[BREAKING] ES2015ify and require Node.js >=4

ESLint now requires Node.js >=4, so no point in us supporting lower. http://eslint.org/blog/2016/07/eslint-v3.0.0-released#requires-nodejs-4-or-higher

Author: sindresorhus

.travis.yml

@@ -1,10 +1,7 @@
 language: node_js
 node_js:
   - '6'
-  - '5'
   - '4'
-  - '0.12'
-  - '0.10'
 before_install:
   - npm i -g npm
 after_success: npm run coveralls

package.json

@@ -22,7 +22,7 @@
     }
   ],
   "engines": {
-    "node": ">=0.10.0"
+    "node": ">=4"
   },
   "scripts": {
     "test": "xo && nyc ava",
@@ -59,5 +59,8 @@
   },
   "peerDependencies": {
     "eslint": ">=2"
+  },
+  "xo": {
+    "esnext": true
   }
 }

rules/catch-error-name.js

@@ -1,14 +1,14 @@
 'use strict';
 
-// Matches someObj.then([FunctionExpression | ArrowFunctionExpression])
+// matches someObj.then([FunctionExpression | ArrowFunctionExpression])
 function isLintablePromiseCatch(node) {
-	var callee = node.callee;
+	const callee = node.callee;
 
 	if (callee.type !== 'MemberExpression') {
 		return false;
 	}
 
-	var property = callee.property;
+	const property = callee.property;
 
 	if (property.type !== 'Identifier' || property.name !== 'catch') {
 		return false;
@@ -18,16 +18,15 @@ function isLintablePromiseCatch(node) {
 		return false;
 	}
 
-	var arg0 = node.arguments[0];
+	const arg0 = node.arguments[0];
 
 	return arg0.type === 'FunctionExpression' || arg0.type === 'ArrowFunctionExpression';
 }
 
 module.exports = function (context) {
-	var opts = context.options[0];
-	var name = (opts && opts.name) || 'err';
-
-	var stack = [];
+	const opts = context.options[0];
+	const name = (opts && opts.name) || 'err';
+	const stack = [];
 
 	function push(value) {
 		if (stack.length === 1) {
@@ -40,28 +39,28 @@ module.exports = function (context) {
 	function popAndReport(node) {
 		if (!stack.pop()) {
 			context.report({
-				node: node,
-				message: 'The catch parameter should be named `' + name + '`.'
+				node,
+				message: `The catch parameter should be named \`${name}\`.`
 			});
 		}
 	}
 
 	return {
-		'CallExpression': function (node) {
+		'CallExpression': node => {
 			if (isLintablePromiseCatch(node)) {
-				var params = node.arguments[0].params;
+				const params = node.arguments[0].params;
 				push(params.length === 0 || params[0].name === name);
 			}
 		},
-		'CallExpression:exit': function (node) {
+		'CallExpression:exit': node => {
 			if (isLintablePromiseCatch(node)) {
 				popAndReport(node.arguments[0].params[0]);
 			}
 		},
-		'CatchClause': function (node) {
+		'CatchClause': node => {
 			push(node.param.name === name);
 		},
-		'CatchClause:exit': function (node) {
+		'CatchClause:exit': node => {
 			popAndReport(node.param);
 		}
 	};

rules/filename-case.js

@@ -1,29 +1,28 @@
 'use strict';
-var path = require('path');
-var camelCase = require('lodash.camelcase');
-var kebabCase = require('lodash.kebabcase');
-var snakeCase = require('lodash.snakecase');
-var upperfirst = require('lodash.upperfirst');
+const path = require('path');
+const camelCase = require('lodash.camelcase');
+const kebabCase = require('lodash.kebabcase');
+const snakeCase = require('lodash.snakecase');
+const upperfirst = require('lodash.upperfirst');
 
-var pascalCase = function (str) {
-	return upperfirst(camelCase(str));
-};
-
-var numberRegex = /(\d+)/;
-var PLACEHOLDER = '\uFFFF\uFFFF\uFFFF';
-var PLACEHOLDER_REGEX = new RegExp(PLACEHOLDER, 'i');
+const pascalCase = str => upperfirst(camelCase(str));
+const numberRegex = /(\d+)/;
+const PLACEHOLDER = '\uFFFF\uFFFF\uFFFF';
+const PLACEHOLDER_REGEX = new RegExp(PLACEHOLDER, 'i');
 
 function ignoreNumbers(fn) {
-	return function (string) {
-		var stack = [];
-		var execResult = numberRegex.exec(string);
+	return str => {
+		const stack = [];
+		let execResult = numberRegex.exec(str);
+
 		while (execResult) {
 			stack.push(execResult[0]);
-			string = string.replace(execResult[0], PLACEHOLDER);
-			execResult = numberRegex.exec(string);
+			str = str.replace(execResult[0], PLACEHOLDER);
+			execResult = numberRegex.exec(str);
 		}
 
-		var withCase = fn(string);
+		let withCase = fn(str);
+
 		while (stack.length > 0) {
 			withCase = withCase.replace(PLACEHOLDER_REGEX, stack.shift());
 		}
@@ -32,7 +31,7 @@ function ignoreNumbers(fn) {
 	};
 }
 
-var cases = {
+const cases = {
 	camelCase: {
 		fn: camelCase,
 		name: 'camel case'
@@ -58,35 +57,35 @@ function fixFilename(chosenCase, filename) {
 		.join('.');
 }
 
-var leadingUnserscoresRegex = /^(_+)(.*)$/;
+const leadingUnserscoresRegex = /^(_+)(.*)$/;
 function splitFilename(filename) {
-	var res = leadingUnserscoresRegex.exec(filename);
+	const res = leadingUnserscoresRegex.exec(filename);
 	return {
 		leading: (res && res[1]) || '',
 		trailing: (res && res[2]) || filename
 	};
 }
 
