refactor(facade): Inline isBlank called with object-type argument (#11992)

modules/@angular/benchpress/src/web_driver_extension.ts

@@ -9,7 +9,6 @@
 import {Injector, OpaqueToken} from '@angular/core';
 
 import {Options} from './common_options';
-import {isBlank} from './facade/lang';
 
 export type PerfLogEvent = {
   [key: string]: any
@@ -50,7 +49,7 @@ export abstract class WebDriverExtension {
               delegate = extension;
             }
           });
-          if (isBlank(delegate)) {
+          if (!delegate) {
             throw new Error('Could not find a delegate for given capabilities!');
           }
           return delegate;

modules/@angular/benchpress/src/webdriver/ios_driver_extension.ts

@@ -52,7 +52,7 @@ export class IOsDriverExtension extends WebDriverExtension {
 
   /** @internal */
   private _convertPerfRecordsToEvents(records: any[], events: PerfLogEvent[] = null) {
-    if (isBlank(events)) {
+    if (!events) {
       events = [];
     }
     records.forEach((record) => {

modules/@angular/benchpress/test/metric/perflog_metric_spec.ts

@@ -11,7 +11,7 @@ import {AsyncTestCompleter, beforeEach, describe, expect, inject, it} from '@ang
 
 import {Metric, Options, PerfLogEvent, PerfLogFeatures, PerflogMetric, ReflectiveInjector, WebDriverExtension} from '../../index';
 import {StringMapWrapper} from '../../src/facade/collection';
-import {isBlank, isPresent} from '../../src/facade/lang';
+import {isPresent} from '../../src/facade/lang';
 import {TraceEventFactory} from '../trace_event_factory';
 
 export function main() {
@@ -28,11 +28,11 @@ export function main() {
         requestCount?: boolean
       } = {}): Metric {
     commandLog = [];
-    if (isBlank(perfLogFeatures)) {
+    if (!perfLogFeatures) {
       perfLogFeatures =
           new PerfLogFeatures({render: true, gc: true, frameCapture: true, userTiming: true});
     }
-    if (isBlank(microMetrics)) {
+    if (!microMetrics) {
       microMetrics = {};
     }
     var providers: Provider[] = [

modules/@angular/benchpress/test/metric/user_metric_spec.ts

@@ -10,7 +10,6 @@ import {Provider, ReflectiveInjector} from '@angular/core';
 import {AsyncTestCompleter, describe, expect, inject, it} from '@angular/core/testing/testing_internal';
 
 import {Options, PerfLogEvent, PerfLogFeatures, UserMetric, WebDriverAdapter} from '../../index';
-import {isBlank} from '../../src/facade/lang';
 
 export function main() {
   var wdAdapter: MockDriverAdapter;
@@ -18,11 +17,11 @@ export function main() {
   function createMetric(
       perfLogs: PerfLogEvent[], perfLogFeatures: PerfLogFeatures,
       {userMetrics}: {userMetrics?: {[key: string]: string}} = {}): UserMetric {
-    if (isBlank(perfLogFeatures)) {
+    if (!perfLogFeatures) {
       perfLogFeatures =
           new PerfLogFeatures({render: true, gc: true, frameCapture: true, userTiming: true});
     }
-    if (isBlank(userMetrics)) {
+    if (!userMetrics) {
       userMetrics = {};
     }
     wdAdapter = new MockDriverAdapter();

modules/@angular/benchpress/test/reporter/console_reporter_spec.ts

@@ -25,7 +25,7 @@ export function main() {
           metrics?: {[key: string]: any}
         }) {
       log = [];
-      if (isBlank(descriptions)) {
+      if (!descriptions) {
         descriptions = [];
       }
       if (isBlank(sampleId)) {

modules/@angular/benchpress/test/runner_spec.ts

@@ -9,7 +9,6 @@
 import {AsyncTestCompleter, describe, expect, inject, it} from '@angular/core/testing/testing_internal';
 
 import {Injector, Metric, Options, ReflectiveInjector, Runner, SampleDescription, SampleState, Sampler, Validator, WebDriverAdapter} from '../index';
-import {isBlank} from '../src/facade/lang';
 
 export function main() {
   describe('runner', () => {
@@ -17,7 +16,7 @@ export function main() {
     var runner: Runner;
 
     function createRunner(defaultProviders: any[] = null): Runner {
-      if (isBlank(defaultProviders)) {
+      if (!defaultProviders) {
         defaultProviders = [];
       }
       runner = new Runner([

modules/@angular/benchpress/test/sampler_spec.ts

@@ -26,10 +26,10 @@ export function main() {
       execute?: any
     } = {}) {
       var time = 1000;
-      if (isBlank(metric)) {
+      if (!metric) {
         metric = new MockMetric([]);
       }
-      if (isBlank(reporter)) {
+      if (!reporter) {
         reporter = new MockReporter([]);
       }
       if (isBlank(driver)) {

modules/@angular/benchpress/test/webdriver/chrome_driver_extension_spec.ts

@@ -35,7 +35,7 @@ export function main() {
     function createExtension(
         perfRecords: any[] = null, userAgent: string = null,
         messageMethod = 'Tracing.dataCollected'): WebDriverExtension {
-      if (isBlank(perfRecords)) {
+      if (!perfRecords) {
         perfRecords = [];
       }
       if (isBlank(userAgent)) {

modules/@angular/benchpress/test/webdriver/ios_driver_extension_spec.ts

@@ -9,7 +9,7 @@
 import {AsyncTestCompleter, describe, expect, inject, it} from '@angular/core/testing/testing_internal';
 
 import {IOsDriverExtension, ReflectiveInjector, WebDriverAdapter, WebDriverExtension} from '../../index';
-import {Json, isBlank} from '../../src/facade/lang';
+import {Json} from '../../src/facade/lang';
 import {TraceEventFactory} from '../trace_event_factory';
 
 export function main() {
@@ -20,7 +20,7 @@ export function main() {
     var normEvents = new TraceEventFactory('timeline', 'pid0');
 
     function createExtension(perfRecords: any[] = null): WebDriverExtension {
-      if (isBlank(perfRecords)) {
+      if (!perfRecords) {
         perfRecords = [];
       }
       log = [];
@@ -156,7 +156,7 @@ function timeEndRecord(name: string, time: number) {
 }
 
