chore: add more type annotations

modules/angular2/src/change_detection/parser/ast.js

@@ -6,7 +6,7 @@ export class AST {
     throw new BaseException("Not supported");
   }
 
-  get isAssignable() {
+  get isAssignable():boolean {
     return false;
   }
 
@@ -113,7 +113,7 @@ export class AccessMember extends AST {
     }
   }
 
-  get isAssignable() {
+  get isAssignable():boolean {
     return true;
   }
 
@@ -148,7 +148,7 @@ export class KeyedAccess extends AST {
     return obj[key];
   }
 
-  get isAssignable() {
+  get isAssignable():boolean {
     return true;
   }
 
@@ -397,7 +397,7 @@ export class ASTWithSource extends AST {
     return this.ast.eval(context, locals);
   }
 
-  get isAssignable() {
+  get isAssignable():boolean {
     return this.ast.isAssignable;
   }
 

modules/angular2/src/change_detection/parser/locals.js

@@ -34,7 +34,7 @@ export class Locals {
     throw new BaseException(`Cannot find '${name}'`);
   }
 
-  set(name:string, value) {
+  set(name:string, value):void {
     // TODO(rado): consider removing this check if we can guarantee this is not
     // exposed to the public API.
     // TODO: vsavkin maybe it should check only the local map
@@ -45,7 +45,7 @@ export class Locals {
     }
   }
 
-  clearValues() {
+  clearValues():void {
     MapWrapper.clearValues(this.current);
   }
 }

modules/angular2/src/core/annotations/view.js

@@ -38,14 +38,14 @@ export class View {
    *
    * NOTE: either `templateURL` or `template` should be used, but not both.
    */
-  templateUrl:any; //string;
+  templateUrl:string;
 
   /**
    * Specifies an inline template for an angular component.
    *
    * NOTE: either `templateURL` or `template` should be used, but not both.
    */
-  template:any; //string;
+  template:string;
 
   /**
    * Specifies a list of directives that can be used within a template.
@@ -69,7 +69,7 @@ export class View {
    * }
    * ```
    */
-  directives:any; //List<Type>;
+  directives:List<Type>;
 
   /**
    * Specify a custom renderer for this View.

modules/angular2/src/core/application_tokens.js

@@ -1,7 +1,7 @@
 import {OpaqueToken} from 'angular2/di';
 
-export var appComponentRefToken = new OpaqueToken('ComponentRef');
+export var appComponentRefToken:OpaqueToken = new OpaqueToken('ComponentRef');
-export var appChangeDetectorToken = new OpaqueToken('AppChangeDetector');
+export var appChangeDetectorToken:OpaqueToken = new OpaqueToken('AppChangeDetector');
-export var appElementToken = new OpaqueToken('AppElement');
+export var appElementToken:OpaqueToken = new OpaqueToken('AppElement');
-export var appComponentAnnotatedTypeToken = new OpaqueToken('AppComponentAnnotatedType');
+export var appComponentAnnotatedTypeToken:OpaqueToken = new OpaqueToken('AppComponentAnnotatedType');
-export var appDocumentToken = new OpaqueToken('AppDocument');
+export var appDocumentToken:OpaqueToken = new OpaqueToken('AppDocument');

modules/angular2/src/core/compiler/compiler.js

@@ -26,7 +26,7 @@ export class CompilerCache {
     this._cache = MapWrapper.create();
   }
 
-  set(component:Type, protoView:AppProtoView) {
+  set(component:Type, protoView:AppProtoView):void {
     MapWrapper.set(this._cache, component, protoView);
   }
 
@@ -35,7 +35,7 @@ export class CompilerCache {
     return normalizeBlank(result);
   }
 
-  clear() {
+  clear():void {
     MapWrapper.clear(this._cache);
   }
 }
@@ -73,7 +73,7 @@ export class Compiler {
     this._protoViewFactory = protoViewFactory;
   }
 
-  _bindDirective(directiveTypeOrBinding) {
+  _bindDirective(directiveTypeOrBinding):DirectiveBinding {
     if (directiveTypeOrBinding instanceof DirectiveBinding) {
       return directiveTypeOrBinding;
     }
@@ -190,7 +190,7 @@ export class Compiler {
     }
   }
 
