Add node/no-unsupported-features rules

Author: pvdlg

config/plugins.js

@@ -185,9 +185,6 @@ module.exports = {
 		// 	}
 		// ],
 
-		// Disabled as the rule doesn't allow to exclude compiled sources
-		// 'node/no-unsupported-features': 'error',
-
 		'node/process-exit-as-throw': 'error',
 
 		// Disabled as the rule doesn't exclude scripts executed with `node` but not referenced in 'bin'. See https://github.com/mysticatea/eslint-plugin-node/issues/96

lib/options-manager.js

@@ -195,6 +195,12 @@ const buildXOConfig = options => config => {
 		}
 	}
 
+	if (options.nodeVersion) {
+		config.rules['node/no-unsupported-features/es-builtins'] = ['error', {version: options.nodeVersion}];
+		config.rules['node/no-unsupported-features/es-syntax'] = ['error', {version: options.nodeVersion, ignores: ['modules']}];
+		config.rules['node/no-unsupported-features/node-builtins'] = ['error', {version: options.nodeVersion}];
+	}
+
 	if (options.space && !options.prettier) {
 		config.rules.indent = ['error', spaces, {SwitchCase: 1}];
 

readme.md

@@ -336,23 +336,37 @@ Put a `package.json` with your config at the root and omit the `xo` property in
 
 ### Transpilation
 
-If some files in your project are transpiled in order to support an older Node.js version, you can use the [config overrides](#config-overrides) option to set a specific [`nodeVersion`](#nodeversion) target for these files.
+If some files in your project are transpiled in order to support an older Node.js version, you can use the [config overrides](#config-overrides) option to set a specific [`nodeVersion`](#nodeversion) to target your sources files.
 
-For example, if your project targets Node.js 4 (your `package.json` is configured with `engines.node` set to `>=4`) and you are using [AVA](https://github.com/avajs/ava), then your test files are automatically transpiled. You can override `nodeVersion` for the tests files:
+For example, if your project targets Node.js 8 but you want to use the latest JavaScript syntax as supported in Node.js 12:
+1. Set the `engines.node` property of your `package.json` to `>=8`
+2. Configure [Babel](https://babeljs.io) to transpile your source files (in `src` directory in this example)
+3. Make sure to include the transpiled files in your published package with the [`files`](https://docs.npmjs.com/files/package.json#files) and [`main`](https://docs.npmjs.com/files/package.json#main) properties of your `package.json`
+4. Configure the XO `overrides` option to set `nodeVersion` to `>=12` for your source files directory
 
 ```json
 {
+	"engines": {
+		"node": ">=8"
+	},
+	"scripts": {
+		"build": "babel src --out-dir dist"
+	},
+	"main": "dist/index.js",
+	"files": ["dist/**/*.js"],
 	"xo": {
 		"overrides": [
 			{
-				"files": "{test,tests,spec,__tests__}/**/*.js",
-				"nodeVersion": ">=9"
+				"files": "{src}/**/*.js",
+				"nodeVersion": ">=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
 
 To include files that XO [ignores by default](https://github.com/xojs/xo/blob/master/lib/constants.js#L1), add them as negative globs in the `ignores` option:
@@ -367,7 +381,6 @@ To include files that XO [ignores by default](https://github.com/xojs/xo/blob/ma
 }
 ```
 
-
 ## FAQ
 
 #### What does XO mean?

test/options-manager.js

@@ -67,13 +67,8 @@ test('buildConfig: space: 4', t => {
 
 test('buildConfig: semicolon', t => {
 	const config = manager.buildConfig({semicolon: false, nodeVersion: '12'});
-	t.deepEqual(config.rules, {
-		semi: ['error', 'never'],
-		'semi-spacing': ['error', {
-			before: false,
-			after: true
-		}]
-	});
+	t.deepEqual(config.rules.semi, ['error', 'never']);
+	t.deepEqual(config.rules['semi-spacing'], ['error', {before: false, after: true}]);
 });
 
 test('buildConfig: prettier: true', t => {
@@ -211,6 +206,9 @@ test('buildConfig: engines: undefined', t => {
 	t.is(config.rules['unicorn/prefer-flat-map'], 'off');
 	t.is(config.rules['node/prefer-promises/dns'], 'off');
 	t.is(config.rules['node/prefer-promises/fs'], 'off');
+	t.is(config.rules['node/no-unsupported-features/es-builtins'], undefined);
+	t.is(config.rules['node/no-unsupported-features/es-syntax'], undefined);
+	t.is(config.rules['node/no-unsupported-features/node-builtins'], undefined);
 });
 
 test('buildConfig: nodeVersion: false', t => {
@@ -226,31 +224,32 @@ test('buildConfig: nodeVersion: false', t => {
 	t.is(config.rules['node/prefer-promises/fs'], 'off');
 });
 
-test('buildConfig: nodeVersion: invalid range', t => {
-	const config = manager.buildConfig({nodeVersion: '4'});
-
-	// Override all the rules specific to Node.js version
-	t.is(config.rules['prefer-object-spread'], 'off');
-	t.is(config.rules['prefer-rest-params'], 'off');
-	t.is(config.rules['prefer-destructuring'], 'off');
-	t.is(config.rules['promise/prefer-await-to-then'], 'off');
-	t.is(config.rules['unicorn/prefer-flat-map'], 'off');
-	t.is(config.rules['node/prefer-promises/dns'], 'off');
-	t.is(config.rules['node/prefer-promises/fs'], 'off');
-});
-
 test('buildConfig: nodeVersion: >=6', t => {
 	const config = manager.buildConfig({nodeVersion: '>=6'});
 
 	// Turn off rule if we support Node.js below 7.6.0
 	t.is(config.rules['promise/prefer-await-to-then'], 'off');
+	// Set node/no-unsupported-features rules with the nodeVersion
+	t.deepEqual(config.rules['node/no-unsupported-features/es-builtins'], ['error', {version: '>=6'}]);
+	t.deepEqual(
+		config.rules['node/no-unsupported-features/es-syntax'],
+		['error', {version: '>=6', ignores: ['modules']}]
+	);
+	t.deepEqual(config.rules['node/no-unsupported-features/node-builtins'], ['error', {version: '>=6'}]);
 });
 
 test('buildConfig: nodeVersion: >=8', t => {
 	const config = manager.buildConfig({nodeVersion: '>=8'});
 
 	// Do not turn off rule if we support only Node.js above 7.6.0
 	t.is(config.rules['promise/prefer-await-to-then'], undefined);
+	// Set node/no-unsupported-features rules with the nodeVersion
+	t.deepEqual(config.rules['node/no-unsupported-features/es-builtins'], ['error', {version: '>=8'}]);
+	t.deepEqual(
+		config.rules['node/no-unsupported-features/es-syntax'],
+		['error', {version: '>=8', ignores: ['modules']}]
+	);
+	t.deepEqual(config.rules['node/no-unsupported-features/node-builtins'], ['error', {version: '>=8'}]);
 });
 
 test('mergeWithPrettierConfig: use `singleQuote`, `trailingComma`, `bracketSpacing` and `jsxBracketSameLine` from `prettier` config if defined', t => {
@@ -344,7 +343,7 @@ test('mergeWithPrettierConfig: throw error is `space`/`tabWidth` conflicts', t =
 test('buildConfig: rules', t => {
 	const rules = {'object-curly-spacing': ['error', 'always']};
 	const config = manager.buildConfig({rules, nodeVersion: '12'});
-	t.deepEqual(config.rules, rules);
+	t.deepEqual(config.rules['object-curly-spacing'], rules['object-curly-spacing']);
 });
 
 test('buildConfig: parser', t => {