 function durationRecord(type: string, startTime: number, endTime: number, children: any[] = null) {
-  if (isBlank(children)) {
+  if (!children) {
     children = [];
   }
   return {'type': type, 'startTime': startTime, 'endTime': endTime, 'children': children};

modules/@angular/common/test/pipes/async_pipe_spec.ts

@@ -13,7 +13,6 @@ import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {browserDetection} from '@angular/platform-browser/testing/browser_util';
 
 import {EventEmitter} from '../../src/facade/async';
-import {isBlank} from '../../src/facade/lang';
 import {SpyChangeDetectorRef} from '../spies';
 
 export function main() {
@@ -112,7 +111,7 @@ export function main() {
       var promise: Promise<any>;
       var ref: SpyChangeDetectorRef;
       // adds longer timers for passing tests in IE
-      var timer = (!isBlank(getDOM()) && browserDetection.isIE) ? 50 : 10;
+      var timer = (getDOM() && browserDetection.isIE) ? 50 : 10;
 
       beforeEach(() => {
         promise = new Promise((res, rej) => {

modules/@angular/compiler-cli/test/static_reflector_spec.ts

@@ -454,7 +454,7 @@ class MockReflectorHost implements StaticReflectorHost {
   getStaticSymbol(declarationFile: string, name: string, members?: string[]): StaticSymbol {
     var cacheKey = `${declarationFile}:${name}${members?'.'+members.join('.'):''}`;
     var result = this.staticTypeCache.get(cacheKey);
-    if (isBlank(result)) {
+    if (!result) {
       result = new StaticSymbol(declarationFile, name, members);
       this.staticTypeCache.set(cacheKey, result);
     }

modules/@angular/compiler/src/animation/animation_compiler.ts

@@ -7,7 +7,7 @@
  */
 
 import {StringMapWrapper} from '../facade/collection';
-import {isBlank, isPresent} from '../facade/lang';
+import {isPresent} from '../facade/lang';
 import {Identifiers, resolveIdentifier} from '../identifiers';
 import * as o from '../output/output_ast';
 import {ANY_STATE, DEFAULT_STATE, EMPTY_STATE} from '../private_import_core';
@@ -323,7 +323,7 @@ class _AnimationBuilderStateMap {
   get states() { return this._states; }
   registerState(name: string, value: {[prop: string]: string | number} = null): void {
     var existingEntry = this._states[name];
-    if (isBlank(existingEntry)) {
+    if (!existingEntry) {
       this._states[name] = value;
     }
   }

modules/@angular/compiler/src/ml_parser/parser.ts

@@ -123,7 +123,7 @@ class _TreeBuilder {
     // read =
     while (this._peek.type === lex.TokenType.EXPANSION_CASE_VALUE) {
       let expCase = this._parseExpansionCase();
-      if (isBlank(expCase)) return;  // error
+      if (!expCase) return;  // error
       cases.push(expCase);
     }
 
@@ -154,7 +154,7 @@ class _TreeBuilder {
     const start = this._advance();
 
     const exp = this._collectExpansionExpTokens(start);
-    if (isBlank(exp)) return null;
+    if (!exp) return null;
 
     const end = this._advance();
     exp.push(new lex.Token(lex.TokenType.EOF, [], end.sourceSpan));

modules/@angular/compiler/src/ng_module_compiler.ts

@@ -9,7 +9,7 @@
 import {Injectable} from '@angular/core';
 
 import {CompileDiDependencyMetadata, CompileIdentifierMetadata, CompileNgModuleMetadata, CompileProviderMetadata, CompileTokenMetadata} from './compile_metadata';
-import {isBlank, isPresent} from './facade/lang';
+import {isPresent} from './facade/lang';
 import {Identifiers, resolveIdentifier, resolveIdentifierToken} from './identifiers';
 import * as o from './output/output_ast';
 import {convertValueToOutputAst} from './output/value_util';
@@ -190,7 +190,7 @@ class _InjectorBuilder {
       resolvedProviderValueExpr = providerValueExpressions[0];
       type = providerValueExpressions[0].type;
     }
-    if (isBlank(type)) {
+    if (!type) {
       type = o.DYNAMIC_TYPE;
     }
     if (isEager) {
@@ -223,11 +223,11 @@ class _InjectorBuilder {
                resolveIdentifierToken(Identifiers.ComponentFactoryResolver).reference)) {
         result = o.THIS_EXPR;
       }
-      if (isBlank(result)) {
+      if (!result) {
         result = this._instances.get(dep.token.reference);
       }
     }
-    if (isBlank(result)) {
+    if (!result) {
       var args = [createDiTokenExpression(dep.token)];
       if (dep.isOptional) {
         args.push(o.NULL_EXPR);

modules/@angular/compiler/src/output/output_ast.ts

@@ -8,7 +8,7 @@
 
 
 import {CompileIdentifierMetadata} from '../compile_metadata';
-import {isBlank, isPresent, isString} from '../facade/lang';
+import {isPresent, isString} from '../facade/lang';
 
 
 
@@ -19,7 +19,7 @@ export enum TypeModifier {
 
 export abstract class Type {
   constructor(public modifiers: TypeModifier[] = null) {
-    if (isBlank(modifiers)) {
+    if (!modifiers) {
       this.modifiers = [];
     }
   }
@@ -462,7 +462,7 @@ export enum StmtModifier {
 
 export abstract class Statement {
   constructor(public modifiers: StmtModifier[] = null) {
-    if (isBlank(modifiers)) {
+    if (!modifiers) {
       this.modifiers = [];
     }
   }
@@ -517,7 +517,7 @@ export class ReturnStatement extends Statement {
 
 export class AbstractClassPart {
   constructor(public type: Type = null, public modifiers: StmtModifier[]) {
-    if (isBlank(modifiers)) {
+    if (!modifiers) {
       this.modifiers = [];
     }
   }