-  _buildRenderTemplate(component, view, directives) {
+  _buildRenderTemplate(component, view, directives): renderApi.ViewDefinition {
     var componentUrl = this._urlResolver.resolve(
         this._appUrl, this._componentUrlMapper.getUrl(component)
     );
@@ -211,7 +211,7 @@ export class Compiler {
     });
   }
 
-  static buildRenderDirective(directiveBinding) {
+  static buildRenderDirective(directiveBinding):renderApi.DirectiveMetadata {
     var ann = directiveBinding.annotation;
     var renderType;
     var compileChildren = true;
@@ -254,7 +254,7 @@ export class Compiler {
     return directives;
   }
 
-  _flattenList(tree:List<any>, out:List<Type>) {
+  _flattenList(tree:List<any>, out:List<Type>):void {
     for (var i = 0; i < tree.length; i++) {
       var item = tree[i];
       if (ListWrapper.isList(item)) {

modules/angular2/src/core/compiler/dynamic_component_loader.js

@@ -123,7 +123,7 @@ export class DynamicComponentLoader {
   }
 
   /** Asserts that the type being dynamically instantiated is a Component. */
-  _assertTypeIsComponent(type:Type) {
+  _assertTypeIsComponent(type:Type):void {
     var annotation = this._directiveMetadataReader.read(type).annotation;
     if (!(annotation instanceof Component)) {
       throw new BaseException(`Could not load '${stringify(type)}' because it is not a component.`);

modules/angular2/src/core/compiler/element_injector.js

@@ -59,7 +59,7 @@ class StaticKeys {
     this.elementRefId = Key.get(ElementRef).id;
   }
 
-  static instance() {
+  static instance():StaticKeys {
     if (isBlank(_staticKeys)) _staticKeys = new StaticKeys();
     return _staticKeys;
   }
@@ -77,17 +77,17 @@ export class TreeNode {
     if (isPresent(parent)) parent.addChild(this);
   }
 
-  _assertConsistency() {
+  _assertConsistency():void {
     this._assertHeadBeforeTail();
     this._assertTailReachable();
     this._assertPresentInParentList();
   }
 
-  _assertHeadBeforeTail() {
+  _assertHeadBeforeTail():void {
     if (isBlank(this._tail) && isPresent(this._head)) throw new BaseException('null tail but non-null head');
   }
 
-  _assertTailReachable() {
+  _assertTailReachable():void {
     if (isBlank(this._tail)) return;
     if (isPresent(this._tail._next)) throw new BaseException('node after tail');
     var p = this._head;
@@ -95,7 +95,7 @@ export class TreeNode {
     if (isBlank(p) && isPresent(this._tail)) throw new BaseException('tail not reachable.')
   }
 
-  _assertPresentInParentList() {
+  _assertPresentInParentList():void {
     var p = this._parent;
     if (isBlank(p)) {
       return;
@@ -108,7 +108,7 @@ export class TreeNode {
   /**
    * Adds a child to the parent node. The child MUST NOT be a part of a tree.
    */
-  addChild(child:TreeNode) {
+  addChild(child:TreeNode):void {
     if (isPresent(this._tail)) {
       this._tail._next = child;
       this._tail = child;
@@ -124,7 +124,7 @@ export class TreeNode {
    * Adds a child to the parent node after a given sibling.
    * The child MUST NOT be a part of a tree and the sibling must be present.
    */
-  addChildAfter(child:TreeNode, prevSibling:TreeNode) {
+  addChildAfter(child:TreeNode, prevSibling:TreeNode):void {
     this._assertConsistency();
     if (isBlank(prevSibling)) {
       var prevHead = this._head;
@@ -146,7 +146,7 @@ export class TreeNode {
   /**
    * Detaches a node from the parent's tree.
    */
-  remove() {
+  remove():void {
     this._assertConsistency();
     if (isBlank(this.parent)) return;
     var nextSibling = this._next;
@@ -209,7 +209,7 @@ export class DirectiveDependency extends Dependency {
     this._verify();
   }
 
-  _verify() {
+  _verify():void {
     var count = 0;
     if (isPresent(this.propSetterName)) count++;
     if (isPresent(this.queryDirective)) count++;

modules/angular2/src/core/compiler/ng_element.js

@@ -28,7 +28,7 @@ export class NgElement {
     return domViewRef.delegate.boundElements[this._boundElementIndex];
   }
 
