feat(compiler): change html parser to preserve comments

modules/angular2/src/compiler/html_ast.ts

@@ -23,10 +23,16 @@ export class HtmlElementAst implements HtmlAst {
   visit(visitor: HtmlAstVisitor, context: any): any { return visitor.visitElement(this, context); }
 }
 
+export class HtmlCommentAst implements HtmlAst {
+  constructor(public value: string, public sourceSpan: ParseSourceSpan) {}
+  visit(visitor: HtmlAstVisitor, context: any): any { return visitor.visitComment(this, context); }
+}
+
 export interface HtmlAstVisitor {
   visitElement(ast: HtmlElementAst, context: any): any;
   visitAttr(ast: HtmlAttrAst, context: any): any;
   visitText(ast: HtmlTextAst, context: any): any;
+  visitComment(ast: HtmlCommentAst, context: any): any;
 }
 
 export function htmlVisitAll(visitor: HtmlAstVisitor, asts: HtmlAst[], context: any = null): any[] {

modules/angular2/src/compiler/html_parser.ts

@@ -11,7 +11,7 @@ import {
 
 import {ListWrapper} from 'angular2/src/facade/collection';
 
-import {HtmlAst, HtmlAttrAst, HtmlTextAst, HtmlElementAst} from './html_ast';
+import {HtmlAst, HtmlAttrAst, HtmlTextAst, HtmlCommentAst, HtmlElementAst} from './html_ast';
 
 import {Injectable} from 'angular2/src/core/di';
 import {HtmlToken, HtmlTokenType, tokenizeHtml} from './html_lexer';
@@ -98,9 +98,11 @@ class TreeBuilder {
     this._advanceIf(HtmlTokenType.CDATA_END);
   }
 
-  private _consumeComment(startToken: HtmlToken) {
+  private _consumeComment(token: HtmlToken) {
-    this._advanceIf(HtmlTokenType.RAW_TEXT);
+    var text = this._advanceIf(HtmlTokenType.RAW_TEXT);
     this._advanceIf(HtmlTokenType.COMMENT_END);
+    var value = isPresent(text) ? text.parts[0].trim() : null;
+    this._addToParent(new HtmlCommentAst(value, token.sourceSpan))
   }
 
   private _consumeText(token: HtmlToken) {

modules/angular2/src/compiler/legacy_template.ts

@@ -8,7 +8,14 @@ import {
   isPresent
 } from 'angular2/src/facade/lang';
 
-import {HtmlAstVisitor, HtmlAttrAst, HtmlElementAst, HtmlTextAst, HtmlAst} from './html_ast';
+import {
+  HtmlAstVisitor,
+  HtmlAttrAst,
+  HtmlElementAst,
+  HtmlTextAst,
+  HtmlCommentAst,
+  HtmlAst
+} from './html_ast';
 import {HtmlParser, HtmlParseTreeResult} from './html_parser';
 
 import {dashCaseToCamelCase, camelCaseToDashCase} from './util';
@@ -37,6 +44,8 @@ export class LegacyHtmlAstTransformer implements HtmlAstVisitor {
 
   constructor(private dashCaseSelectors?: string[]) {}
 
+  visitComment(ast: HtmlCommentAst, context: any): any { return ast; }
+
   visitElement(ast: HtmlElementAst, context: any): HtmlElementAst {
     this.visitingTemplateEl = ast.name.toLowerCase() == 'template';
     let attrs = ast.attrs.map(attr => attr.visit(this, null));

modules/angular2/src/compiler/template_normalizer.ts

@@ -20,6 +20,7 @@ import {
   HtmlTextAst,
   HtmlAttrAst,
   HtmlAst,
+  HtmlCommentAst,
   htmlVisitAll
 } from './html_ast';
 import {HtmlParser} from './html_parser';
@@ -126,6 +127,7 @@ class TemplatePreparseVisitor implements HtmlAstVisitor {
     }
     return null;
   }
+  visitComment(ast: HtmlCommentAst, context: any): any { return null; }
   visitAttr(ast: HtmlAttrAst, context: any): any { return null; }
   visitText(ast: HtmlTextAst, context: any): any { return null; }
 }

modules/angular2/src/compiler/template_parser.ts

@@ -41,6 +41,7 @@ import {
   HtmlElementAst,
   HtmlAttrAst,
   HtmlTextAst,
+  HtmlCommentAst,
   htmlVisitAll
 } from './html_ast';
 
@@ -209,6 +210,8 @@ class TemplateParseVisitor implements HtmlAstVisitor {
     return new AttrAst(ast.name, ast.value, ast.sourceSpan);
   }
 
+  visitComment(ast: HtmlCommentAst, context: any): any { return null; }
+
   visitElement(element: HtmlElementAst, component: Component): any {
     var nodeName = element.name;
     var preparsedElement = preparseElement(element);
@@ -676,6 +679,7 @@ class NonBindableVisitor implements HtmlAstVisitor {
     return new ElementAst(ast.name, htmlVisitAll(this, ast.attrs), [], [], [], [], children,
                           ngContentIndex, ast.sourceSpan);
   }
+  visitComment(ast: HtmlCommentAst, context: any): any { return null; }
   visitAttr(ast: HtmlAttrAst, context: any): AttrAst {
     return new AttrAst(ast.name, ast.value, ast.sourceSpan);
   }

modules/angular2/test/compiler/html_parser_spec.ts

@@ -17,6 +17,7 @@ import {
   HtmlElementAst,
   HtmlAttrAst,
   HtmlTextAst,
+  HtmlCommentAst,
   htmlVisitAll
 } from 'angular2/src/compiler/html_ast';
 import {ParseError, ParseLocation, ParseSourceSpan} from 'angular2/src/compiler/parse_util';
@@ -233,9 +234,9 @@ export function main() {
       });
 
       describe('comments', () => {
-        it('should ignore comments', () => {
+        it('should preserve comments', () => {
           expect(humanizeDom(parser.parse('<!-- comment --><div></div>', 'TestComp')))
-              .toEqual([[HtmlElementAst, 'div', 0]]);
+              .toEqual([[HtmlCommentAst, 'comment', 0], [HtmlElementAst, 'div', 0]]);
         });
       });
 
@@ -362,6 +363,12 @@ class Humanizer implements HtmlAstVisitor {
     return null;
   }
 
+  visitComment(ast: HtmlCommentAst, context: any): any {
+    var res = this._appendContext(ast, [HtmlCommentAst, ast.value, this.elDepth]);
+    this.result.push(res);
+    return null;
+  }
+
   private _appendContext(ast: HtmlAst, input: any[]): any[] {
     if (!this.includeSourceSpan) return input;
     input.push(ast.sourceSpan.toString());