index.js

@@ -147,6 +147,17 @@ const meow = (helpText, options = {}) => {
 		delete parserOptions.arguments;
 	}
 
+	// Add --help and --version to known flags if autoHelp or autoVersion are set
+	if (!options.allowUnknownFlags) {
+		if (options.autoHelp) {
+			parserOptions.help = {type: 'boolean'};
+		}
+
+		if (options.autoVersion) {
+			parserOptions.version = {type: 'boolean'};
+		}
+	}
+
 	parserOptions = buildParserOptions(parserOptions);
 
 	parserOptions.configuration = {

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "meow",
-	"version": "10.1.3",
+	"version": "10.1.4",
 	"description": "CLI app helper",
 	"license": "MIT",
 	"repository": "sindresorhus/meow",

test/allow-unknown-flags.js

@@ -0,0 +1,63 @@
+import path from 'node:path';
+import {fileURLToPath} from 'node:url';
+import test from 'ava';
+import indentString from 'indent-string';
+import {execa} from 'execa';
+import {readPackage} from 'read-pkg';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const fixtureAllowUnknownFlags = path.join(__dirname, 'fixtures', 'fixture-allow-unknown-flags.js');
+
+test('spawn CLI and test specifying unknown flags', async t => {
+	const error = await t.throwsAsync(
+		execa(fixtureAllowUnknownFlags, ['--foo', 'bar', '--unspecified-a', '--unspecified-b', 'input-is-allowed']),
+		{
+			message: /^Command failed with exit code 2/,
+		},
+	);
+	const {stderr} = error;
+	t.regex(stderr, /Unknown flags/);
+	t.regex(stderr, /--unspecified-a/);
+	t.regex(stderr, /--unspecified-b/);
+	t.notRegex(stderr, /input-is-allowed/);
+});
+
+test('spawn CLI and test specifying known flags', async t => {
+	const {stdout} = await execa(fixtureAllowUnknownFlags, ['--foo', 'bar']);
+	t.is(stdout, 'bar');
+});
+
+test('spawn CLI and test help as a known flag', async t => {
+	const {stdout} = await execa(fixtureAllowUnknownFlags, ['--help']);
+	t.is(stdout, indentString('\nCustom description\n\nUsage\n  foo <input>\n\n', 2));
+});
+
+test('spawn CLI and test version as a known flag', async t => {
+	const pkg = await readPackage();
+	const {stdout} = await execa(fixtureAllowUnknownFlags, ['--version']);
+	t.is(stdout, pkg.version);
+});
+
+test('spawn CLI and test help as an unknown flag', async t => {
+	const error = await t.throwsAsync(
+		execa(fixtureAllowUnknownFlags, ['--help', '--no-auto-help']),
+		{
+			message: /^Command failed with exit code 2/,
+		},
+	);
+	const {stderr} = error;
+	t.regex(stderr, /Unknown flag/);
+	t.regex(stderr, /--help/);
+});
+
+test('spawn CLI and test version as an unknown flag', async t => {
+	const error = await t.throwsAsync(
+		execa(fixtureAllowUnknownFlags, ['--version', '--no-auto-version']),
+		{
+			message: /^Command failed with exit code 2/,
+		},
+	);
+	const {stderr} = error;
+	t.regex(stderr, /Unknown flag/);
+	t.regex(stderr, /--version/);
+});

test/fixtures/fixture-allow-unknown-flags.js

@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+import process from 'node:process';
 import meow from '../../index.js';
 
 const cli = meow({
@@ -8,11 +9,20 @@ const cli = meow({
 		Usage
 		  foo <input>
   `,
+	autoVersion: !process.argv.includes('--no-auto-version'),
+	autoHelp: !process.argv.includes('--no-auto-help'),
 	allowUnknownFlags: false,
 	flags: {
 		foo: {
 			type: 'string',
 		},
+		// For testing we need those as known flags
+		noAutoHelp: {
+			type: 'boolean',
+		},
+		noAutoVersion: {
+			type: 'boolean',
+		},
 	},
 });