-  getAttribute(name:string) {
+  getAttribute(name:string):string {
     return normalizeBlank(DOM.getAttribute(this.domElement, name));
   }
 }

modules/angular2/src/core/compiler/view.js

@@ -75,7 +75,7 @@ export class AppView {
     this.componentChildViews = componentChildViews;
   }
 
-  getOrCreateViewContainer(boundElementIndex:number) {
+  getOrCreateViewContainer(boundElementIndex:number):ViewContainer {
     var viewContainer = this.viewContainers[boundElementIndex];
     if (isBlank(viewContainer)) {
       viewContainer = new ViewContainer(this, this.proto.elementBinders[boundElementIndex].nestedProtoView, this.elementInjectors[boundElementIndex]);
@@ -84,7 +84,7 @@ export class AppView {
     return viewContainer;
   }
 
-  setLocal(contextName: string, value) {
+  setLocal(contextName: string, value):void {
     if (!this.hydrated()) throw new BaseException('Cannot set locals on dehydrated view.');
     if (!MapWrapper.contains(this.proto.variableBindings, contextName)) {
       return;
@@ -93,7 +93,7 @@ export class AppView {
     this.locals.set(templateName, value);
   }
 
-  hydrated() {
+  hydrated():boolean {
     return isPresent(this.context);
   }
 
@@ -106,14 +106,14 @@ export class AppView {
    * @param {*} eventObj
    * @param {int} binderIndex
    */
-  triggerEventHandlers(eventName: string, eventObj, binderIndex: int) {
+  triggerEventHandlers(eventName: string, eventObj, binderIndex: int): void {
     var locals = MapWrapper.create();
     MapWrapper.set(locals, '$event', eventObj);
     this.dispatchEvent(binderIndex, eventName, locals);
   }
 
   // dispatch to element injector or text nodes based on context
-  notifyOnBinding(b:BindingRecord, currentValue:any) {
+  notifyOnBinding(b:BindingRecord, currentValue:any): void {
     if (b.isElement()) {
       this.renderer.setElementProperty(
         this.render, b.elementIndex, b.propertyName, currentValue
@@ -199,7 +199,7 @@ export class AppProtoView {
   //TODO: Tobias or Victor. Moving it into the constructor.
   // this work should be done the constructor of AppProtoView once we separate
   // AppProtoView and ProtoViewBuilder
-  getVariableBindings() {
+  getVariableBindings(): List {
     if (isPresent(this._variableBindings)) {
       return this._variableBindings;
     }
@@ -217,7 +217,7 @@ export class AppProtoView {
   //TODO: Tobias or Victor. Moving it into the constructor.
   // this work should be done the constructor of ProtoView once we separate
   // AppProtoView and ProtoViewBuilder
-  getdirectiveRecords() {
+  getdirectiveRecords(): List {
     if (isPresent(this._directiveRecords)) {
       return this._directiveRecords;
     }
@@ -236,7 +236,7 @@ export class AppProtoView {
     return this._directiveRecords;
   }
 
-  bindVariable(contextName:string, templateName:string) {
+  bindVariable(contextName:string, templateName:string): void {
     MapWrapper.set(this.variableBindings, contextName, templateName);
     MapWrapper.set(this.protoLocals, templateName, null);
   }
@@ -252,7 +252,7 @@ export class AppProtoView {
   /**
    * Adds a text node binding for the last created ElementBinder via bindElement
    */
-  bindTextNode(expression:AST) {
+  bindTextNode(expression:AST):void {
     var textNodeIndex = this.textNodesWithBindingCount++;
     var b = BindingRecord.createForTextNode(expression, textNodeIndex);
     ListWrapper.push(this.bindings, b);
@@ -261,7 +261,7 @@ export class AppProtoView {
   /**
    * Adds an element property binding for the last created ElementBinder via bindElement
    */
-  bindElementProperty(expression:AST, setterName:string) {
+  bindElementProperty(expression:AST, setterName:string):void {
     var elementIndex = this.elementBinders.length-1;
     var b = BindingRecord.createForElement(expression, elementIndex, setterName);
     ListWrapper.push(this.bindings, b);
@@ -280,7 +280,7 @@ export class AppProtoView {
    * @param {int} directiveIndex The directive index in the binder or -1 when the event is not bound
    *                             to a directive
    */
-  bindEvent(eventBindings: List<renderApi.EventBinding>, directiveIndex: int = -1) {
+  bindEvent(eventBindings: List<renderApi.EventBinding>, directiveIndex: int = -1): void {
     var elBinder = this.elementBinders[this.elementBinders.length - 1];
     var events = elBinder.hostListeners;
     if (isBlank(events)) {
@@ -306,7 +306,7 @@ export class AppProtoView {
     directiveIndex:number,
     expression:AST,
     setterName:string,
-    setter:SetterFn) {
+    setter:SetterFn): void {
 