modules/@angular/compiler/src/provider_analyzer.ts

@@ -136,8 +136,7 @@ export class ProviderElementContext {
       requestingProviderType: ProviderAstType, token: CompileTokenMetadata,
       eager: boolean): ProviderAst {
     var resolvedProvider = this._allProviders.get(token.reference);
-    if (isBlank(resolvedProvider) ||
-        ((requestingProviderType === ProviderAstType.Directive ||
+    if (!resolvedProvider || ((requestingProviderType === ProviderAstType.Directive ||
                                requestingProviderType === ProviderAstType.PublicService) &&
                               resolvedProvider.providerType === ProviderAstType.PrivateService) ||
         ((requestingProviderType === ProviderAstType.PrivateService ||
@@ -239,12 +238,12 @@ export class ProviderElementContext {
       result = this._getLocalDependency(requestingProviderType, dep, eager);
     }
     if (dep.isSelf) {
-      if (isBlank(result) && dep.isOptional) {
+      if (!result && dep.isOptional) {
         result = new CompileDiDependencyMetadata({isValue: true, value: null});
       }
     } else {
       // check parent elements
-      while (isBlank(result) && isPresent(currElement._parent)) {
+      while (!result && isPresent(currElement._parent)) {
         var prevElement = currElement;
         currElement = currElement._parent;
         if (prevElement._isViewRoot) {
@@ -253,7 +252,7 @@ export class ProviderElementContext {
         result = currElement._getLocalDependency(ProviderAstType.PublicService, dep, currEager);
       }
       // check @Host restriction
-      if (isBlank(result)) {
+      if (!result) {
         if (!dep.isHost || this.viewContext.component.type.isHost ||
             this.viewContext.component.type.reference === dep.token.reference ||
             isPresent(this.viewContext.viewProviders.get(dep.token.reference))) {
@@ -265,7 +264,7 @@ export class ProviderElementContext {
         }
       }
     }
-    if (isBlank(result)) {
+    if (!result) {
       this.viewContext.errors.push(
           new ProviderError(`No provider for ${dep.token.name}`, this._sourceSpan));
     }
@@ -311,7 +310,7 @@ export class NgModuleProviderAnalyzer {
 
   private _getOrCreateLocalProvider(token: CompileTokenMetadata, eager: boolean): ProviderAst {
     var resolvedProvider = this._allProviders.get(token.reference);
-    if (isBlank(resolvedProvider)) {
+    if (!resolvedProvider) {
       return null;
     }
     var transformedProviderAst = this._transformedProviders.get(token.reference);
@@ -414,7 +413,7 @@ function _normalizeProviders(
     providers: Array<CompileProviderMetadata|CompileTypeMetadata|any[]>,
     sourceSpan: ParseSourceSpan, targetErrors: ParseError[],
     targetProviders: CompileProviderMetadata[] = null): CompileProviderMetadata[] {
-  if (isBlank(targetProviders)) {
+  if (!targetProviders) {
     targetProviders = [];
   }
   if (isPresent(providers)) {
@@ -479,7 +478,7 @@ function _resolveProviders(
           `Mixing multi and non multi provider is not possible for token ${resolvedProvider.token.name}`,
           sourceSpan));
     }
-    if (isBlank(resolvedProvider)) {
+    if (!resolvedProvider) {
       const lifecycleHooks =
           provider.token.identifier && provider.token.identifier instanceof CompileTypeMetadata ?
           provider.token.identifier.lifecycleHooks :
@@ -530,7 +529,7 @@ function _getContentQueries(directives: CompileDirectiveMetadata[]):
 function _addQueryToTokenMap(map: Map<any, CompileQueryMetadata[]>, query: CompileQueryMetadata) {
   query.selectors.forEach((token: CompileTokenMetadata) => {
     var entry = map.get(token.reference);
-    if (isBlank(entry)) {
+    if (!entry) {
       entry = [];
       map.set(token.reference, entry);
     }

modules/@angular/compiler/src/runtime_compiler.ts

@@ -12,7 +12,7 @@ import {AnimationParser} from './animation/animation_parser';
 import {CompileDirectiveMetadata, CompileIdentifierMetadata, CompileNgModuleMetadata, CompilePipeMetadata, ProviderMeta, createHostComponentMeta} from './compile_metadata';
 import {CompilerConfig} from './config';
 import {DirectiveNormalizer} from './directive_normalizer';
-import {isBlank, stringify} from './facade/lang';
+import {stringify} from './facade/lang';
 import {CompileMetadataResolver} from './metadata_resolver';
 import {NgModuleCompiler} from './ng_module_compiler';
 import * as ir from './output/output_ast';
@@ -191,7 +191,7 @@ export class RuntimeCompiler implements Compiler {
 
   private _createCompiledHostTemplate(compType: Type<any>): CompiledTemplate {
     var compiledTemplate = this._compiledHostTemplateCache.get(compType);
-    if (isBlank(compiledTemplate)) {
+    if (!compiledTemplate) {
       var compMeta = this._metadataResolver.getDirectiveMetadata(compType);
       assertComponent(compMeta);
       var hostMeta = createHostComponentMeta(compMeta);
@@ -206,7 +206,7 @@ export class RuntimeCompiler implements Compiler {
   private _createCompiledTemplate(
       compMeta: CompileDirectiveMetadata, ngModule: CompileNgModuleMetadata): CompiledTemplate {
     var compiledTemplate = this._compiledTemplateCache.get(compMeta.type.reference);
-    if (isBlank(compiledTemplate)) {
+    if (!compiledTemplate) {
       assertComponent(compMeta);
       compiledTemplate = new CompiledTemplate(
           false, compMeta.selector, compMeta.type, ngModule.transitiveModule.directives,

modules/@angular/compiler/src/selector.ts

@@ -216,7 +216,7 @@ export class SelectorMatcher {
         if (isTerminal) {
           var terminalMap = matcher._attrValueMap;
           var terminalValuesMap = terminalMap.get(attrName);
-          if (isBlank(terminalValuesMap)) {
+          if (!terminalValuesMap) {
             terminalValuesMap = new Map<string, SelectorContext[]>();
             terminalMap.set(attrName, terminalValuesMap);
           }
@@ -224,7 +224,7 @@ export class SelectorMatcher {
         } else {
           var parttialMap = matcher._attrValuePartialMap;
           var partialValuesMap = parttialMap.get(attrName);
-          if (isBlank(partialValuesMap)) {
+          if (!partialValuesMap) {
             partialValuesMap = new Map<string, SelectorMatcher>();
             parttialMap.set(attrName, partialValuesMap);
           }
@@ -237,7 +237,7 @@ export class SelectorMatcher {
   private _addTerminal(
       map: Map<string, SelectorContext[]>, name: string, selectable: SelectorContext) {
     var terminalList = map.get(name);
-    if (isBlank(terminalList)) {
+    if (!terminalList) {
       terminalList = [];
       map.set(name, terminalList);
     }
@@ -246,7 +246,7 @@ export class SelectorMatcher {
 
   private _addPartial(map: Map<string, SelectorMatcher>, name: string): SelectorMatcher {
     var matcher = map.get(name);
-    if (isBlank(matcher)) {
+    if (!matcher) {
       matcher = new SelectorMatcher();
       map.set(name, matcher);
     }
@@ -316,7 +316,7 @@ export class SelectorMatcher {
   _matchTerminal(
       map: Map<string, SelectorContext[]>, name: string, cssSelector: CssSelector,
       matchedCallback: (c: CssSelector, a: any) => void): boolean {
-    if (isBlank(map) || isBlank(name)) {
+    if (!map || isBlank(name)) {
       return false;
     }
 
