
   push:
     branches:
       - main
       - support-devshell
-      - 'releases/*'
+      - "releases/*"
 
 jobs:
   build: # make sure build/ci work properly
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
-          node-version: 20
+          node-version-file: .node-version
       - run: |
           npm install
       - run: |
           npm run all
   test-latest-nix:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
@@ -57,7 +57,7 @@ jobs:
   test-legacy-nix:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
@@ -89,7 +89,7 @@ jobs:
   test-flakes:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
@@ -112,7 +112,7 @@ jobs:
   test-local-flake-in-working-directory:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
@@ -131,7 +131,7 @@ jobs:
   test-flakes-from-devshell:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
@@ -148,7 +148,7 @@ jobs:
   test-flakes-from-devshell-with-custom-shell:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:
@@ -166,7 +166,7 @@ jobs:
   test-flakes-from-devshell-in-working-directory:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Nix
         uses: cachix/install-nix-action@v30
         with:

.node-version

@@ -1 +1 @@
-21.7.2
+24.4.0

.prettierignore

@@ -1,3 +1,5 @@
 dist/
 node_modules/
 coverage/
+.DS_Store
+.licenses/

README.md

@@ -10,16 +10,16 @@ on Linux and macOS.
 Create `.github/workflows/test.yml` in your repo with the following contents:
 
 ```yaml
-name: 'Test'
+name: "Test"
 on:
   pull_request:
   push:
 jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: cachix/install-nix-action@v18
+      - uses: actions/checkout@v6
+      - uses: cachix/install-nix-action@v30
         with:
           nix_path: nixpkgs=channel:nixos-unstable
       - uses: workflow/nix-shell-action@v3
@@ -57,17 +57,17 @@ flakes to be available in your script. This can be used for both local flakes in
 a `flake.nix` in your repo, as well as external flakes.
 
 ```yaml
-name: 'Test'
+name: "Test"
 on:
   pull_request:
   push:
 jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - name: Install Nix
-        uses: cachix/install-nix-action@v18
+        uses: cachix/install-nix-action@v30
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -88,17 +88,17 @@ Instead of specifying `flakes`, you can also tell this action to re-use the
 make these available to the script:
 
 ```yaml
-name: 'Test with Flakes from DevShell'
+name: "Test with Flakes from DevShell"
 on:
   pull_request:
   push:
 jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - name: Install Nix
-        uses: cachix/install-nix-action@v18
+        uses: cachix/install-nix-action@v30
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -142,16 +142,16 @@ jobs:
 # FAQ: Passing a Github Token against Rate Limits
 
 ```yaml
-name: 'Test'
+name: "Test"
 on:
   pull_request:
   push:
 jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: cachix/install-nix-action@v18
+      - uses: actions/checkout@v6
+      - uses: cachix/install-nix-action@v30
         with:
           nix_path: nixpkgs=channel:nixos-unstable
           extra_nix_config: |
@@ -173,6 +173,9 @@ See
 
 # Hacking
 
+Built with [Rollup](https://rollupjs.org/) (ESM) and TypeScript. Run
+`npm run package` to rebuild `dist/`.
+
 See https://github.com/actions/typescript-action
 
 [nix]: https://nixos.org/nix/

action.yml

@@ -1,45 +1,44 @@
-name: 'Nix Shell'
-description:
-  'Run any command you like in a deterministic nix shell on Linux and macOS'
-author: '@workflow'
+name: "Nix Shell"
+description: "Run any command you like in a deterministic nix shell on Linux and macOS"
+author: "@workflow"
 inputs:
   interpreter:
     required: false
-    description: 'Interpreter to use in the nix shell shebang'
-    default: 'bash'
+    description: "Interpreter to use in the nix shell shebang"
+    default: "bash"
   packages:
     required: false
     description:
       'Comma-separated list of packages to pre-install in your shell. Defaults
       to simply "bash". Cannot be used together with the flakes option'
-    default: 'bash'
+    default: "bash"
   flakes:
     required: false
     description:
-      'Comma-separated list of fully qualified flakes to pre-install in your
+      "Comma-separated list of fully qualified flakes to pre-install in your
       shell. Use either packages or flakes. Cannot be used together with the
-      packages option'
-    default: ''
+      packages option"
+    default: ""
   flakes-from-devshell:
     required: false
-    description: 'If set to true, uses devShell instead.'
+    description: "If set to true, uses devShell instead."
     default: false
   custom-devshell:
     required: false
-    description: 'If set, uses a customly named devShell from the current flake'
-    default: ''
+    description: "If set, uses a customly named devShell from the current flake"
+    default: ""
   script:
     required: true
-    description: 'The actual script to execute in the shell'
+    description: "The actual script to execute in the shell"
   working-directory:
     required: false
     description:
-      'Execute the script inside the specified working directory instead of the
-      repository root. Example: path/to/dir'
+      "Execute the script inside the specified working directory instead of the
+      repository root. Example: path/to/dir"
 
 branding:
-  color: 'blue'
-  icon: 'chevron-right'
+  color: "blue"
+  icon: "chevron-right"
 runs:
-  using: 'node20'
-  main: 'dist/index.js'
+  using: "node24"
+  main: "dist/index.js"