     var elementIndex = this.elementBinders.length-1;
     var directiveRecord = this._getDirectiveRecord(elementIndex, directiveIndex);
@@ -314,7 +314,7 @@ export class AppProtoView {
     ListWrapper.push(this.bindings, b);
   }
 
-  _getDirectiveRecord(elementInjectorIndex:number, directiveIndex:number) {
+  _getDirectiveRecord(elementInjectorIndex:number, directiveIndex:number): DirectiveRecord {
     var id = elementInjectorIndex * 100 + directiveIndex;
     var protoElementInjector = this.elementBinders[elementInjectorIndex].protoElementInjector;
 

modules/angular2/src/core/compiler/view_container.js

@@ -27,17 +27,17 @@ export class ViewContainer {
     this._views = [];
   }
 
-  getRender() {
+  getRender():ViewContainerRef {
     return new ViewContainerRef(this.parentView.render, this.elementInjector.getBoundElementIndex());
   }
 
-  internalClearWithoutRender() {
+  internalClearWithoutRender():void {
     for (var i = this._views.length - 1; i >= 0; i--) {
       this._detachInjectors(i);
     }
   }
 
-  clear() {
+  clear():void {
     for (var i = this._views.length - 1; i >= 0; i--) {
       this.remove(i);
     }
@@ -47,22 +47,22 @@ export class ViewContainer {
     return this._views[index];
   }
 
-  get length() {
+  get length() /* :int */ {
     return this._views.length;
   }
 
-  _siblingInjectorToLinkAfter(index: number) {
+  _siblingInjectorToLinkAfter(index: number):eiModule.ElementInjector {
     if (index == 0) return null;
     return ListWrapper.last(this._views[index - 1].rootElementInjectors)
   }
 
-  hydrated() {
+  hydrated():boolean {
     return this.parentView.hydrated();
   }
 
   // TODO(rado): profile and decide whether bounds checks should be added
   // to the methods below.
-  create(atIndex=-1, protoView:viewModule.AppProtoView = null, injector:Injector = null): viewModule.AppView {
+  create(atIndex:number=-1, protoView:viewModule.AppProtoView = null, injector:Injector = null): viewModule.AppView {
     if (atIndex == -1) atIndex = this._views.length;
     if (!this.hydrated()) throw new BaseException(
         'Cannot create views on a dehydrated ViewContainer');
@@ -77,7 +77,7 @@ export class ViewContainer {
     return newView;
   }
 
-  insert(view, atIndex=-1): viewModule.AppView {
+  insert(view:viewModule.AppView, atIndex:number=-1): viewModule.AppView {
     if (atIndex == -1) atIndex = this._views.length;
     this._insertInjectors(view, atIndex);
     this.parentView.changeDetector.addChild(view.changeDetector);
@@ -85,7 +85,7 @@ export class ViewContainer {
     return view;
   }
 
-  _insertInjectors(view, atIndex): viewModule.AppView {
+  _insertInjectors(view:viewModule.AppView, atIndex:number): viewModule.AppView {
     ListWrapper.insert(this._views, atIndex, view);
     this._linkElementInjectors(this._siblingInjectorToLinkAfter(atIndex), view);
 
@@ -96,7 +96,7 @@ export class ViewContainer {
     return ListWrapper.indexOf(this._views, view);
   }
 
-  remove(atIndex=-1) {
+  remove(atIndex:number=-1):void {
     if (atIndex == -1) atIndex = this._views.length - 1;
     var view = this._views[atIndex];
     // opposite order as in create
@@ -110,7 +110,7 @@ export class ViewContainer {
    * The method can be used together with insert to implement a view move, i.e.
    * moving the dom nodes while the directives in the view stay intact.
    */
-  detach(atIndex=-1): viewModule.AppView {
+  detach(atIndex:number=-1): viewModule.AppView {
     if (atIndex == -1) atIndex = this._views.length - 1;
     var detachedView = this._detachInjectors(atIndex);
     detachedView.changeDetector.remove();
@@ -118,20 +118,20 @@ export class ViewContainer {
     return detachedView;
   }
 