@@ -325,7 +325,7 @@ export class SelectorMatcher {
     if (isPresent(starSelectables)) {
       selectables = selectables.concat(starSelectables);
     }
-    if (isBlank(selectables)) {
+    if (!selectables) {
       return false;
     }
     var selectable: SelectorContext;
@@ -341,11 +341,11 @@ export class SelectorMatcher {
   _matchPartial(
       map: Map<string, SelectorMatcher>, name: string, cssSelector: CssSelector,
       matchedCallback: (c: CssSelector, a: any) => void): boolean {
-    if (isBlank(map) || isBlank(name)) {
+    if (!map || isBlank(name)) {
       return false;
     }
     var nestedSelector = map.get(name);
-    if (isBlank(nestedSelector)) {
+    if (!nestedSelector) {
       return false;
     }
     // TODO(perf): get rid of recursion and measure again
@@ -374,13 +374,11 @@ export class SelectorContext {
 
   finalize(cssSelector: CssSelector, callback: (c: CssSelector, a: any) => void): boolean {
     var result = true;
-    if (this.notSelectors.length > 0 &&
-        (isBlank(this.listContext) || !this.listContext.alreadyMatched)) {
+    if (this.notSelectors.length > 0 && (!this.listContext || !this.listContext.alreadyMatched)) {
       var notMatcher = SelectorMatcher.createNotMatcher(this.notSelectors);
       result = !notMatcher.match(cssSelector, null);
     }
-    if (result && isPresent(callback) &&
-        (isBlank(this.listContext) || !this.listContext.alreadyMatched)) {
+    if (result && isPresent(callback) && (!this.listContext || !this.listContext.alreadyMatched)) {
       if (isPresent(this.listContext)) {
         this.listContext.alreadyMatched = true;
       }

modules/@angular/compiler/src/template_parser/template_parser.ts

@@ -12,7 +12,7 @@ import {CompileDirectiveMetadata, CompilePipeMetadata, CompileTemplateMetadata,
 import {AST, ASTWithSource, BindingPipe, EmptyExpr, Interpolation, ParserError, RecursiveAstVisitor, TemplateBinding} from '../expression_parser/ast';
 import {Parser} from '../expression_parser/parser';
 import {StringMapWrapper} from '../facade/collection';
-import {isBlank, isPresent, isString} from '../facade/lang';
+import {isPresent, isString} from '../facade/lang';
 import {I18NHtmlParser} from '../i18n/i18n_html_parser';
 import {Identifiers, identifierToken, resolveIdentifierToken} from '../identifiers';
 import * as html from '../ml_parser/ast';
@@ -869,7 +869,7 @@ class TemplateParseVisitor implements html.Visitor {
       const boundPropsByName = new Map<string, BoundElementOrDirectiveProperty>();
       boundProps.forEach(boundProp => {
         const prevValue = boundPropsByName.get(boundProp.name);
-        if (isBlank(prevValue) || prevValue.isLiteral) {
+        if (!prevValue || prevValue.isLiteral) {
           // give [a]="b" a higher precedence than a="b" on the same element
           boundPropsByName.set(boundProp.name, boundProp);
         }
@@ -900,7 +900,7 @@ class TemplateParseVisitor implements html.Visitor {
     });
 
     props.forEach((prop: BoundElementOrDirectiveProperty) => {
-      if (!prop.isLiteral && isBlank(boundDirectivePropsIndex.get(prop.name))) {
+      if (!prop.isLiteral && !boundDirectivePropsIndex.get(prop.name)) {
         boundElementProps.push(this._createElementPropertyAst(
             elementName, prop.name, prop.expression, prop.sourceSpan));
       }

modules/@angular/compiler/src/view_compiler/compile_element.ts

@@ -9,7 +9,7 @@
 
 import {CompileDiDependencyMetadata, CompileDirectiveMetadata, CompileIdentifierMetadata, CompileProviderMetadata, CompileQueryMetadata, CompileTokenMetadata} from '../compile_metadata';
 import {ListWrapper, MapWrapper, StringMapWrapper} from '../facade/collection';
-import {isBlank, isPresent} from '../facade/lang';
+import {isPresent} from '../facade/lang';
 import {Identifiers, identifierToken, resolveIdentifier, resolveIdentifierToken} from '../identifiers';
 import * as o from '../output/output_ast';
 import {convertValueToOutputAst} from '../output/value_util';
@@ -27,7 +27,7 @@ export class CompileNode {
       public parent: CompileElement, public view: CompileView, public nodeIndex: number,
       public renderNode: o.Expression, public sourceAst: TemplateAst) {}
 
-  isNull(): boolean { return isBlank(this.renderNode); }
+  isNull(): boolean { return !this.renderNode; }
 
   isRootElement(): boolean { return this.view != this.parent.view; }
 }
@@ -313,12 +313,12 @@ export class CompileElement extends CompileNode {
       requestingProviderType: ProviderAstType, dep: CompileDiDependencyMetadata): o.Expression {
     var result: o.Expression = null;
     // constructor content query
-    if (isBlank(result) && isPresent(dep.query)) {
+    if (!result && isPresent(dep.query)) {
       result = this._addQuery(dep.query, null).queryList;
     }
 
