Minify Templates based on a white list

ember-cli-build.js

@@ -7,6 +7,13 @@ const EmberAddon = require('ember-cli/lib/broccoli/ember-addon');
 module.exports = function(defaults) {
   let app = new EmberAddon(defaults, {
     // Add options here
+    'ember-hbs-minifier': {
+      skip: {
+        elements: ['pre', 'address'],
+        classes: ['description'],
+        components: ['foo-bar']
+      }
+    }
   });
 
   /*

hbs-minifier-plugin.js

@@ -6,10 +6,13 @@ const stripWhiteSpace = Util.stripWhiteSpace;
 const isWhitespaceTextNode = Util.isWhitespaceTextNode;
 const hasLeadingOrTrailingWhiteSpace = Util.hasLeadingOrTrailingWhiteSpace;
 const stripNoMinifyBlocks = Util.stripNoMinifyBlocks;
+const canTrimBlockStatementContent = Util.canTrimBlockStatementContent;
+const canTrimElementNodeContent = Util.canTrimElementNodeContent;
+const assignDefaultValues = Util.assignDefaultValues;
 
-class HBSMinifierPlugin {
-
-  static createASTPlugin() {
+class BasePlugin {
+  static createASTPlugin(config) {
+    config = config || {};
     let preStack = [];
     let visitor = {
       TextNode(node) {
@@ -21,13 +24,14 @@ class HBSMinifierPlugin {
 
       BlockStatement: {
         enter(node) {
-          if (node.path.original === 'no-minify') {
-            preStack.push(true);
+          let canTrim = canTrimBlockStatementContent(node, config);
+          if (!canTrim) {
+            preStack.push(node);
           }
         },
 
         exit(node) {
-          if (node.path.original === 'no-minify') {
+          if (preStack[preStack.length - 1] === node) {
             preStack.pop();
           }
         },
@@ -52,13 +56,19 @@ class HBSMinifierPlugin {
 
         exit(node) {
           node.body = stripNoMinifyBlocks(node.body);
+
+          if (preStack[preStack.length - 1] === node) {
+            preStack.pop();
+          }
         },
       },
 
       ElementNode: {
         enter(node) {
-          if (node.tag === 'pre') {
-            preStack.push(true);
+          let canTrim = canTrimElementNodeContent(node, config);
+
+          if (!canTrim) {
+            preStack.push(node);
           }
 
           if (preStack.length !== 0) {
@@ -79,7 +89,7 @@ class HBSMinifierPlugin {
         exit(node) {
           node.children = stripNoMinifyBlocks(node.children);
 
-          if (node.tag === 'pre') {
+          if (preStack[preStack.length - 1] === node) {
             preStack.pop();
           }
         }
@@ -88,15 +98,26 @@ class HBSMinifierPlugin {
 
     return { name: 'hbs-minifier-plugin', visitor };
   }
-
-  transform(ast) {
-    let plugin = HBSMinifierPlugin.createASTPlugin();
-
-    this.syntax.traverse(ast, plugin.visitor);
-
-    return ast;
-  }
-
 }
 
-module.exports = HBSMinifierPlugin;
+module.exports = function(config) {
+  config = config || {};
+  config = assignDefaultValues(config);
+
+  return class HBSMinifierPlugin extends BasePlugin {
+
+    transform(ast) {
+      let startLoc = ast.loc ? ast.loc.start : {};
+      /*
+        checking for line and column to avoid registering the plugin for ProgramNode inside a BlockStatement.
+      */
+      if (startLoc.line !== 1 || startLoc.column !== 0) {
+        return ast;
+      }
+
+      let plugin = HBSMinifierPlugin.createASTPlugin(config);
+      this.syntax.traverse(ast, plugin.visitor);
+      return ast;
+    }
+  };
+};

hbs-minifier-plugin.test.js

@@ -1,9 +1,15 @@
 'use strict';
 
 /* eslint-env jest */
-
+const defaultConfig = {
+  skip: {
+    elements: ['pre', 'address'],
+    classes: ['description'],
+    components: ['foo-bar']
+  }
+};
 const glimmer = require('@glimmer/syntax');
-const HbsMinifierPlugin = require('./hbs-minifier-plugin');
+const HbsMinifierPlugin = require('./hbs-minifier-plugin')(defaultConfig);
 
 it('collapses whitespace into single space character', () => {
   assert(`{{foo}}  \n\n   \n{{bar}}`);
@@ -45,17 +51,73 @@ it('does not collapse whitespace inside of {{#no-minify}} tags in other tags', f
   assert(`<div>{{#no-minify}}  \n\n   \n{{/no-minify}}</div>`);
 });
 
-it('11. does not collapse multiple &nbsp; textNode into a single whitespace', function() {
+it('does not collapse multiple &nbsp; textNode into a single whitespace', function() {
   assert(`<span>1</span>&nbsp;&nbsp;<span>2</span>`);
 });
 