-  _detachInjectors(atIndex): viewModule.AppView {
+  _detachInjectors(atIndex:number): viewModule.AppView {
     var detachedView = this.get(atIndex);
     ListWrapper.removeAt(this._views, atIndex);
     this._unlinkElementInjectors(detachedView);
     return detachedView;
   }
 
-  _linkElementInjectors(sibling, view) {
+  _linkElementInjectors(sibling, view:viewModule.AppView):void {
     for (var i = view.rootElementInjectors.length - 1; i >= 0; i--) {
       view.rootElementInjectors[i].linkAfter(this.elementInjector, sibling);
     }
   }
 
-  _unlinkElementInjectors(view) {
+  _unlinkElementInjectors(view:viewModule.AppView):void {
     for (var i = 0; i < view.rootElementInjectors.length; ++i) {
       view.rootElementInjectors[i].unlink();
     }

modules/angular2/src/di/exceptions.js

@@ -1,7 +1,7 @@
 import {ListWrapper, List} from 'angular2/src/facade/collection';
 import {stringify} from 'angular2/src/facade/lang';
 
-function findFirstClosedCycle(keys:List) {
+function findFirstClosedCycle(keys:List):List {
   var res = [];
   for(var i = 0; i < keys.length; ++i) {
     if (ListWrapper.contains(res, keys[i])) {
@@ -14,7 +14,7 @@ function findFirstClosedCycle(keys:List) {
   return res;
 }
 
-function constructResolvingPath(keys:List) {
+function constructResolvingPath(keys:List):string {
   if (keys.length > 1) {
     var reversed = findFirstClosedCycle(ListWrapper.reversed(keys));
     var tokenStrs = ListWrapper.map(reversed, (k) => stringify(k.token));
@@ -43,12 +43,12 @@ export class AbstractBindingError extends Error {
   }
 
   // TODO(tbosch): Can't do key:Key as this results in a circular dependency!
-  addKey(key) {
+  addKey(key):void {
     ListWrapper.push(this.keys, key);
     this.message = this.constructResolvingMessage(this.keys);
   }
 
-  toString() {
+  toString():string {
     return this.message;
   }
 }
@@ -166,7 +166,7 @@ export class InvalidBindingError extends Error {
     this.message = `Invalid binding ${binding}`;
   }
 
-  toString() {
+  toString():string {
     return this.message;
   }
 }
@@ -187,7 +187,7 @@ export class NoAnnotationError extends Error {
       ` Make sure they all have valid type or annotations.`;
   }
 
-  toString() {
+  toString():string {
     return this.message;
   }
 }

modules/angular2/src/di/injector.js

@@ -97,7 +97,7 @@ export class Injector {
    * bindings.
    * @param `defaultBindings` Setting to true will auto-create bindings.
    */
-  static resolveAndCreate(bindings:List/*<ResolvedBinding|Binding|Type|List>*/, {defaultBindings=false}={}) {
+  static resolveAndCreate(bindings:List/*<ResolvedBinding|Binding|Type|List>*/, {defaultBindings=false}={}): Injector {
     return new Injector(Injector.resolve(bindings), null, defaultBindings);
   }
 
@@ -108,7 +108,7 @@ export class Injector {
    * @param `bindings` A sparse list of {@link ResolvedBinding}s. See `resolve` for the {@link Injector}.
    * @param `defaultBindings` Setting to true will auto-create bindings.
    */
-  static fromResolvedBindings(bindings:List<ResolvedBinding>, {defaultBindings=false}={}) {
+  static fromResolvedBindings(bindings:List<ResolvedBinding>, {defaultBindings=false}={}): Injector {
     return new Injector(bindings, null, defaultBindings);
   }
 
@@ -133,7 +133,6 @@ export class Injector {
    * @returns an instance represented by the token. Throws if not found.
    */
   get(token) {
-
     return this._getByKey(Key.get(token), false, false, false);
   }
 
@@ -227,7 +226,7 @@ export class Injector {
     return ListWrapper.get(this._instances, key.id);
   }
 
-  _setInstance(key:Key, obj) {
+  _setInstance(key:Key, obj):void {
     ListWrapper.set(this._instances, key.id, obj);
   }
 