     // constructor view query
-    if (isBlank(result) && isPresent(dep.viewQuery)) {
+    if (!result && isPresent(dep.viewQuery)) {
       result = createQueryList(
           dep.viewQuery, null,
           `_viewQuery_${dep.viewQuery.selectors[0].name}_${this.nodeIndex}_${this._componentConstructorViewQueryLists.length}`,
@@ -328,7 +328,7 @@ export class CompileElement extends CompileNode {
 
     if (isPresent(dep.token)) {
       // access builtins with special visibility
-      if (isBlank(result)) {
+      if (!result) {
         if (dep.token.reference ===
             resolveIdentifierToken(Identifiers.ChangeDetectorRef).reference) {
           if (requestingProviderType === ProviderAstType.Component) {
@@ -339,7 +339,7 @@ export class CompileElement extends CompileNode {
         }
       }
       // access regular providers on the element
-      if (isBlank(result)) {
+      if (!result) {
         let resolvedProvider = this._resolvedProviders.get(dep.token.reference);
         // don't allow directives / public services to access private services.
         // only components and private services can access private services.
@@ -361,20 +361,20 @@ export class CompileElement extends CompileNode {
     if (dep.isValue) {
       result = o.literal(dep.value);
     }
-    if (isBlank(result) && !dep.isSkipSelf) {
+    if (!result && !dep.isSkipSelf) {
       result = this._getLocalDependency(requestingProviderType, dep);
     }
     // check parent elements
-    while (isBlank(result) && !currElement.parent.isNull()) {
+    while (!result && !currElement.parent.isNull()) {
       currElement = currElement.parent;
       result = currElement._getLocalDependency(
           ProviderAstType.PublicService, new CompileDiDependencyMetadata({token: dep.token}));
     }
 
-    if (isBlank(result)) {
+    if (!result) {
       result = injectFromViewParentInjector(dep.token, dep.isOptional);
     }
-    if (isBlank(result)) {
+    if (!result) {
       result = o.NULL_EXPR;
     }
     return getPropertyInView(result, this.view, currElement.view);
@@ -411,7 +411,7 @@ function createProviderProperty(
     resolvedProviderValueExpr = providerValueExpressions[0];
     type = providerValueExpressions[0].type;
   }
-  if (isBlank(type)) {
+  if (!type) {
     type = o.DYNAMIC_TYPE;
   }
   if (isEager) {

modules/@angular/compiler/src/view_compiler/compile_pipe.ts

@@ -8,7 +8,6 @@
 
 
 import {CompilePipeMetadata} from '../compile_metadata';
-import {isBlank} from '../facade/lang';
 import {Identifiers, resolveIdentifier, resolveIdentifierToken} from '../identifiers';
 import * as o from '../output/output_ast';
 
@@ -23,7 +22,7 @@ export class CompilePipe {
     if (meta.pure) {
       // pure pipes live on the component view
       pipe = compView.purePipes.get(name);
-      if (isBlank(pipe)) {
+      if (!pipe) {
         pipe = new CompilePipe(compView, meta);
         compView.purePipes.set(name, pipe);
         compView.pipes.push(pipe);
@@ -85,7 +84,7 @@ function _findPipeMeta(view: CompileView, name: string): CompilePipeMetadata {
       break;
     }
   }
-  if (isBlank(pipeMeta)) {
+  if (!pipeMeta) {
     throw new Error(
         `Illegal state: Could not find pipe ${name} although the parser should have detected this error!`);
   }

modules/@angular/compiler/src/view_compiler/compile_query.ts

@@ -8,7 +8,7 @@
 
 import {CompileQueryMetadata} from '../compile_metadata';
 import {ListWrapper} from '../facade/collection';
-import {isBlank, isPresent} from '../facade/lang';
+import {isPresent} from '../facade/lang';
 import {Identifiers, resolveIdentifier} from '../identifiers';
 import * as o from '../output/output_ast';
 
@@ -129,7 +129,7 @@ export function createQueryList(
 export function addQueryToTokenMap(map: Map<any, CompileQuery[]>, query: CompileQuery) {
   query.meta.selectors.forEach((selector) => {
     var entry = map.get(selector.reference);
-    if (isBlank(entry)) {
+    if (!entry) {
       entry = [];
       map.set(selector.reference, entry);
     }

modules/@angular/compiler/src/view_compiler/compile_view.ts

@@ -10,7 +10,7 @@ import {AnimationEntryCompileResult} from '../animation/animation_compiler';
 import {CompileDirectiveMetadata, CompileIdentifierMetadata, CompilePipeMetadata} from '../compile_metadata';
 import {CompilerConfig} from '../config';
 import {ListWrapper, MapWrapper} from '../facade/collection';
-import {isBlank, isPresent} from '../facade/lang';
+import {isPresent} from '../facade/lang';
 import {Identifiers, resolveIdentifier} from '../identifiers';
 import * as o from '../output/output_ast';
 import {ViewType} from '../private_import_core';
@@ -138,7 +138,7 @@ export class CompileView implements NameResolver {
     }
     var currView: CompileView = this;
     var result = currView.locals.get(name);
-    while (isBlank(result) && isPresent(currView.declarationElement.view)) {
+    while (!result && isPresent(currView.declarationElement.view)) {
       currView = currView.declarationElement.view;
       result = currView.locals.get(name);
     }

modules/@angular/compiler/src/view_compiler/event_binder.ts

@@ -8,7 +8,7 @@
 
 import {CompileDirectiveMetadata} from '../compile_metadata';
 import {StringMapWrapper} from '../facade/collection';
-import {StringWrapper, isBlank, isPresent} from '../facade/lang';
+import {StringWrapper, isPresent} from '../facade/lang';
 import {identifierToken} from '../identifiers';
 import * as o from '../output/output_ast';
 import {BoundEventAst, DirectiveAst} from '../template_parser/template_ast';
@@ -32,7 +32,7 @@ export class CompileEventListener {
     var listener = targetEventListeners.find(
         listener => listener.eventTarget == eventTarget && listener.eventName == eventName &&
             listener.eventPhase == eventPhase);
-    if (isBlank(listener)) {
+    if (!listener) {
       listener = new CompileEventListener(
           compileElement, eventTarget, eventName, eventPhase, targetEventListeners.length);
       targetEventListeners.push(listener);

modules/@angular/compiler/src/view_compiler/property_binder.ts

@@ -9,7 +9,7 @@
 import {SecurityContext} from '@angular/core';
 
