import { RuleTester as ESLintTesterV8 } from 'eslint-v8' import { RuleTester as ESLintTesterV9 } from 'eslint' import { rules } from '@next/eslint-plugin-next' const NextESLintRule = rules['no-async-client-component'] const message = 'Prevent Client Components from being async functions. See: https://nextjs.org/docs/messages/no-async-client-component' const tests = { valid: [ ` // single line export default async function MyComponent() { return <> } `, ` // single line capitalization "use client" export default async function myFunction() { return '' } `, ` // multiple line async function MyComponent() { return <> } export default MyComponent `, ` // multiple line capitalization "use client" async function myFunction() { return '' } export default myFunction `, ` // arrow function "use client" const myFunction = () => { return '' } export default myFunction `, ], invalid: [ { code: ` // single line "use client" export default async function MyComponent() { return <> } `, errors: [{ message }], }, { code: ` // single line capitalization "use client" export default async function MyFunction() { return '' } `, errors: [{ message }], }, { code: ` // multiple line "use client" async function MyComponent() { return <> } export default MyComponent `, errors: [{ message }], }, { code: ` // multiple line capitalization "use client" async function MyFunction() { return '' } export default MyFunction `, errors: [{ message }], }, { code: ` // arrow function "use client" const MyFunction = async () => { return '123' } export default MyFunction `, errors: [{ message }], }, ], } describe('no-async-client-component', () => { new ESLintTesterV8({ parserOptions: { ecmaVersion: 2018, sourceType: 'module', ecmaFeatures: { modules: true, jsx: true, }, }, }).run('eslint-v8', NextESLintRule, tests) new ESLintTesterV9({ languageOptions: { ecmaVersion: 2018, sourceType: 'module', parserOptions: { ecmaFeatures: { modules: true, jsx: true, }, }, }, }).run('eslint-v9', NextESLintRule, tests) })