Improvements

.eslintrc

@@ -1,3 +1,9 @@
 {
-  "extends": "airbnb-base"
+  "extends": "airbnb-base",
+  "env": {
+    "node": true
+  },
+  "rules": {
+    "no-param-reassign": "off"
+  }
 }

.tool-versions

@@ -1 +1 @@
-nodejs 9.1.0
+nodejs 9.2.0

index.js

@@ -1,3 +1 @@
-'use strict';
-
 module.exports = require('./lib/plugin');

lib/plugin.js

@@ -1,25 +1,32 @@
-const Hashids = require('hashids');
 const posthtml = require('posthtml');
 const postcssSafeParser = require('postcss-safe-parser');
 const postcssSelectorParser = require('postcss-selector-parser');
+const cssNameGenerator = require('css-class-generator');
 
 const { version } = require('../package');
 
-const ALPHABET = 'abcdefghijklmnopqrstuvwxyz';
-
 class HTMLUglify {
-  constructor(config = {}) {
-    const salt = config.salt || 'use the force harry';
-    this.hashids = new Hashids(salt, 0, ALPHABET);
-    this.whitelist = config.whitelist || [];
+  constructor({ whitelist = [] } = {}) {
     this.version = version;
+    this.whitelist = whitelist;
+    this.generators = {
+      id: cssNameGenerator(),
+      class: cssNameGenerator(),
+    };
   }
 
-  checkForStandardPointer(type, value, lookups) {
+  static insertLookup(type, value, pointer, lookups) {
+    if (!lookups[type]) {
+      lookups[type] = {};
+    }
+    lookups[type][value] = pointer;
+  }
+
+  static checkForStandardPointer(type, value, lookups) {
     return lookups[type] && lookups[type][value];
   }
 
-  checkForAttributePointer(type, value, lookups) {
+  static checkForAttributePointer(type, value, lookups) {
     const typeLookups = lookups[type] || {};
     const keys = Object.keys(typeLookups);
     let pointer;
@@ -35,49 +42,33 @@ class HTMLUglify {
     return pointer;
   }
 
-  generatePointer(lookups) {
-    const idCount = Object.keys(lookups['id'] || {}).length;
-    const classCount = Object.keys(lookups['class'] || {}).length;
-    const counter = idCount + classCount;
+  generatePointer(type) {
+    const { value } = this.generators[type].next();
+    if (this.isWhitelisted(type, value)) {
+      return this.generatePointer(type);
+    }
 
-    return this.hashids.encode(counter);
+    return value;
   }
 
   pointer(type, value, lookups) {
-    return this.checkForStandardPointer(type, value, lookups) ||
-      this.checkForAttributePointer(type, value, lookups) ||
-      this.generatePointer(lookups);
-  }
-
-  insertLookup(type, value, pointer, lookups) {
-    if (!lookups[type]) {
-      lookups[type] = {};
-    }
-    lookups[type][value] = pointer;
+    return this.constructor.checkForStandardPointer(type, value, lookups) ||
+      this.constructor.checkForAttributePointer(type, value, lookups) ||
+      this.generatePointer(type);
   }
 
   createLookup(type, value, lookups) {
     let pointer;
     if (value && !this.isWhitelisted(type, value)) {
       pointer = this.pointer(type, value, lookups);
-      this.insertLookup(type, value, pointer, lookups);
+      this.constructor.insertLookup(type, value, pointer, lookups);
     }
     return pointer;
   }
 
   isWhitelisted(type, value) {
-    switch (type) {
-      case 'class':
-        value = '.' + value;
-        break;
-      case 'id':
-        value = '#' + value;
-        break;
-      default:
-        break;
-    }
-
-    return this.whitelist.indexOf(value) >= 0;
+    const prefix = type === 'id' ? '#' : '.';
+    return this.whitelist.includes(`${prefix}${value}`);
   }
 
   pointerizeClass(node, lookups) {
@@ -127,7 +118,7 @@ class HTMLUglify {
           });
 
           rule.selector = String(selectors);
-        }).process(rule.selector);
+        }).processSync(rule.selector);
       }
     });
   }
@@ -156,28 +147,29 @@ class HTMLUglify {
       if (node.tag === 'style' && node.content) {
         const ast = postcssSafeParser([].concat(node.content).join(''));
         this.processRules(ast.nodes, lookups);
-        node.content = ast.toString();
+        node.content = [ast.toString()];
       }
       return node;
     });
   }
 
   process(tree) {
     const lookups = {};
+    this.generators.id = cssNameGenerator();
+    this.generators.class = cssNameGenerator();
     tree = this.rewriteStyles(tree, lookups);
     tree = this.rewriteElements(tree, lookups);
     return tree;
   }
 }
 
 module.exports = (options) => {
-  return (tree) => {
-    return new HTMLUglify(options).process(tree);
-  }
+  const plugin = new HTMLUglify(options);
+  return tree => plugin.process(tree);
 };
 
 module.exports.HTMLUglify = HTMLUglify;
 
-module.exports.process = (html, options) => {
+module.exports.process = (html, options) => { // eslint-disable-line arrow-body-style
   return posthtml().use(module.exports(options)).process(html, { sync: true });
 };