Update project configuration

Author: jonathantneal

.appveyor.yml

@@ -0,0 +1,18 @@
+# https://www.appveyor.com/docs/appveyor-yml
+
+environment:
+  matrix:
+    - nodejs_version: 4
+
+version: "{build}"
+build: off
+deploy: off
+
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - npm install --ignore-scripts
+
+test_script:
+  - node --version
+  - npm --version
+  - cmd: "npm test"

.gitignore

@@ -1,10 +1,12 @@
 node_modules
+index.*.js
 package-lock.json
+*.log*
+*.result.css
 .*
 !.appveyor.yml
 !.editorconfig
 !.gitignore
+!.rollup.js
 !.tape.js
 !.travis.yml
-*.log*
-*.result.css

.rollup.js

@@ -0,0 +1,16 @@
+import babel from 'rollup-plugin-babel';
+
+export default {
+	input: 'index.js',
+	output: [
+		{ file: 'index.cjs.js', format: 'cjs' },
+		{ file: 'index.es.js', format: 'es' }
+	],
+	plugins: [
+		babel({
+			presets: [
+				['env', { modules: false, targets: { node: 4 } }]
+			]
+		})
+	]
+};

index.js

@@ -1,8 +1,5 @@
-'use strict';
-
-// external tooling
-const postcss   = require('postcss');
-const transform = require('postcss-nesting/lib/transform');
+import postcss from 'postcss';
+import nesting from 'postcss-nesting';
 
 // extend at-rule match
 const extendMatch = /^(extend)$/i;
@@ -11,13 +8,13 @@ const extendMatch = /^(extend)$/i;
 const functionalSelectorMatch = /(^|[^\w-])(%[_a-zA-Z]+[_a-zA-Z0-9-]*)([^\w-]|$)/i;
 
 // plugin
-module.exports = postcss.plugin('postcss-extend-rule', (rawopts) => {
+export default postcss.plugin('postcss-extend-rule', rawopts => {
 	// options ( onFunctionalSelector, onRecursiveExtend, onUnusedExtend)
 	const opts = Object(rawopts);
 
 	return (root, result) => {
 		// for each extend at-rule
-		root.walkAtRules(extendMatch, (extendAtRule) => {
+		root.walkAtRules(extendMatch, extendAtRule => {
 			// do not revisit visited extend at-rules
 			if (!extendAtRule.__extendAtRuleVisited) {
 				extendAtRule.__extendAtRuleVisited = true;
@@ -35,7 +32,7 @@ module.exports = postcss.plugin('postcss-extend-rule', (rawopts) => {
 
 					// transform any nesting at-rules
 					extendingRules.forEach(
-						(extendingRule) => {
+						extendingRule => {
 							transform(extendingRule);
 
 							extendingRule.walk(transform);
@@ -67,7 +64,7 @@ module.exports = postcss.plugin('postcss-extend-rule', (rawopts) => {
 			}
 		});
 
-		root.walkRules(functionalSelectorMatch, (functionalRule) => {
+		root.walkRules(functionalSelectorMatch, functionalRule => {
 			// manage encountered functional selectors
 			const functionalSelectorMessage = `Encountered functional selector "${functionalRule.selector}"`;
 
@@ -82,17 +79,25 @@ module.exports = postcss.plugin('postcss-extend-rule', (rawopts) => {
 	};
 });
 
+function transform(node) {
+	return nesting()({
+		walk(transformer) {
+			return transformer(node)
+		}
+	});
+}
+
 function getExtendingRules(selectorIdMatch, extendAtRule) {
 	// extending rules
 	const extendingRules = [];
 
 	// for each rule found from root of the extend at-rule with a matching selector identifier
-	extendAtRule.root().walkRules(selectorIdMatch, (matchingRule) => {
+	extendAtRule.root().walkRules(selectorIdMatch, matchingRule => {
 		// nesting selectors for the selectors matching the selector identifier
 		const nestingSelectors = matchingRule.selectors.filter(
-			(selector) => selectorIdMatch.test(selector)
+			selector => selectorIdMatch.test(selector)
 		).map(
-			(selector) => selector.replace(selectorIdMatch, '$1&$3')
+			selector => selector.replace(selectorIdMatch, '$1&$3')
 		).join(',');
 
 		// matching rule’s cloned nodes
@@ -127,7 +132,7 @@ function getExtendingRules(selectorIdMatch, extendAtRule) {
 function getSelectorIdMatch(selectorIds) {
 	// escape the contents of the selector id to avoid being parsed as regex
 	const escapedSelectorIds = postcss.list.comma(selectorIds).map(
-		(selectorId) => selectorId.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
+		selectorId => selectorId.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
 	).join('|');
 
 	// selector unattached to an existing selector

package.json

@@ -7,32 +7,40 @@
   "repository": "jonathantneal/postcss-extend-rule",
   "homepage": "https://github.com/jonathantneal/postcss-extend-rule#readme",
   "bugs": "https://github.com/jonathantneal/postcss-extend-rule/issues",
-  "main": "index.js",
+  "main": "index.cjs.js",
+  "module": "index.es.js",
   "files": [
-    "index.js"
+    "index.cjs.js",
+    "index.es.js"
   ],
   "scripts": {
-    "clean": "git clean -X -d -f",
-    "prepublish": "npm test",
+    "prepublishOnly": "npm test",
+    "pretest": "rollup -c .rollup.js --silent",
     "test": "echo 'Running tests...'; npm run test:js && npm run test:tape",
-    "test:js": "eslint *.js --cache --ignore-pattern .gitignore",
+    "test:js": "eslint *.js --cache --ignore-path .gitignore --quiet",
     "test:tape": "postcss-tape"
   },
   "engines": {
     "node": ">=4.0.0"
   },
   "dependencies": {
-    "postcss": "^6.0.11",
-    "postcss-nesting": "^4.2.1"
+    "postcss": "^6.0.22",
+    "postcss-nesting": "^5.0.0"
   },
   "devDependencies": {
-    "eslint": "^4.7.1",
-    "eslint-config-dev": "2.0.0",
-    "postcss-tape": "2.1.0",
-    "pre-commit": "^1.2.2"
+    "babel-core": "^6.26.3",
+    "babel-eslint": "^8.2.3",
+    "babel-preset-env": "^1.7.0",
+    "eslint": "^4.19.1",
+    "eslint-config-dev": "^2.0.0",
+    "postcss-tape": "^2.2.0",
+    "pre-commit": "^1.2.2",
+    "rollup": "^0.59.4",
+    "rollup-plugin-babel": "^3.0.4"
   },
   "eslintConfig": {
-    "extends": "dev"
+    "extends": "dev",
+    "parser": "babel-eslint"
   },
   "keywords": [
     "postcss",