@@ -243,11 +242,11 @@ export class Injector {
     }
   }
 
-  _markAsConstructing(key:Key) {
+  _markAsConstructing(key:Key):void {
     this._setInstance(key, _constructing);
   }
 
-  _clear(key:Key) {
+  _clear(key:Key):void {
     this._setInstance(key, null);
   }
 }
@@ -325,7 +324,7 @@ class _AsyncInjectorStrategy {
     }
   }
 
-  instantiate(key:Key) {
+  instantiate(key:Key) /* Promise?? */ {
     var binding = this.injector._getBinding(key);
     if (isBlank(binding)) return _notFound;
 
@@ -395,7 +394,7 @@ function _createListOfBindings(flattenedBindings):List {
   return bindings;
 }
 
-function _flattenBindings(bindings:List, res:Map) {
+function _flattenBindings(bindings:List, res:Map):Map {
   ListWrapper.forEach(bindings, function (b) {
     if (b instanceof ResolvedBinding) {
       MapWrapper.set(res, b.key.id, b);

modules/angular2/src/di/opaque_token.js

@@ -10,7 +10,7 @@ export class OpaqueToken {
     this._desc = `Token(${desc})`;
   }
 
-  toString() {
+  toString():string {
     return this._desc;
   }
 }

modules/angular2/src/directives/class.js

@@ -15,7 +15,7 @@ export class CSSClass {
     this._domEl = ngEl.domElement;
   }
 
-  _toggleClass(className, enabled) {
+  _toggleClass(className, enabled):void {
     if (enabled) {
       DOM.addClass(this._domEl, className);
     } else {

modules/angular2/src/directives/if.js

@@ -40,7 +40,7 @@ export class If {
     this.prevCondition = null;
   }
 
-  set condition(newCondition) {
+  set condition(newCondition /* boolean */) {
     if (newCondition && (isBlank(this.prevCondition) || !this.prevCondition)) {
       this.prevCondition = true;
       this.viewContainer.create();

modules/angular2/src/directives/switch.js

@@ -65,7 +65,7 @@ export class Switch {
     this._switchValue = value;
   }
 
-  _onWhenValueChanged(oldWhen, newWhen, viewContainer: ViewContainer) {
+  _onWhenValueChanged(oldWhen, newWhen, viewContainer: ViewContainer):void {
     this._deregisterViewContainer(oldWhen, viewContainer);
     this._registerViewContainer(newWhen, viewContainer);
 
@@ -88,7 +88,7 @@ export class Switch {
     }
   }
 
-  _emptyAllActiveViewContainers() {
+  _emptyAllActiveViewContainers():void {
     var activeContainers = this._activeViewContainers;
     for (var i = 0; i < activeContainers.length; i++) {
       activeContainers[i].remove();
@@ -96,7 +96,7 @@ export class Switch {
     this._activeViewContainers = ListWrapper.create();
   }
 
-  _activateViewContainers(containers: List<ViewContainer>) {
+  _activateViewContainers(containers: List<ViewContainer>):void {
     // TODO(vicb): assert(this._activeViewContainers.length === 0);
     if (isPresent(containers)) {
       for (var i = 0; i < containers.length; i++) {
@@ -106,7 +106,7 @@ export class Switch {
     }
   }
 
-  _registerViewContainer(value, container: ViewContainer) {
+  _registerViewContainer(value, container: ViewContainer): void {
     var containers = MapWrapper.get(this._valueViewContainers, value);
     if (isBlank(containers)) {
       containers = ListWrapper.create();
@@ -115,7 +115,7 @@ export class Switch {
     ListWrapper.push(containers, container);
   }
 
-  _deregisterViewContainer(value, container: ViewContainer) {
+  _deregisterViewContainer(value, container: ViewContainer):void {
     // `_whenDefault` is used a marker for non-registered whens
     if (value == _whenDefault) return;
     var containers = MapWrapper.get(this._valueViewContainers, value);

modules/angular2/src/dom/dom_adapter.js

@@ -195,7 +195,7 @@ export class DomAdapter {
   attributeMap(element) {
     throw _abstract();
   }
-  getAttribute(element, attribute:string) {
+  getAttribute(element, attribute:string):string {
     throw _abstract();
   }
   setAttribute(element, name:string, value:string) {