 import * as cdAst from '../expression_parser/ast';
-import {isBlank, isPresent} from '../facade/lang';
+import {isPresent} from '../facade/lang';
 import {Identifiers, resolveIdentifier} from '../identifiers';
 import * as o from '../output/output_ast';
 import {EMPTY_STATE as EMPTY_ANIMATION_STATE, LifecycleHooks, isDefaultChangeDetectionStrategy} from '../private_import_core';
@@ -37,7 +37,7 @@ function bind(
     method: CompileMethod, bindingIndex: number) {
   var checkExpression = convertCdExpressionToIr(
       view, context, parsedExpression, DetectChangesVars.valUnwrapper, bindingIndex);
-  if (isBlank(checkExpression.expression)) {
+  if (!checkExpression.expression) {
     // e.g. an empty expression was given
     return;
   }

modules/@angular/compiler/src/view_compiler/util.ts

@@ -8,7 +8,7 @@
 
 
 import {CompileDirectiveMetadata, CompileTokenMetadata} from '../compile_metadata';
-import {isBlank, isPresent} from '../facade/lang';
+import {isPresent} from '../facade/lang';
 import {Identifiers, resolveIdentifier} from '../identifiers';
 import * as o from '../output/output_ast';
 import {createDiTokenExpression} from '../util';
@@ -84,7 +84,7 @@ export function createPureProxy(
   view.fields.push(new o.ClassField(pureProxyProp.name, null));
   var pureProxyId =
       argCount < Identifiers.pureProxies.length ? Identifiers.pureProxies[argCount] : null;
-  if (isBlank(pureProxyId)) {
+  if (!pureProxyId) {
     throw new Error(`Unsupported number of argument for pure functions: ${argCount}`);
   }
   view.createMethod.addStmt(o.THIS_EXPR.prop(pureProxyProp.name)

modules/@angular/compiler/test/output/js_emitter_spec.ts

@@ -11,8 +11,6 @@ import {JavaScriptEmitter} from '@angular/compiler/src/output/js_emitter';
 import * as o from '@angular/compiler/src/output/output_ast';
 import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 
-import {isBlank} from '../../src/facade/lang';
-
 import {SimpleJsImportGenerator} from './output_emitter_util';
 
 var someModuleUrl = 'asset:somePackage/lib/somePath';
@@ -39,7 +37,7 @@ export function main() {
     });
 
     function emitStmt(stmt: o.Statement, exportedVars: string[] = null): string {
-      if (isBlank(exportedVars)) {
+      if (!exportedVars) {
         exportedVars = [];
       }
       return emitter.emitStatements(someModuleUrl, [stmt], exportedVars);

modules/@angular/compiler/test/output/ts_emitter_spec.ts

@@ -11,8 +11,6 @@ import * as o from '@angular/compiler/src/output/output_ast';
 import {TypeScriptEmitter} from '@angular/compiler/src/output/ts_emitter';
 import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 
-import {isBlank} from '../../src/facade/lang';
-
 import {SimpleJsImportGenerator} from './output_emitter_util';
 
 var someModuleUrl = 'asset:somePackage/lib/somePath';
@@ -39,7 +37,7 @@ export function main() {
     });
 
     function emitStmt(stmt: o.Statement, exportedVars: string[] = null): string {
-      if (isBlank(exportedVars)) {
+      if (!exportedVars) {
         exportedVars = [];
       }
       return emitter.emitStatements(someModuleUrl, [stmt], exportedVars);

modules/@angular/core/src/change_detection/differs/default_iterable_differ.ts

@@ -722,7 +722,7 @@ class _DuplicateMap {
     var key = getMapKey(trackById);
 
     var recordList = this.map.get(key);
-    return isBlank(recordList) ? null : recordList.get(trackById, afterIndex);
+    return recordList ? recordList.get(trackById, afterIndex) : null;
   }
 
   /**

modules/@angular/core/src/change_detection/differs/iterable_differs.ts

@@ -8,7 +8,7 @@
 
 import {Optional, Provider, SkipSelf} from '../../di';
 import {ListWrapper} from '../../facade/collection';
-import {getTypeNameForDebugging, isBlank, isPresent} from '../../facade/lang';
+import {getTypeNameForDebugging, isPresent} from '../../facade/lang';
 import {ChangeDetectorRef} from '../change_detector_ref';
 
 
@@ -82,7 +82,7 @@ export class IterableDiffers {
     return {
       provide: IterableDiffers,
       useFactory: (parent: IterableDiffers) => {
-        if (isBlank(parent)) {
+        if (!parent) {
           // Typically would occur when calling IterableDiffers.extend inside of dependencies passed
           // to
           // bootstrap(), which would override default pipes instead of extending them.

modules/@angular/core/src/change_detection/differs/keyvalue_differs.ts

@@ -8,7 +8,7 @@
 
 import {Optional, Provider, SkipSelf} from '../../di';
 import {ListWrapper} from '../../facade/collection';
-import {isBlank, isPresent} from '../../facade/lang';
+import {isPresent} from '../../facade/lang';
 import {ChangeDetectorRef} from '../change_detector_ref';
 
 
@@ -72,7 +72,7 @@ export class KeyValueDiffers {
     return {
       provide: KeyValueDiffers,
       useFactory: (parent: KeyValueDiffers) => {
-        if (isBlank(parent)) {
+        if (!parent) {
           // Typically would occur when calling KeyValueDiffers.extend inside of dependencies passed
           // to
           // bootstrap(), which would override default pipes instead of extending them.

modules/@angular/core/src/di/reflective_errors.ts

@@ -8,7 +8,7 @@
 
 import {ListWrapper} from '../facade/collection';
 import {BaseError, WrappedError} from '../facade/errors';
-import {isBlank, stringify} from '../facade/lang';
+import {stringify} from '../facade/lang';
 import {Type} from '../type';
 
 import {ReflectiveInjector} from './reflective_injector';
@@ -229,7 +229,7 @@ export class NoAnnotationError extends BaseError {
     var signature: string[] = [];
     for (var i = 0, ii = params.length; i < ii; i++) {
       var parameter = params[i];
-      if (isBlank(parameter) || parameter.length == 0) {
+      if (!parameter || parameter.length == 0) {
         signature.push('?');
       } else {
         signature.push(parameter.map(stringify).join(' '));

modules/@angular/core/src/di/reflective_key.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {isBlank, stringify} from '../facade/lang';
+import {stringify} from '../facade/lang';
 
 import {resolveForwardRef} from './forward_ref';
 
