Migrate to ESM with esbuild, vitest (#227)

* Migrate to ESM, esbuild, vitest, and update actions/* to latest

- Update @actions/core to 3.x, @actions/exec to 3.x, @actions/io to 3.x
- Replace @vercel/ncc + babel with esbuild (build.mjs) targeting Node 20 ESM
- Replace jest/babel-jest/ts-jest with vitest and @vitest/coverage-v8
- Update tsconfig to NodeNext module resolution with strict mode
- Add explicit .js extensions to all relative imports (NodeNext requirement)
- Fix implicit any index signatures in parseCluster and parseMethod
- Migrate all test files from jest to vi.mock/vi.mocked APIs
- Fix ESM module spying limitations using vi.mock() at module level
- Fix env var test pollution in default.test.ts with afterEach cleanup

* remove build.mjs and update build script

* update pkg lock

* update pkg lock

babel.config.js

@@ -1,7 +0,0 @@
-// babel.config.js
-export default {
-   presets: [
-      '@babel/preset-env', // For handling ES modules
-      '@babel/preset-typescript' // For handling TypeScript
-   ]
-}

jest.config.js

@@ -1,28 +0,0 @@
-export default {
-   restoreMocks: true,
-   clearMocks: true,
-   resetMocks: true,
-   moduleFileExtensions: ['js', 'ts'],
-   testEnvironment: 'node',
-   testMatch: ['**/*.test.ts'],
-   transform: {
-      '^.+\\.ts$': 'ts-jest', // Use ts-jest for TypeScript files
-      '^.+\\.js$': 'babel-jest' // Transform TypeScript files
-   },
-   transformIgnorePatterns: [
-      '/node_modules/(?!@kubernetes/client-node)/' // Make sure to transform the Kubernetes client module
-   ],
-   moduleNameMapper: {
-      '^.+\\.css$': 'jest-transform-stub' // Handle CSS imports (if any)
-   },
-   extensionsToTreatAsEsm: ['.ts', '.tsx'], // Treat TypeScript files as ESM
-   verbose: true,
-   coverageThreshold: {
-      global: {
-         branches: 0,
-         functions: 40,
-         lines: 22,
-         statements: 22
-      }
-   }
-}

package.json

@@ -5,10 +5,10 @@
    "main": "lib/index.js",
    "type": "module",
    "scripts": {
-      "prebuild": "npm i @vercel/ncc",
+      "build": "tsc --noEmit && esbuild src/run.ts --bundle --platform=node --target=node20 --format=esm --outfile=lib/index.js --banner:js=\"import { createRequire } from 'module';const require = createRequire(import.meta.url);\"",
-      "build": "ncc build src/run.ts -o lib",
+      "typecheck": "tsc --noEmit",
-      "test": "jest",
+      "test": "vitest run",
-      "test-coverage": "jest --coverage",
+      "test-coverage": "vitest run --coverage",
       "format": "prettier --write .",
       "format-check": "prettier --check .",
       "prepare": "husky"
@@ -21,24 +21,19 @@
    "author": "GitHub",
    "license": "MIT",
    "dependencies": {
-      "@actions/core": "^2.0.2",
+      "@actions/core": "^3.0.0",
-      "@actions/exec": "^2.0.0",
+      "@actions/exec": "^3.0.0",
-      "@actions/io": "^2.0.0",
+      "@actions/io": "^3.0.2",
       "@kubernetes/client-node": "^1.4.0",
       "husky": "^9.1.7",
       "js-yaml": "^4.1.1"
    },
    "devDependencies": {
-      "@babel/preset-env": "^7.28.6",
-      "@babel/preset-typescript": "^7.28.5",
-      "@types/jest": "^30.0.0",
       "@types/js-yaml": "^4.0.9",
       "@types/node": "^25.0.9",
-      "@vercel/ncc": "^0.38.4",
+      "esbuild": "^0.27.4",
-      "babel-jest": "^30.2.0",
-      "jest": "^30.2.0",
       "prettier": "^3.8.0",
-      "ts-jest": "^29.4.6",
+      "typescript": "^5.9.3",
-      "typescript": "^5.9.3"
+      "vitest": "^4.1.1"
    }
 }

