switch to ESM and update config/test wiring

.prettierrc.json

@@ -6,6 +6,5 @@
   "singleQuote": true,
   "trailingComma": "none",
   "bracketSpacing": false,
-  "arrowParens": "avoid",
-  "parser": "typescript"
+  "arrowParens": "avoid"
 }

__tests__/context.test.ts

@@ -1,23 +1,23 @@
-import {beforeEach, describe, expect, jest, test} from '@jest/globals';
+import {beforeEach, describe, expect, vi, test} from 'vitest';
 import * as fs from 'fs';
+import * as os from 'os';
 import * as path from 'path';
 
-import {Context} from '@docker/actions-toolkit/lib/context';
+import {Context} from '@docker/actions-toolkit/lib/context.js';
 
-import * as context from '../src/context';
+import * as context from '../src/context.js';
 
-// prettier-ignore
-const tmpDir = path.join(process.env.TEMP || '/tmp', 'setup-compose-jest');
-const tmpName = path.join(tmpDir, '.tmpname-jest');
+const tmpDir = fs.mkdtempSync(path.join(process.env.TEMP || os.tmpdir(), 'context-'));
+const tmpName = path.join(tmpDir, '.tmpname-vi');
 
-jest.spyOn(Context, 'tmpDir').mockImplementation((): string => {
+vi.spyOn(Context, 'tmpDir').mockImplementation((): string => {
   if (!fs.existsSync(tmpDir)) {
     fs.mkdirSync(tmpDir, {recursive: true});
   }
   return tmpDir;
 });
 
-jest.spyOn(Context, 'tmpName').mockImplementation((): string => {
+vi.spyOn(Context, 'tmpName').mockImplementation((): string => {
   return tmpName;
 });
 

__tests__/setup.unit.ts

@@ -0,0 +1,12 @@
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+
+const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'docker-actions-toolkit-'));
+
+process.env = Object.assign({}, process.env, {
+  TEMP: tmpDir,
+  GITHUB_REPOSITORY: 'docker/setup-compose-action',
+  RUNNER_TEMP: path.join(tmpDir, 'runner-temp'),
+  RUNNER_TOOL_CACHE: path.join(tmpDir, 'runner-tool-cache')
+});

dev.Dockerfile

@@ -74,7 +74,7 @@ FROM deps AS test
 RUN --mount=type=bind,target=.,rw \
   --mount=type=cache,target=/src/.yarn/cache \
   --mount=type=cache,target=/src/node_modules \
-  yarn run test --coverage --coverageDirectory=/tmp/coverage
+  yarn run test --coverage --coverage.reportsDirectory=/tmp/coverage
 
 FROM scratch AS test-coverage
 COPY --from=test /tmp/coverage /

eslint.config.mjs

@@ -0,0 +1,52 @@
+import {defineConfig} from 'eslint/config';
+import js from '@eslint/js';
+import tseslint from '@typescript-eslint/eslint-plugin';
+import vitest from '@vitest/eslint-plugin';
+import globals from 'globals';
+import eslintConfigPrettier from 'eslint-config-prettier/flat';
+import eslintPluginPrettier from 'eslint-plugin-prettier';
+
+export default defineConfig([
+  {
+    ignores: ['.yarn/**/*', 'coverage/**/*', 'dist/**/*']
+  },
+  js.configs.recommended,
+  ...tseslint.configs['flat/recommended'],
+  eslintConfigPrettier,
+  {
+    languageOptions: {
+      globals: {
+        ...globals.node
+      }
+    }
+  },
+  {
+    files: ['__tests__/**'],
+    ...vitest.configs.recommended,
+    languageOptions: {
+      globals: {
+        ...globals.node,
+        ...vitest.environments.env.globals
+      }
+    },
+    rules: {
+      ...vitest.configs.recommended.rules,
+      'vitest/no-conditional-expect': 'error',
+      'vitest/no-disabled-tests': 0
+    }
+  },
+  {
+    plugins: {
+      prettier: eslintPluginPrettier
+    },
+    rules: {
+      'prettier/prettier': 'error',
+      '@typescript-eslint/no-require-imports': [
+        'error',
+        {
+          allowAsImport: true
+        }
+      ]
+    }
+  }
+]);

