diff --git a/modules/angular2/src/dom/browser_adapter.dart b/modules/angular2/src/dom/browser_adapter.dart
index ddc5dab47b..1be8cbaf4e 100644
--- a/modules/angular2/src/dom/browser_adapter.dart
+++ b/modules/angular2/src/dom/browser_adapter.dart
@@ -188,8 +188,8 @@ class BrowserDomAdapter extends DomAdapter {
   Node importIntoDoc(Node node) {
     return document.importNode(node, true);
   }
-  isPageRule(CssRule rule) => rule is CssPageRule;
-  isStyleRule(CssRule rule) => rule is CssStyleRule;
-  isMediaRule(CssRule rule) => rule is CssMediaRule;
-  isKeyframesRule(CssRule rule) => rule is CssKeyframesRule;
+  bool isPageRule(CssRule rule) => rule is CssPageRule;
+  bool isStyleRule(CssRule rule) => rule is CssStyleRule;
+  bool isMediaRule(CssRule rule) => rule is CssMediaRule;
+  bool isKeyframesRule(CssRule rule) => rule is CssKeyframesRule;
 }
diff --git a/modules/angular2/src/dom/browser_adapter.es6 b/modules/angular2/src/dom/browser_adapter.es6
index 81cf7d9790..144e6de256 100644
--- a/modules/angular2/src/dom/browser_adapter.es6
+++ b/modules/angular2/src/dom/browser_adapter.es6
@@ -17,7 +17,7 @@ export class BrowserDomAdapter extends DomAdapter {
     return _attrToPropMap;
   }
 
-  query(selector) {
+  query(selector:string) {
     return document.querySelector(selector);
   }
   querySelector(el, selector:string):Node {
@@ -246,16 +246,16 @@ export class BrowserDomAdapter extends DomAdapter {
     }
     return result;
   }
-  isPageRule(rule) {
+  isPageRule(rule): boolean {
     return rule.type === CSSRule.PAGE_RULE;
   }
-  isStyleRule(rule) {
+  isStyleRule(rule): boolean {
     return rule.type === CSSRule.STYLE_RULE;
   }
-  isMediaRule(rule) {
+  isMediaRule(rule): boolean {
     return rule.type === CSSRule.MEDIA_RULE;
   }
-  isKeyframesRule(rule) {
+  isKeyframesRule(rule): boolean {
     return rule.type === CSSRule.KEYFRAMES_RULE;
   }
 }
diff --git a/modules/angular2/src/dom/dom_adapter.js b/modules/angular2/src/dom/dom_adapter.js
index 70e1a2668c..c43c4abe40 100644
--- a/modules/angular2/src/dom/dom_adapter.js
+++ b/modules/angular2/src/dom/dom_adapter.js
@@ -27,7 +27,7 @@ export class DomAdapter {
   parse(templateHtml:string) {
     throw _abstract();
   }
-  query(selector) {
+  query(selector:string) {
     throw _abstract();
   }
   querySelector(el, selector:string) {
@@ -222,16 +222,16 @@ export class DomAdapter {
   importIntoDoc(node) {
     throw _abstract();
   }
-  isPageRule(rule) {
+  isPageRule(rule): boolean {
     throw _abstract();
   }
-  isStyleRule(rule) {
+  isStyleRule(rule): boolean {
     throw _abstract();
   }
-  isMediaRule(rule) {
+  isMediaRule(rule): boolean {
     throw _abstract();
   }
-  isKeyframesRule(rule) {
+  isKeyframesRule(rule): boolean {
     throw _abstract();
   }
 }
diff --git a/modules/angular2/src/dom/html5lib_adapter.dart b/modules/angular2/src/dom/html5lib_adapter.dart
index 0e36f51315..e37ffe4678 100644
--- a/modules/angular2/src/dom/html5lib_adapter.dart
+++ b/modules/angular2/src/dom/html5lib_adapter.dart
@@ -49,7 +49,7 @@ class Html5LibDomAdapter implements DomAdapter {
   content(TemplateElement node) {
     throw 'not implemented';
   }
-  
+
   firstChild(el) => el is NodeList
     ? el.first
     : el.firstChild;
@@ -166,7 +166,7 @@ class Html5LibDomAdapter implements DomAdapter {
   getStyle(element, String stylename) {
     throw 'not implemented';
   }
-  
+
   String tagName(element) => element.localName;
 
   attributeMap(element) => element.attributes;
@@ -205,7 +205,7 @@ class Html5LibDomAdapter implements DomAdapter {
   bool isCommentNode(node) {
     throw 'not implemented';
   }
-  
+
   bool isElementNode(node) => node is Element;
 
   bool hasShadowRoot(node) {
@@ -214,16 +214,16 @@ class Html5LibDomAdapter implements DomAdapter {
   importIntoDoc(node) {
     throw 'not implemented';
   }
-  isPageRule(rule) {
+  bool isPageRule(rule) {
     throw 'not implemented';
   }
-  isStyleRule(rule) {
+  bool isStyleRule(rule) {
     throw 'not implemented';
   }
-  isMediaRule(rule) {
+  bool isMediaRule(rule) {
     throw 'not implemented';
   }
-  isKeyframesRule(rule) {
+  bool isKeyframesRule(rule) {
     throw 'not implemented';
   }
 }