src/action.test.ts

@@ -1,7 +1,9 @@
-import {getRequiredInputError} from '../tests/util'
+import {vi, describe, it, expect} from 'vitest'
-import {run} from './action'
+import {getRequiredInputError} from '../tests/util.js'
-import fs from 'fs'
+import {run} from './action.js'
-import * as utils from './utils'
+
+vi.mock('fs')
+vi.mock('./utils.js')
 
 describe('Run', () => {
    it('throws error without cluster type', async () => {
@@ -9,22 +11,23 @@ describe('Run', () => {
    })
 
    it('writes kubeconfig and sets context', async () => {
+      const {getKubeconfig, setContext} = await import('./utils.js')
+      const fs = await import('fs')
       const kubeconfig = 'kubeconfig'
 
       process.env['INPUT_CLUSTER-TYPE'] = 'default'
       process.env['RUNNER_TEMP'] = '/sample/path'
 
-      jest
+      vi.mocked(getKubeconfig).mockResolvedValue(kubeconfig)
-         .spyOn(utils, 'getKubeconfig')
+      vi.mocked(setContext).mockReturnValue(kubeconfig)
-         .mockImplementation(async () => kubeconfig)
+      vi.mocked(fs.writeFileSync).mockImplementation(() => {})
-      jest.spyOn(fs, 'writeFileSync').mockImplementation(() => {})
+      vi.mocked(fs.chmodSync).mockImplementation(() => {})
-      jest.spyOn(fs, 'chmodSync').mockImplementation(() => {})
-      jest.spyOn(utils, 'setContext').mockImplementation(() => kubeconfig)
 
-      expect(await run())
+      await run()
-      expect(utils.getKubeconfig).toHaveBeenCalled()
+
+      expect(getKubeconfig).toHaveBeenCalled()
       expect(fs.writeFileSync).toHaveBeenCalled()
       expect(fs.chmodSync).toHaveBeenCalled()
-      expect(utils.setContext).toHaveBeenCalled()
+      expect(setContext).toHaveBeenCalled()
    })
 })

src/action.ts

@@ -1,8 +1,8 @@
 import * as core from '@actions/core'
 import * as path from 'path'
 import * as fs from 'fs'
-import {Cluster, parseCluster} from './types/cluster'
+import {Cluster, parseCluster} from './types/cluster.js'
-import {setContext, getKubeconfig} from './utils'
+import {setContext, getKubeconfig} from './utils.js'
 
 /**
  * Sets the Kubernetes context based on supplied action inputs
@@ -14,7 +14,7 @@ export async function run() {
          required: true
       })
    )
-   const runnerTempDirectory: string = process.env['RUNNER_TEMP']
+   const runnerTempDirectory: string = process.env['RUNNER_TEMP'] ?? ''
    const kubeconfigPath: string = path.join(
       runnerTempDirectory,
       `kubeconfig_${Date.now()}`

src/kubeconfigs/arc.test.ts

@@ -1,8 +1,11 @@
-import * as actions from '@actions/exec'
+import {vi, describe, test, it, expect, beforeEach} from 'vitest'
 import * as io from '@actions/io'
-import {getRequiredInputError} from '../../tests/util'
+import {getRequiredInputError} from '../../tests/util.js'
-import {getArcKubeconfig, KUBECONFIG_LOCATION} from './arc'
+import {getArcKubeconfig, KUBECONFIG_LOCATION} from './arc.js'
-import * as az from './azCommands'
+import * as az from './azCommands.js'
+
+vi.mock('@actions/io')
+vi.mock('./azCommands.js')
 
 describe('Arc kubeconfig', () => {
    test('it throws error without resource group', async () => {
@@ -28,11 +31,11 @@ describe('Arc kubeconfig', () => {
          process.env['INPUT_RESOURCE-GROUP'] = group
          process.env['INPUT_CLUSTER-NAME'] = name
 