-module.exports = function (context) {
-	var chosenCase = cases[context.options[0].case || 'camelCase'];
-	var filenameWithExt = context.getFilename();
+module.exports = context => {
+	const chosenCase = cases[context.options[0].case || 'camelCase'];
+	const filenameWithExt = context.getFilename();
 
 	if (filenameWithExt === '<text>') {
 		return {};
 	}
 
 	return {
-		Program: function (node) {
-			var extension = path.extname(filenameWithExt);
-			var filename = path.basename(filenameWithExt, extension);
-			var splitName = splitFilename(filename);
-			var fixedFilename = fixFilename(chosenCase, splitName.trailing);
+		Program: node => {
+			const extension = path.extname(filenameWithExt);
+			const filename = path.basename(filenameWithExt, extension);
+			const splitName = splitFilename(filename);
+			const fixedFilename = fixFilename(chosenCase, splitName.trailing);
+			const renameFilename = splitName.leading + fixedFilename + extension;
 
 			if (fixedFilename !== splitName.trailing) {
 				context.report({
-					node: node,
-					message: 'Filename is not in ' + chosenCase.name +
-						'. Rename it to `' + splitName.leading + fixedFilename + extension + '`.'
+					node,
+					message: `Filename is not in ${chosenCase.name}. Rename it to \`${renameFilename}\`.`
 				});
 			}
 		}

rules/no-abusive-eslint-disable.js

@@ -1,30 +1,28 @@
 'use strict';
 
-var disableRegex = /^eslint-disable(-next-line|-line)?($|(\s+([\w-]+))?)/;
+const disableRegex = /^eslint-disable(-next-line|-line)?($|(\s+([\w-]+))?)/;
 
-module.exports = function (context) {
-	return {
-		Program: function (node) {
-			node.comments.forEach(function (comment) {
-				var value = comment.value.trim();
-				var res = disableRegex.exec(value);
+module.exports = context => ({
+	Program: node => {
+		node.comments.forEach(comment => {
+			const value = comment.value.trim();
+			const res = disableRegex.exec(value);
 
-				if (res && // It is a eslint-disable comment
-					!res[2] // but it did not specify any rules
-				) {
-					context.report({
-						// Can't set it at the given location as the warning
-						// will be ignored due to the disable comment
-						loc: {
-							line: 0,
-							column: 0
-						},
-						// So specify it in the message
-						message: 'Specify the rules you want to disable at line {{line}}:{{column}}',
-						data: comment.loc.start
-					});
-				}
-			});
-		}
-	};
-};
+			if (res && // It's a eslint-disable comment
+				!res[2] // but it did not specify any rules
+			) {
+				context.report({
+					// Can't set it at the given location as the warning
+					// will be ignored due to the disable comment
+					loc: {
+						line: 0,
+						column: 0
+					},
+					// So specify it in the message
+					message: 'Specify the rules you want to disable at line {{line}}:{{column}}',
+					data: comment.loc.start
+				});
+			}
+		});
+	}
+});

rules/no-process-exit.js

@@ -1,18 +1,18 @@
 'use strict';
-module.exports = function (context) {
-	var startsWithHashBang = context.getSourceCode().lines[0].indexOf('#!') === 0;
+module.exports = context => {
+	const startsWithHashBang = context.getSourceCode().lines[0].indexOf('#!') === 0;
 
 	if (startsWithHashBang) {
 		return {};
 	}
 
 	return {
-		CallExpression: function (node) {
-			var callee = node.callee;
+		CallExpression: node => {
+			const callee = node.callee;
 
 			if (callee.type === 'MemberExpression' && callee.object.name === 'process' && callee.property.name === 'exit') {
 				context.report({
-					node: node,
+					node,
 					message: 'Only use `process.exit()` in CLI apps. Throw an error instead.'
 				});
 			}

rules/throw-new-error.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var errorTypes = [
+const errorTypes = [
 	'Error',
 	'EvalError',
 	'RangeError',
@@ -10,21 +10,17 @@ var errorTypes = [
 	'URIError'
 ];
 
-module.exports = function (context) {
-	return {
-		ThrowStatement: function (node) {
-			var arg = node.argument;
-			var error = arg.callee;
+module.exports = context => ({
+	ThrowStatement: node => {
+		const arg = node.argument;
+		const error = arg.callee;
 
-			if (arg.type === 'CallExpression' && errorTypes.indexOf(error.name) !== -1) {
-				context.report({
-					node: node,
-					message: 'Use `new` when throwing an error.',
-					fix: function (fixer) {
-						return fixer.insertTextBefore(error, 'new ');
-					}
-				});
-			}
+		if (arg.type === 'CallExpression' && errorTypes.indexOf(error.name) !== -1) {
+			context.report({
+				node,
+				message: 'Use `new` when throwing an error.',
+				fix: fixer => fixer.insertTextBefore(error, 'new ')
+			});
 		}
-	};
-};
+	}
+});

test/catch-error-name.js

@@ -10,8 +10,8 @@ const ruleTester = avaRuleTester(test, {
 
 function testCase(code, name, error) {
 	return {
-		code: code,
-		options: name && [{name: name}],
+		code,
+		options: name && [{name}],
 		errors: error && [{ruleId: 'catch-error-name'}]
 	};
 }

test/filename-case.js

@@ -11,7 +11,7 @@ const ruleTester = avaRuleTester(test, {
 function testCase(filename, chosenCase, errorMessage) {
 	return {
 		code: 'foo()',
-		filename: filename,
+		filename,
 		options: [{case: chosenCase}],
 		errors: errorMessage && [{
 			ruleId: 'filename-case',