@@ -32,7 +32,7 @@ export class ReflectiveKey {
    * Private
    */
   constructor(public token: Object, public id: number) {
-    if (isBlank(token)) {
+    if (!token) {
       throw new Error('Token must be defined!');
     }
   }

modules/@angular/core/src/di/reflective_provider.ts

@@ -201,7 +201,7 @@ function _normalizeProviders(providers: Provider[], res: Provider[]): Provider[]
 
 export function constructDependencies(
     typeOrFunc: any, dependencies: any[]): ReflectiveDependency[] {
-  if (isBlank(dependencies)) {
+  if (!dependencies) {
     return _dependenciesFor(typeOrFunc);
   } else {
     var params: any[][] = dependencies.map(t => [t]);
@@ -211,7 +211,7 @@ export function constructDependencies(
 
 function _dependenciesFor(typeOrFunc: any): ReflectiveDependency[] {
   var params = reflector.parameters(typeOrFunc);
-  if (isBlank(params)) return [];
+  if (!params) return [];
   if (params.some(isBlank)) {
     throw new NoAnnotationError(typeOrFunc, params);
   }

modules/@angular/core/src/linker/component_factory.ts

@@ -9,7 +9,6 @@
 import {ChangeDetectorRef} from '../change_detection/change_detection';
 import {Injector} from '../di/injector';
 import {unimplemented} from '../facade/errors';
-import {isBlank} from '../facade/lang';
 import {Type} from '../type';
 import {AppElement} from './element';
 import {ElementRef} from './element_ref';
@@ -101,7 +100,7 @@ export class ComponentFactory<C> {
       injector: Injector, projectableNodes: any[][] = null,
       rootSelectorOrNode: string|any = null): ComponentRef<C> {
     var vu: ViewUtils = injector.get(ViewUtils);
-    if (isBlank(projectableNodes)) {
+    if (!projectableNodes) {
       projectableNodes = [];
     }
     // Note: Host views don't need a declarationAppElement!

modules/@angular/core/src/linker/view_utils.ts

@@ -10,7 +10,7 @@ import {APP_ID} from '../application_tokens';
 import {devModeEqual} from '../change_detection/change_detection';
 import {UNINITIALIZED} from '../change_detection/change_detection_util';
 import {Inject, Injectable} from '../di';
-import {isBlank, isPresent, looseIdentical} from '../facade/lang';
+import {isPresent, looseIdentical} from '../facade/lang';
 import {ViewEncapsulation} from '../metadata/view';
 import {RenderComponentType, Renderer, RootRenderer} from '../render/api';
 import {Sanitizer} from '../security';
@@ -72,7 +72,7 @@ const EMPTY_ARR: any[] = [];
 
 export function ensureSlotCount(projectableNodes: any[][], expectedSlotCount: number): any[][] {
   var res: any[][];
-  if (isBlank(projectableNodes)) {
+  if (!projectableNodes) {
     res = EMPTY_ARR;
   } else if (projectableNodes.length < expectedSlotCount) {
     var givenSlotCount = projectableNodes.length;

modules/@angular/core/test/change_detection/util.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {isBlank} from '../../src/facade/lang';
+
 
 export function iterableChangesAsString(
     {collection = [] as any, previous = [] as any, additions = [] as any, moves = [] as any,
@@ -23,11 +23,11 @@ export function kvChangesAsString(
     {map, previous, additions, changes, removals}:
         {map?: any[], previous?: any[], additions?: any[], changes?: any[], removals?: any[]}):
     string {
-  if (isBlank(map)) map = [];
-  if (isBlank(previous)) previous = [];
-  if (isBlank(additions)) additions = [];
-  if (isBlank(changes)) changes = [];
-  if (isBlank(removals)) removals = [];
+  if (!map) map = [];
+  if (!previous) previous = [];
+  if (!additions) additions = [];
+  if (!changes) changes = [];
+  if (!removals) removals = [];
 
   return 'map: ' + map.join(', ') + '\n' +
       'previous: ' + previous.join(', ') + '\n' +

modules/@angular/core/test/di/reflective_injector_spec.ts

@@ -11,7 +11,7 @@ import {ReflectiveInjectorDynamicStrategy, ReflectiveInjectorInlineStrategy, Ref
 import {ResolvedReflectiveProvider_} from '@angular/core/src/di/reflective_provider';
 import {expect} from '@angular/platform-browser/testing/matchers';
 
-import {isBlank, isPresent, stringify} from '../../src/facade/lang';
+import {isPresent, stringify} from '../../src/facade/lang';
 
 class Engine {}
 
@@ -458,7 +458,7 @@ export function main() {
       it('should resolve and flatten', () => {
         var providers = ReflectiveInjector.resolve([Engine, [BrokenEngine]]);
         providers.forEach(function(b) {
-          if (isBlank(b)) return;  // the result is a sparse array
+          if (!b) return;  // the result is a sparse array
           expect(b instanceof ResolvedReflectiveProvider_).toBe(true);
         });
       });

modules/@angular/forms/src/directives/reactive_directives/form_group_directive.ts

@@ -10,7 +10,6 @@ import {Directive, Inject, Input, OnChanges, Optional, Output, Self, SimpleChang
 
 import {EventEmitter} from '../../facade/async';
 import {ListWrapper} from '../../facade/collection';
-import {isBlank} from '../../facade/lang';
 import {FormArray, FormControl, FormGroup} from '../../model';
 import {NG_ASYNC_VALIDATORS, NG_VALIDATORS, Validators} from '../../validators';
 import {ControlContainer} from '../control_container';
@@ -174,7 +173,7 @@ export class FormGroupDirective extends ControlContainer implements Form,
   }
 
   private _checkFormPresent() {
-    if (isBlank(this.form)) {
+    if (!this.form) {
       ReactiveErrors.missingFormException();
     }
   }

modules/@angular/forms/src/directives/shared.ts

@@ -35,8 +35,8 @@ export function controlPath(name: string, parent: ControlContainer): string[] {
 }
 
 export function setUpControl(control: FormControl, dir: NgControl): void {
-  if (isBlank(control)) _throwError(dir, 'Cannot find control with');
-  if (isBlank(dir.valueAccessor)) _throwError(dir, 'No value accessor for form control with');
+  if (!control) _throwError(dir, 'Cannot find control with');
+  if (!dir.valueAccessor) _throwError(dir, 'No value accessor for form control with');
 