-         jest.spyOn(io, 'which').mockImplementation(async () => path)
+         vi.mocked(io.which).mockResolvedValue(path)
-         jest.spyOn(az, 'runAzCliCommand').mockImplementation(async () => {})
+         vi.mocked(az.runAzCliCommand).mockResolvedValue(undefined)
-         jest
+         vi.mocked(az.runAzKubeconfigCommandBlocking).mockResolvedValue(
-            .spyOn(az, 'runAzKubeconfigCommandBlocking')
+            kubeconfig
-            .mockImplementation(async () => kubeconfig)
+         )
       })
 
       it('throws an error without method', async () => {

src/kubeconfigs/arc.ts

@@ -1,8 +1,8 @@
 import * as core from '@actions/core'
 import * as io from '@actions/io'
-import {Method, parseMethod} from '../types/method'
+import {Method, parseMethod} from '../types/method.js'
 import * as path from 'path'
-import {runAzCliCommand, runAzKubeconfigCommandBlocking} from './azCommands'
+import {runAzCliCommand, runAzKubeconfigCommandBlocking} from './azCommands.js'
 
 const RUNNER_TEMP: string = process.env['RUNNER_TEMP'] || ''
 export const KUBECONFIG_LOCATION: string = path.join(

src/kubeconfigs/azCommands.test.ts

@@ -1,14 +1,17 @@
+import {vi, describe, test, expect, beforeEach} from 'vitest'
 import * as actions from '@actions/exec'
-import {runAzCliCommand} from './azCommands'
+import {runAzCliCommand} from './azCommands.js'
+
+vi.mock('@actions/exec')
 
 describe('Az commands', () => {
    test('it runs an az cli command', async () => {
       const path = 'path'
       const args = ['args']
 
-      jest.spyOn(actions, 'exec').mockImplementation(async () => 0)
+      vi.mocked(actions.exec).mockResolvedValue(0)
 
-      expect(await runAzCliCommand(path, args))
+      await runAzCliCommand(path, args)
       expect(actions.exec).toHaveBeenCalledWith(path, args, {})
    })
 })

src/kubeconfigs/azCommands.ts

@@ -1,6 +1,5 @@
 import * as fs from 'fs'
-import {ExecOptions} from '@actions/exec/lib/interfaces'
+import {ExecOptions, exec} from '@actions/exec'
-import {exec} from '@actions/exec'
 import {spawn} from 'child_process'
 
 const AZ_TIMEOUT_SECONDS: number = 120

src/kubeconfigs/default.test.ts

@@ -1,7 +1,7 @@
+import {vi, describe, test, expect, beforeEach, afterEach} from 'vitest'
 import * as fs from 'fs'
-import * as core from '@actions/core'
+import {getRequiredInputError} from '../../tests/util.js'
-import {getRequiredInputError} from '../../tests/util'
+import {createKubeconfig, getDefaultKubeconfig} from './default.js'
-import {createKubeconfig, getDefaultKubeconfig} from './default'
 
 describe('Default kubeconfig', () => {
    test('it creates a kubeconfig with proper format', () => {
@@ -51,6 +51,11 @@ describe('Default kubeconfig', () => {
          process.env['INPUT_METHOD'] = 'default'
       })
 
+      afterEach(() => {
+         delete process.env['INPUT_KUBECONFIG']
+         delete process.env['INPUT_KUBECONFIG-ENCODING']
+      })
+
       test('it throws error without kubeconfig', () => {
          expect(() => getDefaultKubeconfig()).toThrow(
             getRequiredInputError('kubeconfig')
@@ -66,39 +71,25 @@ describe('Default kubeconfig', () => {
 
       test('returns kubeconfig as plaintext when encoding is plaintext', () => {
          const kc = 'example kc'
-         jest.spyOn(core, 'getInput').mockImplementation((name: string) => {
+         process.env['INPUT_KUBECONFIG'] = kc
-            if (name === 'method') return 'default'
+         process.env['INPUT_KUBECONFIG-ENCODING'] = 'plaintext'
-            if (name === 'kubeconfig-encoding') return 'plaintext'
+
-            if (name === 'kubeconfig') return kc
-            return ''
-         })
          expect(getDefaultKubeconfig()).toBe(kc)
       })
 
       test('it gets default config through base64 kubeconfig input', () => {
          const kc = 'example kc'
          const base64Kc = Buffer.from(kc, 'utf-8').toString('base64')
-
+         process.env['INPUT_KUBECONFIG'] = base64Kc
-         jest.spyOn(core, 'getInput').mockImplementation((name: string) => {
+         process.env['INPUT_KUBECONFIG-ENCODING'] = 'base64'
-            if (name === 'method') return 'default'
-            if (name === 'kubeconfig-encoding') return 'base64'
-            if (name === 'kubeconfig') return base64Kc
-            return ''
-         })
 
