Add webpack option (#375)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

Author: dflupu

Diff for: lib/options-manager.js

@@ -8,6 +8,7 @@ const mergeWith = require('lodash/mergeWith');
 const groupBy = require('lodash/groupBy');
 const flow = require('lodash/flow');
 const pathExists = require('path-exists');
+const findUp = require('find-up');
 const findCacheDir = require('find-cache-dir');
 const resolveFrom = require('resolve-from');
 const prettier = require('prettier');
@@ -313,14 +314,13 @@ const buildXOConfig = options => config => {
 		Object.assign(config.rules, options.rules);
 	}
 
-	if (options.settings) {
-		config.baseConfig.settings = options.settings;
-	}
-
 	if (options.parser) {
 		config.baseConfig.parser = options.parser;
 	}
 
+	config.baseConfig.settings = options.settings || {};
+	config.baseConfig.settings['import/resolver'] = gatherImportResolvers(options);
+
 	return config;
 };
 
@@ -476,6 +476,43 @@ const findApplicableOverrides = (path, overrides) => {
 
 const getIgnores = ({ignores}) => DEFAULT_IGNORES.concat(ignores || []);
 
+const gatherImportResolvers = options => {
+	let resolvers = {};
+
+	const resolverSettings = options.settings && options.settings['import/resolver'];
+	if (resolverSettings) {
+		if (typeof resolverSettings === 'string') {
+			resolvers[resolverSettings] = {};
+		} else {
+			resolvers = {...resolverSettings};
+		}
+	}
+
+	let webpackResolverSettings;
+
+	if (options.webpack) {
+		webpackResolverSettings = options.webpack === true ? {} : options.webpack;
+	} else if (!(options.webpack === false || resolvers.webpack)) {
+		// If a webpack config file exists, add the import resolver automatically
+		const webpackConfigPath = findUp.sync('webpack.config.js', {cwd: options.cwd});
+		if (webpackConfigPath) {
+			webpackResolverSettings = {config: webpackConfigPath};
+		}
+	}
+
+	if (webpackResolverSettings) {
+		resolvers = {
+			...resolvers,
+			webpack: {
+				...resolvers.webpack,
+				...webpackResolverSettings
+			}
+		};
+	}
+
+	return resolvers;
+};
+
 module.exports = {
 	findApplicableOverrides,
 	mergeWithPrettierConfig,

Diff for: package.json

@@ -61,6 +61,7 @@
 		"eslint-config-xo": "^0.29.0",
 		"eslint-config-xo-typescript": "^0.26.0",
 		"eslint-formatter-pretty": "^3.0.1",
+		"eslint-import-resolver-webpack": "^0.12.1",
 		"eslint-plugin-ava": "^10.0.1",
 		"eslint-plugin-eslint-comments": "^3.1.2",
 		"eslint-plugin-import": "^2.20.1",
@@ -70,6 +71,7 @@
 		"eslint-plugin-promise": "^4.2.1",
 		"eslint-plugin-unicorn": "^17.2.0",
 		"find-cache-dir": "^3.0.0",
+		"find-up": "^4.1.0",
 		"fs-extra": "^8.1.0",
 		"get-stdin": "^7.0.0",
 		"globby": "^9.0.0",
@@ -103,7 +105,8 @@
 		"nyc": "^15.0.0",
 		"pify": "^4.0.0",
 		"proxyquire": "^2.1.3",
-		"temp-write": "^4.0.0"
+		"temp-write": "^4.0.0",
+		"webpack": "^4.42.0"
 	},
 	"eslintConfig": {
 		"extends": "eslint-config-xo"

Diff for: readme.md

@@ -252,7 +252,7 @@ Allow more extensions to be linted besides `.js` and `.jsx`. Make sure they're s
 
 Type: `object`
 
-[Shared ESLint settings](https://eslint.org/docs/user-guide/configuring#adding-shared-settings) exposed to rules. For example, to configure the [`import`](https://github.com/benmosher/eslint-plugin-import#settings) plugin to use your webpack configuration for determining search paths, you can put `{"import/resolver": "webpack"}` here.
+[Shared ESLint settings](https://eslint.org/docs/user-guide/configuring#adding-shared-settings) exposed to rules.
 
 ### parser
 
@@ -269,6 +269,17 @@ Enforce ES2015+ rules. Disabling this will make it not *enforce* ES2015+ syntax
 
 *ES2015+ is parsed even without this option. You can already use ES2017 features like [`async`/`await`](https://github.com/lukehoban/ecmascript-asyncawait).
 
+### webpack
+
+Type: `boolean | object`
+Default: `false`
+
+Use [eslint-import-resolver-webpack](https://github.com/benmosher/eslint-plugin-import/tree/master/resolvers/webpack) to resolve import search paths. This is enabled automatically if a `webpack.config.js` file is found.
+
+Set this to a boolean to explicitly enable or disable the resolver.
+
+Setting this to an object enables the resolver and passes the object as configuration. See the [resolver readme](https://github.com/benmosher/eslint-plugin-import/blob/master/resolvers/webpack/README.md) along with the [webpack documentation](https://webpack.js.org/configuration/resolve/) for more information.
+
 ## TypeScript and Flow
 
