.editorconfig

@@ -7,9 +7,6 @@ charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
 
-[{package.json,*.yml}]
+[*.yml]
 indent_style = space
 indent_size = 2
-
-[*.md]
-trim_trailing_whitespace = false

.gitattributes

@@ -1,2 +1,2 @@
-* text=auto
+* text=auto eol=lf
 *.ai binary

.github/workflows/main.yml

@@ -0,0 +1,26 @@
+name: CI
+on:
+  - push
+  - pull_request
+jobs:
+  test:
+    name: Node.js ${{ matrix.node-version }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version:
+          - 16
+          - 14
+          - 12
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node-version }}
+      - run: npm install
+      - run: npm test
+      - uses: codecov/codecov-action@v1
+        if: matrix.node-version == 14
+        with:
+          fail_ci_if_error: true

.gitignore

@@ -1 +1,6 @@
 node_modules
+yarn.lock
+!test/fixtures/project/node_modules
+test/fixtures/project/node_modules/.cache
+.nyc_output
+coverage

.npmrc

@@ -0,0 +1 @@
+package-lock=false

cli.js

@@ -1,80 +1,222 @@
 #!/usr/bin/env node
-'use strict';
-var updateNotifier = require('update-notifier');
-var getStdin = require('get-stdin');
-var meow = require('meow');
-var xo = require('./');
-
-var cli = meow({
-	help: [
-		'Usage',
-		'  $ xo [<file|glob> ...]',
-		'',
-		'Options',
-		'  --init          Add XO to your project',
-		'  --compact       Compact output',
-		'  --stdin         Validate code from stdin',
-		'  --esnext        Enable ES2015 support and rules',
-		'  --env           Environment preset  [Can be set multiple times]',
-		'  --global        Global variable  [Can be set multiple times]',
-		'  --ignore        Additional paths to ignore  [Can be set multiple times]',
-		'  --space         Use space indent instead of tabs  [Default: 2]',
-		'  --no-semicolon  Prevent use of semicolons',
-		'',
-		'Examples',
-		'  $ xo',
-		'  $ xo index.js',
-		'  $ xo *.js !foo.js',
-		'  $ xo --esnext --space',
-		'  $ xo --esnext --env=node --env=mocha',
-		'',
-		'Tips',
-		'  Put options in package.json instead of using flags so other tools can read it.'
-	]
-}, {
-	string: [
-		'_'
-	],
-	boolean: [
-		'init',
-		'compact',
-		'stdin'
-	]
+import getStdin from 'get-stdin';
+import meow from 'meow';
+import formatterPretty from 'eslint-formatter-pretty';
+import semver from 'semver';
+import openReport from './lib/open-report.js';
+import xo from './index.js';
+
+const cli = meow(`
+	Usage
+	  $ xo [<file|glob> ...]
+
+	Options
+	  --fix             Automagically fix issues
+	  --reporter        Reporter to use
+	  --env             Environment preset  [Can be set multiple times]
+	  --global          Global variable  [Can be set multiple times]
+	  --ignore          Additional paths to ignore  [Can be set multiple times]
+	  --space           Use space indent instead of tabs  [Default: 2]
+	  --no-semicolon    Prevent use of semicolons
+	  --prettier        Conform to Prettier code style
+	  --node-version    Range of Node.js version to support
+	  --plugin          Include third-party plugins  [Can be set multiple times]
+	  --extend          Extend defaults with a custom config  [Can be set multiple times]
+	  --open            Open files with issues in your editor
+	  --quiet           Show only errors and no warnings
+	  --extension       Additional extension to lint [Can be set multiple times]
+	  --cwd=<dir>       Working directory for files
+	  --stdin           Validate/fix code from stdin
+	  --stdin-filename  Specify a filename for the --stdin option
+	  --print-config    Print the effective ESLint config for the given file
+
+	Examples
+	  $ xo
+	  $ xo index.js
+	  $ xo *.js !foo.js
+	  $ xo --space
+	  $ xo --env=node --env=mocha
+	  $ xo --plugin=react
+	  $ xo --plugin=html --extension=html
+	  $ echo 'const x=true' | xo --stdin --fix
+	  $ xo --print-config=index.js
+
+	Tips
+	  - Add XO to your project with \`npm init xo\`.
+	  - Put options in package.json instead of using flags so other tools can read it.
+`, {
+	importMeta: import.meta,
+	autoVersion: false,
+	booleanDefault: undefined,
+	flags: {
+		fix: {
+			type: 'boolean',
+		},
+		reporter: {
+			type: 'string',
+		},
+		env: {
+			type: 'string',
+			isMultiple: true,
+		},
+		global: {
+			type: 'string',
+			isMultiple: true,
+		},
+		ignore: {
+			type: 'string',
+			isMultiple: true,
+		},
+		space: {
+			type: 'string',
+		},
+		semicolon: {
+			type: 'boolean',
+		},
+		prettier: {
+			type: 'boolean',
+		},
+		nodeVersion: {
+			type: 'string',
+		},
+		plugin: {
+			type: 'string',
+			isMultiple: true,
+		},
+		extend: {
+			type: 'string',
+			isMultiple: true,
+		},
+		open: {
+			type: 'boolean',
+		},
+		quiet: {
+			type: 'boolean',
+		},
+		extension: {
+			type: 'string',
+			isMultiple: true,
+		},
+		cwd: {
+			type: 'string',
+		},
+		printConfig: {
+			type: 'string',
+		},
+		stdin: {
+			type: 'boolean',
+		},
+		stdinFilename: {
+			type: 'string',
+		},
+	},
 });
 