          expect(getDefaultKubeconfig()).toBe(kc)
       })
 
       test('it throws error for unknown kubeconfig-encoding', () => {
          const kc = 'example kc'
-         const unknownEncoding = 'foobar'
+         process.env['INPUT_KUBECONFIG'] = kc
-
+         process.env['INPUT_KUBECONFIG-ENCODING'] = 'foobar'
-         jest.spyOn(core, 'getInput').mockImplementation((name: string) => {
-            if (name === 'method') return 'default'
-            if (name === 'kubeconfig-encoding') return unknownEncoding
-            if (name === 'kubeconfig') return kc
-            return ''
-         })
 
          expect(() => getDefaultKubeconfig()).toThrow(
             "Invalid kubeconfig-encoding: 'foobar'. Must be 'plaintext' or 'base64'."

src/kubeconfigs/default.ts

@@ -1,8 +1,8 @@
 import * as core from '@actions/core'
 import * as jsyaml from 'js-yaml'
 import {KubeConfig} from '@kubernetes/client-node'
-import {K8sSecret, parseK8sSecret} from '../types/k8sSecret'
+import {K8sSecret, parseK8sSecret} from '../types/k8sSecret.js'
-import {Method, parseMethod} from '../types/method'
+import {Method, parseMethod} from '../types/method.js'
 
 /**
  * Gets the kubeconfig based on provided method for a default Kubernetes cluster

src/run.ts

@@ -1,4 +1,4 @@
-import {run} from './action'
+import {run} from './action.js'
 import * as core from '@actions/core'
 
 // Run the application

src/types/cluster.test.ts

@@ -1,8 +1,9 @@
-import {Cluster, parseCluster} from './cluster'
+import {describe, test, expect} from 'vitest'
+import {Cluster, parseCluster} from './cluster.js'
 
 describe('Cluster type', () => {
    test('it has required values', () => {
-      const vals = <any>Object.values(Cluster)
+      const vals = Object.values(Cluster) as string[]
       expect(vals.includes('arc')).toBe(true)
       expect(vals.includes('generic')).toBe(true)
    })

src/types/cluster.ts

@@ -8,9 +8,10 @@ export enum Cluster {
  * @param str The cluster type (case insensitive)
  * @returns The Cluster enum or undefined if it can't be parsed
  */
-export const parseCluster = (str: string): Cluster | undefined =>
+export const parseCluster = (str: string): Cluster | undefined => {
-   Cluster[
+   const key = Object.keys(Cluster).find(
-      Object.keys(Cluster).filter(
+      (k) =>
-         (k) => Cluster[k].toString().toLowerCase() === str.toLowerCase()
+         Cluster[k as keyof typeof Cluster].toLowerCase() === str.toLowerCase()
-      )[0] as keyof typeof Cluster
+   ) as keyof typeof Cluster | undefined
-   ]
+   return key !== undefined ? Cluster[key] : undefined
+}

src/types/k8sSecret.test.ts

@@ -1,4 +1,5 @@
-import {parseK8sSecret, K8sSecret} from './k8sSecret'
+import {describe, test, expect} from 'vitest'
+import {parseK8sSecret} from './k8sSecret.js'
 
 describe('K8sSecret type', () => {
    describe('Parsing from any', () => {

src/types/method.test.ts

@@ -1,8 +1,9 @@
-import {Method, parseMethod} from './method'
+import {describe, test, expect} from 'vitest'
+import {Method, parseMethod} from './method.js'
 
 describe('Method type', () => {
    test('it has required values', () => {
-      const vals = <any>Object.values(Method)
+      const vals = Object.values(Method) as string[]
       expect(vals.includes('kubeconfig')).toBe(true)
       expect(vals.includes('service-account')).toBe(true)
       expect(vals.includes('service-principal')).toBe(true)