 ### TypeScript
@@ -368,7 +379,7 @@ For example, if your project targets Node.js 8 but you want to use the latest Ja
 }
 ```
 
-This way your `package.json` will contain the actual minimum Node.js version supported by your published code, but XO will lint your source code as if it targets Node.js 12. 
+This way your `package.json` will contain the actual minimum Node.js version supported by your published code, but XO will lint your source code as if it targets Node.js 12.
 
 ### Including files ignored by default
 

Diff for: test/fixtures/webpack/no-config/file1.js

@@ -0,0 +1,2 @@
+import _ from 'file2alias'; // eslint-disable-line no-unused-vars
+import __ from 'inexistent'; // eslint-disable-line no-unused-vars

Diff for: test/fixtures/webpack/no-config/file2.js

@@ -0,0 +1,2 @@
+const foo = 1;
+export default foo;

Diff for: test/fixtures/webpack/no-config/file3.js

@@ -0,0 +1 @@
+import _ from '!./file2'; // eslint-disable-line no-unused-vars

Diff for: test/fixtures/webpack/with-config/file1.js

@@ -0,0 +1,2 @@
+import _ from 'file2alias'; // eslint-disable-line no-unused-vars
+import __ from 'inexistent'; // eslint-disable-line no-unused-vars

Diff for: test/fixtures/webpack/with-config/file2.js

@@ -0,0 +1,2 @@
+const foo = 1;
+export default foo;

Diff for: test/fixtures/webpack/with-config/webpack.config.js

@@ -0,0 +1,9 @@
+const path = require('path');
+
+module.exports = {
+	resolve: {
+		alias: {
+			file2alias: path.resolve(__dirname, 'file2.js')
+		}
+	}
+};

Diff for: test/lint-files.js

@@ -196,6 +196,58 @@ test('typescript files', async t => {
 	);
 });
 
+test('webpack import resolver is used if webpack.config.js is found', async t => {
+	const cwd = 'fixtures/webpack/with-config/';
+	const {results} = await fn.lintFiles(path.resolve(cwd, 'file1.js'), {
+		cwd,
+		rules: {
+			'import/no-unresolved': 2
+		}
+	});
+
+	t.is(results[0].errorCount, 1);
+
+	const errorMessage = results[0].messages[0].message;
+	t.truthy(/Unable to resolve path to module 'inexistent'/.exec(errorMessage));
+});
+
+test('webpack import resolver config can be passed through webpack option', async t => {
+	const cwd = 'fixtures/webpack/no-config/';
+
+	const {results} = await fn.lintFiles(path.resolve(cwd, 'file1.js'), {
+		cwd,
+		webpack: {
+			config: {
+				resolve: {
+					alias: {
+						file2alias: path.resolve(__dirname, cwd, './file2.js')
+					}
+				}
+			}
+		},
+		rules: {
+			'import/no-unresolved': 2
+		}
+	});
+
+	t.is(results[0].errorCount, 1);
+});
+
+test('webpack import resolver is used if {webpack: true}', async t => {
+	const cwd = 'fixtures/webpack/no-config/';
+
+	const {results} = await fn.lintFiles(path.resolve(cwd, 'file3.js'), {
+		cwd,
+		webpack: true,
+		rules: {
+			'import/no-unresolved': 2,
+			'import/no-webpack-loader-syntax': 0
+		}
+	});
+
+	t.is(results[0].errorCount, 0);
+});
+
 async function configType(t, {dir}) {
 	const {results} = await fn.lintFiles('**/*', {cwd: path.resolve('fixtures', 'config-files', dir)});
 

Diff for: test/options-manager.js

@@ -384,11 +384,40 @@ test('buildConfig: parser', t => {
 });
 
 test('buildConfig: settings', t => {
-	const settings = {'import/resolver': 'webpack'};
+	const settings = {'import/resolver': {webpack: {}}};
 	const config = manager.buildConfig({settings});
 	t.deepEqual(config.baseConfig.settings, settings);
 });
 
+test('buildConfig: finds webpack config file', t => {
+	const cwd = path.resolve('fixtures', 'webpack', 'with-config');
+	const config = manager.buildConfig({cwd});
+	const expected = {webpack: {config: path.resolve(cwd, 'webpack.config.js')}};
+	t.deepEqual(config.baseConfig.settings['import/resolver'], expected);
+});
+
+test('buildConfig: webpack option sets resolver', t => {
+	const config = manager.buildConfig({webpack: true, settings: {'import/resolver': 'node'}});
+	t.deepEqual(config.baseConfig.settings['import/resolver'], {webpack: {}, node: {}});
+});
+
+test('buildConfig: webpack option handles object values', t => {
+	const config = manager.buildConfig({webpack: {foo: 1}, settings: {'import/resolver': 'node'}});
+	t.deepEqual(config.baseConfig.settings['import/resolver'], {webpack: {foo: 1}, node: {}});
+});
+
+test('buildConfig: webpack resolver is not added automatically if webpack option is set to false', t => {
+	const cwd = path.resolve('fixtures', 'webpack', 'with-config');
+	const config = manager.buildConfig({cwd, webpack: false, settings: {}});
+	t.deepEqual(config.baseConfig.settings['import/resolver'], {});
+});
+
+test('buildConfig: webpack option is merged with import/resolver', t => {
+	const settings = {'import/resolver': {webpack: {bar: 1}}};
+	const config = manager.buildConfig({settings, webpack: {foo: 1}});
+	t.deepEqual(config.baseConfig.settings['import/resolver'], {webpack: {foo: 1, bar: 1}});
+});
+
 test('buildConfig: extends', t => {
 	const config = manager.buildConfig({extends: [
 		'plugin:foo/bar',