   control.validator = Validators.compose([control.validator, dir.validator]);
   control.asyncValidator = Validators.composeAsync([control.asyncValidator, dir.asyncValidator]);
@@ -139,7 +139,7 @@ export function isBuiltInAccessor(valueAccessor: ControlValueAccessor): boolean
 // TODO: vsavkin remove it once https://github.com/angular/angular/issues/3011 is implemented
 export function selectValueAccessor(
     dir: NgControl, valueAccessors: ControlValueAccessor[]): ControlValueAccessor {
-  if (isBlank(valueAccessors)) return null;
+  if (!valueAccessors) return null;
 
   var defaultAccessor: ControlValueAccessor;
   var builtinAccessor: ControlValueAccessor;

modules/@angular/forms/src/validators.ts

@@ -114,7 +114,7 @@ export class Validators {
    * of the individual error maps.
    */
   static compose(validators: ValidatorFn[]): ValidatorFn {
-    if (isBlank(validators)) return null;
+    if (!validators) return null;
     var presentValidators = validators.filter(isPresent);
     if (presentValidators.length == 0) return null;
 
@@ -124,7 +124,7 @@ export class Validators {
   }
 
   static composeAsync(validators: AsyncValidatorFn[]): AsyncValidatorFn {
-    if (isBlank(validators)) return null;
+    if (!validators) return null;
     var presentValidators = validators.filter(isPresent);
     if (presentValidators.length == 0) return null;
 

modules/@angular/http/src/headers.ts

@@ -7,7 +7,6 @@
  */
 
 import {ListWrapper, MapWrapper, StringMapWrapper, isListLikeIterable, iterateListLike} from '../src/facade/collection';
-import {isBlank} from '../src/facade/lang';
 
 /**
  * Polyfill for [Headers](https://developer.mozilla.org/en-US/docs/Web/API/Headers/Headers), as
@@ -48,7 +47,7 @@ export class Headers {
 
     this._headersMap = new Map<string, string[]>();
 
-    if (isBlank(headers)) {
+    if (!headers) {
       return;
     }
 

modules/@angular/platform-browser/src/dom/dom_adapter.ts

@@ -8,8 +8,6 @@
 
 import {Type} from '@angular/core';
 
-import {isBlank} from '../facade/lang';
-
 var _DOM: DomAdapter = null;
 
 export function getDOM() {
@@ -21,7 +19,7 @@ export function setDOM(adapter: DomAdapter) {
 }
 
 export function setRootDomAdapter(adapter: DomAdapter) {
-  if (isBlank(_DOM)) {
+  if (!_DOM) {
     _DOM = adapter;
   }
 }

modules/@angular/platform-browser/src/dom/dom_renderer.ts

@@ -34,7 +34,7 @@ export abstract class DomRootRenderer implements RootRenderer {
 
   renderComponent(componentProto: RenderComponentType): Renderer {
     var renderer = this.registeredComponents.get(componentProto.id);
-    if (isBlank(renderer)) {
+    if (!renderer) {
       renderer = new DomRenderer(this, componentProto, this.animationDriver);
       this.registeredComponents.set(componentProto.id, renderer);
     }

modules/@angular/platform-browser/src/dom/events/key_events.ts

@@ -8,7 +8,7 @@
 
 import {Injectable, NgZone} from '@angular/core';
 
-import {ListWrapper, StringMapWrapper} from '../../facade/collection';
+import {ListWrapper} from '../../facade/collection';
 import {StringWrapper, isPresent} from '../../facade/lang';
 import {getDOM} from '../dom_adapter';
 

modules/@angular/platform-browser/test/browser_util_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {StringMapWrapper} from '../src/facade/collection';
+
 import {BrowserDetection} from '../testing/browser_util';
 
 export function main() {

modules/@angular/platform-server/src/parse5_adapter.ts

@@ -135,7 +135,7 @@ export class Parse5DomAdapter extends DomAdapter {
   }
   on(el: any /** TODO #9100 */, evt: any /** TODO #9100 */, listener: any /** TODO #9100 */) {
     var listenersMap: {[k: string]: any} = el._eventListenersMap;
-    if (isBlank(listenersMap)) {
+    if (!listenersMap) {
       var listenersMap: {[k: string]: any} = {};
       el._eventListenersMap = listenersMap;
     }

modules/@angular/platform-webworker/src/web_workers/shared/client_message_broker.ts

@@ -9,7 +9,6 @@
 import {Injectable, Type} from '@angular/core';
 
 import {EventEmitter} from '../../facade/async';
-import {StringMapWrapper} from '../../facade/collection';
 import {DateWrapper, StringWrapper, isPresent, print, stringify} from '../../facade/lang';
 
 import {MessageBus} from './message_bus';

modules/@angular/platform-webworker/src/web_workers/worker/renderer.ts

@@ -9,7 +9,7 @@
 import {Injectable, RenderComponentType, Renderer, RootRenderer, ViewEncapsulation} from '@angular/core';
 
 import {ListWrapper} from '../../facade/collection';
-import {isBlank, isPresent} from '../../facade/lang';
+import {isPresent} from '../../facade/lang';
 import {AnimationKeyframe, AnimationPlayer, AnimationStyles, RenderDebugInfo} from '../../private_import_core';
 import {ClientMessageBrokerFactory, FnArg, UiArguments} from '../shared/client_message_broker';
 import {MessageBus} from '../shared/message_bus';
@@ -50,7 +50,7 @@ export class WebWorkerRootRenderer implements RootRenderer {
 
   renderComponent(componentType: RenderComponentType): Renderer {
     var result = this._componentRenderers.get(componentType.id);
-    if (isBlank(result)) {
+    if (!result) {
       result = new WebWorkerRenderer(this, componentType);
       this._componentRenderers.set(componentType.id, result);
       var id = this._renderStore.allocateId();
@@ -243,11 +243,11 @@ export class NamedEventEmitter {
   private _listeners: Map<string, Function[]>;
 
   private _getListeners(eventName: string): Function[] {
-    if (isBlank(this._listeners)) {
+    if (!this._listeners) {
       this._listeners = new Map<string, Function[]>();
     }
     var listeners = this._listeners.get(eventName);
-    if (isBlank(listeners)) {
+    if (!listeners) {
       listeners = [];
       this._listeners.set(eventName, listeners);
     }