ERROR Error: Uncaught (in promise): ReferenceError: Validators is not defined

Hi Guys ,

Today I have faced this error :

ERROR Error: Uncaught (in promise): ReferenceError: Validators is not defined

When I check the command prompt the error is like this :

-----ng serve--------------------------------------------------------------------------------------------------------------

ERROR in src/app/sign-up/sign-up.component.ts(17,27): error TS2304: Cannot find name 'Validators'.

src/app/sign-up/sign-up.component.ts(17,48): error TS2304: Cannot find name 'Validators'.

src/app/sign-up/sign-up.component.ts(17,73): error TS2304: Cannot find name 'Validators'.

-----------------------------------------------------------------------------------------------------------------------

The solution is to add the following line in your component.ts file, highlighted in Yellow.

import { Validators } from '@angular/forms';

The complete console log is as below:

ERROR Error: Uncaught (in promise): ReferenceError: Validators is not defined

ReferenceError: Validators is not defined

    at new SignUpComponent (sign-up.component.ts:17)

    at createClass (core.js:9292)

    at createDirectiveInstance (core.js:9179)

    at createViewNodes (core.js:10399)

    at createRootView (core.js:10313)

    at callWithDebugContext (core.js:11344)

    at Object.debugCreateRootView [as createRootView] (core.js:10831)

    at ComponentFactory_.push../node_modules/@angular/core/fesm5/core.js.ComponentFactory_.create (core.js:8659)

    at ComponentFactoryBoundToModule.push../node_modules/@angular/core/fesm5/core.js.ComponentFactoryBoundToModule.create (core.js:3311)

    at ViewContainerRef_.push../node_modules/@angular/core/fesm5/core.js.ViewContainerRef_.createComponent (core.js:8769)

    at resolvePromise (zone.js:831)

    at resolvePromise (zone.js:788)

    at zone.js:892

    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:423)

    at Object.onInvokeTask (core.js:3811)

    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:422)

    at Zone.push../node_modules/zone.js/dist/zone.js.Zone.runTask (zone.js:195)

    at drainMicroTaskQueue (zone.js:601)

defaultErrorLogger @ core.js:1673

localhost/:1 Unchecked runtime.lastError: The message port closed before a response was received.

core.js:1673 ERROR Error: Uncaught (in promise): ReferenceError: Validators is not defined

ReferenceError: Validators is not defined

    at new SignUpComponent (sign-up.component.ts:17)

    at createClass (core.js:9292)

    at createDirectiveInstance (core.js:9179)

    at createViewNodes (core.js:10399)

    at createRootView (core.js:10313)

    at callWithDebugContext (core.js:11344)

    at Object.debugCreateRootView [as createRootView] (core.js:10831)

    at ComponentFactory_.push../node_modules/@angular/core/fesm5/core.js.ComponentFactory_.create (core.js:8659)

    at ComponentFactoryBoundToModule.push../node_modules/@angular/core/fesm5/core.js.ComponentFactoryBoundToModule.create (core.js:3311)

    at ViewContainerRef_.push../node_modules/@angular/core/fesm5/core.js.ViewContainerRef_.createComponent (core.js:8769)

    at resolvePromise (zone.js:831)

    at resolvePromise (zone.js:788)

    at zone.js:892

    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:423)

    at Object.onInvokeTask (core.js:3811)

    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:422)

    at Zone.push../node_modules/zone.js/dist/zone.js.Zone.runTask (zone.js:195)

    at drainMicroTaskQueue (zone.js:601)

    at ZoneTask.push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask [as invoke] (zone.js:502)

    at invokeTask (zone.js:1744)

defaultErrorLogger @ core.js:1673

Uncaught Error: Template parse errors:'router-outlet' is not a known element:

Hi Guys ,

Today I have faced this error :

Uncaught Error: Template parse errors:'router-outlet' is not a known element:

The solution is to add the following line in app.module.ts highlighted in Yellow.

@NgModule({
imports: [
    BrowserModule,
    RouterModule.forRoot(appRoutes),
    FormsModule             
],

The complete console log is as below:

Uncaught Error: Template parse errors:

'router-outlet' is not a known element:

1. If 'router-outlet' is an Angular component, then verify that it is part of this module.

2. If 'router-outlet' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message. ("

   <a routerLink= "/explore"> Explore </a>

 </nav>

 [ERROR ->]<router-outlet></router-outlet>

<form #form="ngForm" (ngSubmit)="onSubmit(form.value)">

 <label>Name:"): ng:///AppModule/AppComponent.html@5:1

    at syntaxError (compiler.js:1021)

    at TemplateParser.push../node_modules/@angular/compiler/fesm5/compiler.js.TemplateParser.parse (compiler.js:14830)

    at JitCompiler.push../node_modules/@angular/compiler/fesm5/compiler.js.JitCompiler._parseTemplate (compiler.js:24018)

    at JitCompiler.push../node_modules/@angular/compiler/fesm5/compiler.js.JitCompiler._compileTemplate (compiler.js:24005)

    at compiler.js:23948

    at Set.forEach (<anonymous>)

    at JitCompiler.push../node_modules/@angular/compiler/fesm5/compiler.js.JitCompiler._compileComponents (compiler.js:23948)

    at compiler.js:23858

    at Object.then (compiler.js:1012)

    at JitCompiler.push../node_modules/@angular/compiler/fesm5/compiler.js.JitCompiler._compileModuleAndComponents (compiler.js:23857)

This project uses version 5.5.12 of RxJs, which is not supported by Angular v6.