-it('12. does not collapse &nbsp; surrounding a text content into a single whitespace', function() {
+it('does not collapse &nbsp; surrounding a text content into a single whitespace', function() {
   assert(`<div>
   <span>    &nbsp;1&nbsp;   </span>
   <span> 2   </span>
 </div>`);
 });
 
+it('does not minify `tagNames` specified in .hbs-minifyrc.js', function() {
+  assert(`<address>
+  Box 564,
+  <b>
+    Disneyland
+  </b>
+  <br>
+  <u> USA </u>
+</address>`);
+});
+
+it('does not minify `classNames` specified in .hbs-minifyrc.js', function() {
+  assert(`<div class="description">
+  1
+  <span>
+    2
+  </span>
+</div>`);
+});
+
+it('does not minify `components` specified in .hbs-minifyrc.js', function() {
+  assert(`{{#foo-bar}}
+  <span>
+    yield content
+  </span>
+{{/foo-bar}}`);
+});
+
+it('minifies `tagNames` that are not specified in .hbs-minifyrc.js', function() {
+  assert(`<section>
+  Box 564,
+  <b>
+    Disneyland
+  </b>
+  <br>
+  <u> USA </u>
+</section>`);
+});
+
+it('minifies `classNames` that are not specified in .hbs-minifyrc.js', function() {
+  assert(`<div class="contact-details">
+  John Smith
+  <i>
+    (Entrepreneur)
+  </i>
+</div>`);
+});
+
+it('minifies `components` that are not specified in .hbs-minifyrc.js', function() {
+  assert(`{{#my-component}}
+  <span>
+    yield content
+  </span>
+{{/my-component}}`);
+});
+
 function assert(template) {
   let ast = process(template);
   expect(ast).toMatchSnapshot();
@@ -65,9 +127,12 @@ function assert(template) {
 }
 
 function process(template) {
+  let plugin = () => {
+    return HbsMinifierPlugin.createASTPlugin(defaultConfig.skip);
+  };
   return glimmer.preprocess(template, {
     plugins: {
-      ast: [HbsMinifierPlugin.createASTPlugin]
+      ast: [plugin]
     }
   });
 }

index.js

@@ -1,18 +1,30 @@
 /* eslint-env node */
 'use strict';
+let objectHash = require('object-hash');
 
 module.exports = {
   name: 'ember-hbs-minifier',
 
-  setupPreprocessorRegistry(type, registry) {
-    if (type === 'parent') {
-      let HbsMinifierPlugin = require('./hbs-minifier-plugin');
+  _setupPreprocessorRegistry(app) {
+    let registry = app.registry;
+    let options = app.options || {};
+    let config = options['ember-hbs-minifier'] || {};
 
-      registry.add('htmlbars-ast-plugin', {
-        name: 'hbs-minifier-plugin',
-        plugin: HbsMinifierPlugin,
-        baseDir() { return __dirname; }
-      });
-    }
+    let HbsMinifierPlugin = require('./hbs-minifier-plugin')(config.skip || {});
+    registry.add('htmlbars-ast-plugin', {
+      name: 'hbs-minifier-plugin',
+      plugin: HbsMinifierPlugin,
+      baseDir() { return __dirname; },
+      cacheKey() { return `ember-hbs-minifier-${objectHash.MD5(config)}`; }
+    });
   },
+
+  included(app) {
+    this._super.included.apply(this, arguments);
+    /*
+      Calling setupPreprocessorRegistry in included hook since app.options is not accessible
+      Refer PR: https://github.com/ember-cli/ember-cli/pull/7059
+    */
+    this._setupPreprocessorRegistry(app);
+  }
 };

package.json

@@ -50,6 +50,9 @@
     "jest": "^21.2.0",
     "loader.js": "^4.2.3"
   },
+  "dependencies": {
+    "object-hash": "1.2.0"
+  },
   "engines": {
     "node": ">= 4"
   },

tests/dummy/app/components/foo-bar.js

@@ -0,0 +1,6 @@
+import Ember from 'ember';
+import layout from '../templates/components/foo-bar';
+
+export default Ember.Component.extend({
+  layout
+});

tests/dummy/app/components/x-button.js

@@ -0,0 +1,6 @@
+import Ember from 'ember';
+import layout from '../templates/components/x-button';
+
+export default Ember.Component.extend({
+  layout
+});

tests/dummy/app/templates/components/foo-bar.hbs

@@ -0,0 +1,8 @@
+1
+<span>
+  2
+</span>
+<span>
+  3
+</span>
+{{yield}}

tests/dummy/app/templates/components/x-button.hbs

@@ -0,0 +1,2 @@
+save
+{{yield}}