package.json

@@ -1,16 +1,13 @@
 {
   "name": "docker-setup-compose",
   "description": "Set up Docker Compose",
+  "type": "module",
   "main": "src/main.ts",
   "scripts": {
     "build": "ncc build --source-map --minify --license licenses.txt",
-    "lint": "yarn run prettier && yarn run eslint",
-    "format": "yarn run prettier:fix && yarn run eslint:fix",
-    "eslint": "eslint --max-warnings=0 .",
-    "eslint:fix": "eslint --fix .",
-    "prettier": "prettier --check \"./**/*.ts\"",
-    "prettier:fix": "prettier --write \"./**/*.ts\"",
-    "test": "jest"
+    "lint": "eslint --max-warnings=0 .",
+    "format": "eslint --fix .",
+    "test": "vitest run"
   },
   "repository": {
     "type": "git",
@@ -29,21 +26,19 @@
     "@docker/actions-toolkit": "^0.62.1"
   },
   "devDependencies": {
-    "@eslint/compat": "^2.0.0",
-    "@eslint/eslintrc": "^3.3.3",
-    "@eslint/js": "^9.39.2",
-    "@types/node": "^20.19.27",
-    "@typescript-eslint/eslint-plugin": "^8.50.0",
-    "@typescript-eslint/parser": "^8.50.0",
+    "@eslint/js": "^9.39.3",
+    "@types/node": "^20.19.35",
+    "@typescript-eslint/eslint-plugin": "^8.56.1",
+    "@typescript-eslint/parser": "^8.56.1",
     "@vercel/ncc": "^0.38.4",
-    "eslint": "^9.39.2",
+    "@vitest/coverage-v8": "^4.0.18",
+    "@vitest/eslint-plugin": "^1.6.9",
+    "eslint": "^9.39.3",
     "eslint-config-prettier": "^10.1.8",
-    "eslint-plugin-jest": "^29.5.0",
-    "eslint-plugin-prettier": "^5.5.4",
-    "jest": "^30.2.0",
-    "prettier": "^3.7.4",
-    "ts-jest": "^29.4.6",
-    "ts-node": "^10.9.2",
-    "typescript": "^5.9.3"
+    "eslint-plugin-prettier": "^5.5.5",
+    "globals": "^17.3.0",
+    "prettier": "^3.8.1",
+    "typescript": "^5.9.3",
+    "vitest": "^4.0.18"
   }
 }

src/main.ts

@@ -1,10 +1,10 @@
 import * as core from '@actions/core';
 import * as actionsToolkit from '@docker/actions-toolkit';
 
-import {Docker} from '@docker/actions-toolkit/lib/docker/docker';
-import {Toolkit} from '@docker/actions-toolkit/lib/toolkit';
+import {Docker} from '@docker/actions-toolkit/lib/docker/docker.js';
+import {Toolkit} from '@docker/actions-toolkit/lib/toolkit.js';
 
-import * as context from './context';
+import * as context from './context.js';
 
 actionsToolkit.run(
   // main

tsconfig.json

@@ -1,8 +1,8 @@
 {
   "compilerOptions": {
+    "module": "nodenext",
+    "moduleResolution": "nodenext",
     "esModuleInterop": true,
-    "target": "es6",
-    "module": "commonjs",
     "strict": true,
     "newLine": "lf",
     "outDir": "./lib",
@@ -12,10 +12,7 @@
     "resolveJsonModule": true,
     "useUnknownInCatchVariables": false,
   },
-  "exclude": [
-    "./__tests__/**/*",
-    "./lib/**/*",
-    "node_modules",
-    "jest.config.ts"
+  "include": [
+    "src/**/*.ts"
   ]
 }

vitest.config.ts

@@ -0,0 +1,32 @@
+/**
+ * Copyright 2026 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {defineConfig} from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    clearMocks: true,
+    environment: 'node',
+    setupFiles: ['./__tests__/setup.unit.ts'],
+    include: ['**/*.test.ts'],
+    coverage: {
+      provider: 'v8',
+      reporter: ['clover'],
+      include: ['src/**/*.ts'],
+      exclude: ['src/**/main.ts', '__tests__/**', 'dist/**']
+    }
+  }
+});