Hi Guys,

You will face this error if you use angular 6.

This project uses version 5.5.12 of RxJs, which is not supported by Angular v6.

The solution is to change the version of rxjs in package.json

-----------package.json-----------------------------------

 "rxjs": "6.3.3"

---------------------------------------------------

Can't bind to 'ngModel' since it isn't a known property of 'input'

Hey Guys ,

Today let's look at the following error :

'Can't bind to 'ngModel' since it isn't a known property of 'input"

This will come in case of two way binding.

The fix is simple , you need to import the forms module to your app module.

-----------app.module----------------------------

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
FormsModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

-----------------------------------------------------------------------------

Import the two lines highlighted above and it should work fine .

View full source at here

Cannot assign to 'name' because it is a constant or a read-only property.

Hi Guys,

I have faced an error like "Cannot assign to 'name' because it is a constant or a read-only property." .

The code is as below

------------app.component.ts-----------------------------------
import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html' //// refer app.component.html for property binding
})
export class AppComponent {
  name="";

  testEventBind(userName: string) {
      name=userName;
  }
}

------------------------------------------------------------

I have highlighted the line which causes this error.

All you have to do is to use this keyword , change the highlighted line as below,

this.name=userName;

This should fix the issue.

ERROR in node_modules/rxjs/internal/types.d.ts(81,44): error TS1005: ';' expected.

Hey Guys ,

I have faced this issue on serving a newly created project using angular cli.
ERROR in node_modules/rxjs/internal/types.d.ts(81,44): error TS1005: ';' expected.
node_modules/rxjs/internal/types.d.ts(81,74): error TS1005: ';' expected.
node_modules/rxjs/internal/types.d.ts(81,77): error TS1109: Expression expected.

Solution 1:
Remove the ^ symbol from package.json from
  "rxjs": "^6.0.0",


execute :
npm update

it should work fine.If this doesn't work try this:

Solution 2:
In package.json set the version of rxjs as below:
 "rxjs": "6.3.3",


execute :
npm update

it should work.A working version is here click

Failed to start connector [Connector[HTTP/1.1-8080]]

Hey Guys,

Today I faced an issue while starting Spring boot application .

Full stacktrace is as below :

 o.apache.catalina.core.StandardService   : Failed to start connector [Connector[HTTP/1.1-8080]]

org.apache.catalina.LifecycleException: Failed to start component [Connector[HTTP/1.1-8080]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        at org.apache.catalina.core.StandardService.addConnector(StandardService.java:225) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.addPreviouslyRemovedConnectors(TomcatWebServer.java:256) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer.java:198) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.startWebServer(ServletWebServerApplicationContext.java:300) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:162) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553) [spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:333) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1277) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1265) [spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at hello.Application.main(Application.java:15) [classes!/:0.1.0]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Unknown Source) ~[na:na]
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) [gs-spring-boot-0.1.0.jar:0.1.0]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) [gs-spring-boot-0.1.0.jar:0.1.0]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) [gs-spring-boot-0.1.0.jar:0.1.0]
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) [gs-spring-boot-0.1.0.jar:0.1.0]
Caused by: org.apache.catalina.LifecycleException: Protocol handler start failed
        at org.apache.catalina.connector.Connector.startInternal(Connector.java:1020) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        ... 21 common frames omitted
Caused by: java.net.BindException: Address already in use: bind
        at java.base/sun.nio.ch.Net.bind0(Native Method) ~[na:na]
        at java.base/sun.nio.ch.Net.bind(Unknown Source) ~[na:na]
        at java.base/sun.nio.ch.Net.bind(Unknown Source) ~[na:na]
        at java.base/sun.nio.ch.ServerSocketChannelImpl.bind(Unknown Source) ~[na:na]
        at java.base/sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source) ~[na:na]
        at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:219) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:1151) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:591) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        at org.apache.catalina.connector.Connector.startInternal(Connector.java:1018) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
        ... 22 common frames omitted

2019-02-03 20:49:07.448  INFO 7964 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2019-02-03 20:49:07.502  INFO 7964 --- [           main] ConditionEvaluationReportLoggingListener :

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-02-03 20:49:07.508 ERROR 7964 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   :

***************************
APPLICATION FAILED TO START
***************************

Description:

The Tomcat connector configured to listen on port 8080 failed to start. The port may already be in use or the connector may be misconfigured.

Action:

Verify the connector's configuration, identify and stop any process that's listening on port 8080, or configure this application to listen on another port.

2019-02-03 20:49:07.510  INFO 7964 --- [           main] ConfigServletWebServerApplicationContext : Closing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@5af3afd9: startup date [Sun Feb 03 20:49:01 IST 2019]; root of context hierarchy
2019-02-03 20:49:07.512  INFO 7964 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Unregistering JMX-exposed beans on shutdown



The fix is simple , just add a property file like this :
application.properties--------------------------
server.port = 8989
--------------------------------------------------------

The error is due to default port 8080 is already in use.
The solution is to change the port number .