src/types/method.ts

@@ -9,9 +9,10 @@ export enum Method {
  * @param str The method (case insensitive)
  * @returns The Method enum or undefined if it can't be parsed
  */
-export const parseMethod = (str: string): Method | undefined =>
+export const parseMethod = (str: string): Method | undefined => {
-   Method[
+   const key = Object.keys(Method).find(
-      Object.keys(Method).filter(
+      (k) =>
-         (k) => Method[k].toString().toLowerCase() === str.toLowerCase()
+         Method[k as keyof typeof Method].toLowerCase() === str.toLowerCase()
-      )[0] as keyof typeof Method
+   ) as keyof typeof Method | undefined
-   ]
+   return key !== undefined ? Method[key] : undefined
+}

src/utils.test.ts

@@ -1,25 +1,26 @@
+import {vi, describe, test, expect} from 'vitest'
 import fs from 'fs'
-import * as arc from './kubeconfigs/arc'
+import * as arc from './kubeconfigs/arc.js'
-import * as def from './kubeconfigs/default'
+import * as def from './kubeconfigs/default.js'
-import {Cluster} from './types/cluster'
+import {Cluster} from './types/cluster.js'
-import {getKubeconfig, setContext} from './utils'
+import {getKubeconfig, setContext} from './utils.js'
 
 describe('Utils', () => {
    describe('get kubeconfig', () => {
       test('it gets arc kubeconfig when type is arc', async () => {
          const arcKubeconfig = 'arckubeconfig'
-         jest
+         vi.spyOn(arc, 'getArcKubeconfig').mockImplementation(
-            .spyOn(arc, 'getArcKubeconfig')
+            async () => arcKubeconfig
-            .mockImplementation(async () => arcKubeconfig)
+         )
 
          expect(await getKubeconfig(Cluster.ARC)).toBe(arcKubeconfig)
       })
 
       test('it defaults to default kubeconfig', async () => {
          const defaultKubeconfig = 'arckubeconfig'
-         jest
+         vi.spyOn(def, 'getDefaultKubeconfig').mockImplementation(
-            .spyOn(def, 'getDefaultKubeconfig')
+            () => defaultKubeconfig
-            .mockImplementation(() => defaultKubeconfig)
+         )
 
          expect(await getKubeconfig(undefined)).toBe(defaultKubeconfig)
          expect(await getKubeconfig(Cluster.GENERIC)).toBe(defaultKubeconfig)

src/utils.ts

@@ -1,9 +1,9 @@
 import * as core from '@actions/core'
 import * as fs from 'fs'
 import {KubeConfig} from '@kubernetes/client-node'
-import {getDefaultKubeconfig} from './kubeconfigs/default'
+import {getDefaultKubeconfig} from './kubeconfigs/default.js'
-import {getArcKubeconfig} from './kubeconfigs/arc'
+import {getArcKubeconfig} from './kubeconfigs/arc.js'
-import {Cluster} from './types/cluster'
+import {Cluster} from './types/cluster.js'
 
 /**
  * Gets the kubeconfig based on Kubernetes cluster type

tsconfig.json

@@ -1,15 +1,14 @@
 {
    "compilerOptions": {
-      "baseUrl": ".",
+      "target": "ES2020",
-      "module": "ESNext", // or "NodeNext" depending on your setup
+      "module": "NodeNext",
-      "moduleResolution": "node",
+      "moduleResolution": "NodeNext",
-      "esModuleInterop": true,
+      "rootDir": "./src",
-      "allowSyntheticDefaultImports": true,
+      "outDir": "./lib",
+      "noImplicitAny": false,
       "skipLibCheck": true,
-      "paths": {
+      "noEmit": true,
-         "@actions/core": ["node_modules/@actions/core"],
+      "types": ["node", "vitest/globals"]
-         "@kubernetes/client-node": ["node_modules/@kubernetes/client-node"]
-      }
    },
-   "exclude": ["node_modules", "tests", "src/**/*.test.ts"]
+   "exclude": ["node_modules", "**/*.test.ts", "vitest.config.ts", "tests/"]
 }

vitest.config.ts

@@ -0,0 +1,10 @@
+import {defineConfig} from 'vitest/config'
+
+export default defineConfig({
+   test: {
+      globals: true,
+      environment: 'node',
+      include: ['**/*.test.ts'],
+      clearMocks: true
+   }
+})