-updateNotifier({pkg: cli.pkg}).notify();
+const {input, flags: options, showVersion} = cli;
 
-var input = cli.input;
-var opts = cli.flags;
+// TODO: Fix this properly instead of the below workaround.
+// Revert behavior of meow >8 to pre-8 (7.1.1) for flags using `isMultiple: true`.
+// Otherwise, options defined in package.json can't be merged by lib/options-manager.js `mergeOptions()`.
+for (const key in options) {
+	if (Array.isArray(options[key]) && options[key].length === 0) {
+		delete options[key];
+	}
+}
 
-function log(report) {
-	process.stdout.write(xo.getFormatter(opts.compact && 'compact')(report.results));
-	process.exit(report.errorCount === 0 ? 0 : 1);
+// Make data types for `options.space` match those of the API
+// Check for string type because `xo --no-space` sets `options.space` to `false`
+if (typeof options.space === 'string') {
+	if (/^\d+$/u.test(options.space)) {
+		options.space = Number.parseInt(options.space, 10);
+	} else if (options.space === 'true') {
+		options.space = true;
+	} else if (options.space === 'false') {
+		options.space = false;
+	} else {
+		if (options.space !== '') {
+			// Assume `options.space` was set to a filename when run as `xo --space file.js`
+			input.push(options.space);
+		}
+
+		options.space = true;
+	}
 }
 
-if (opts.init) {
-	require('xo-init')();
-	return;
+if (process.env.GITHUB_ACTIONS && !options.fix && !options.reporter) {
+	options.quiet = true;
 }
 
+const log = async report => {
+	const reporter = options.reporter || process.env.GITHUB_ACTIONS ? await xo.getFormatter(options.reporter || 'compact') : formatterPretty;
+	process.stdout.write(reporter(report.results));
+	process.exitCode = report.errorCount === 0 ? 0 : 1;
+};
+
 // `xo -` => `xo --stdin`
 if (input[0] === '-') {
-	opts.stdin = true;
+	options.stdin = true;
 	input.shift();
 }
 
-if (opts.stdin) {
-	getStdin(function (str) {
-		log(xo.lintText(str));
-	});
-
-	return;
+if (options.version) {
+	showVersion();
 }
 
-xo.lintFiles(input, opts, function (err, report) {
-	if (err) {
-		throw err;
+if (options.nodeVersion) {
+	if (options.nodeVersion === 'false') {
+		options.nodeVersion = false;
+	} else if (!semver.validRange(options.nodeVersion)) {
+		console.error('The `--node-engine` flag must be a valid semver range (for example `>=6`)');
+		process.exit(1);
 	}
+}
 
-	log(report);
-});
+(async () => {
+	if (options.printConfig) {
+		if (input.length > 0) {
+			console.error('The `--print-config` flag must be used with exactly one filename');
+			process.exit(1);
+		}
+
+		if (options.stdin) {
+			console.error('The `--print-config` flag is not supported on stdin');
+			process.exit(1);
+		}
+
+		options.filePath = options.printConfig;
+		const config = await xo.getConfig(options);
+		console.log(JSON.stringify(config, undefined, '\t'));
+	} else if (options.stdin) {
+		const stdin = await getStdin();
+
+		if (options.stdinFilename) {
+			options.filePath = options.stdinFilename;
+		}
+
+		if (options.fix) {
+			const {results: [result]} = await xo.lintText(stdin, options);
+			// If there is no output, pass the stdin back out
+			process.stdout.write((result && result.output) || stdin);
+			return;
+		}
+
+		if (options.open) {
+			console.error('The `--open` flag is not supported on stdin');
+			process.exit(1);
+		}
+
+		await log(await xo.lintText(stdin, options));
+	} else {
+		const report = await xo.lintFiles(input, options);
+
+		if (options.fix) {
+			await xo.outputFixes(report);
+		}
+
+		if (options.open) {
+			openReport(report);
+		}
+
+		await log(report);
+	}
+})();