Component is part of the declaration of 2 modules

Question

I try to build an ionic 2 app. When I try the app in the browser with ionic serve or launch it on an emulator everything works fine.

But when I try to build it every time the error

ionic-app-script tast: "build"
Error Type AddEvent in "PATH"/add.event.ts is part of the declarations of 2 modules: AppModule in "PATH"/app.modules.ts and AddEvent in "PATH"/add-event.module.ts.
Please consider moving AddEvent in "PATH"/add-event.ts to a higher module that imports AppModule in "PATH"/app.module.ts and AddEventModule.
You can also creat a new NgModule that exports and includes AddEvent then import that NgModule in AppModule and AddEventModule

my AppModule is

import { NgModule, ErrorHandler } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { IonicApp, IonicModule, IonicErrorHandler } from 'ionic-angular';
import { AngularFireModule } from 'angularfire2';
import { MyApp } from './app.component';
import { Eventdata } from '../providers/eventdata';
import { AuthProvider } from '../providers/auth-provider';
import { HttpModule } from '@angular/http';

import { HomePage } from '../pages/home/home';
import { Login } from '../pages/login/login';
import { Register } from '../pages/register/register';
import { AddEvent } from '../pages/add-event/add-event';
import { EventDetails } from '../pages/event-details/event-details';

import { StatusBar } from '@ionic-native/status-bar';
import { SplashScreen } from '@ionic-native/splash-screen';


@NgModule({
  declarations: [
    MyApp,
    HomePage,
    Login,
    Register,
    AddEvent,
    EventDetails

  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp),
    HttpModule,
    AngularFireModule.initializeApp(config)
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage,
    Login,
    Register,
    AddEvent,
    EventDetails
  ],
  providers: [
    StatusBar,
    SplashScreen,
    {provide: ErrorHandler, useClass: IonicErrorHandler}, Eventdata, AuthProvider
  ]
})
export class AppModule {}

and my add-event.module.ts is

import { NgModule } from '@angular/core';
import { IonicPageModule } from 'ionic-angular';
import { AddEvent } from './add-event';

@NgModule({
  declarations: [
    AddEvent,
  ],
  imports: [
    IonicPageModule.forChild(AddEvent),
  ],
  exports: [
    AddEvent
  ]
})
export class AddEventModule {}

I understand that I have to remove one of the declarations, but I dont know how.

If I remove the declaration from AppModule I get an Error that the Login Page is not found, while running ionic serve

Answer 1

Some people using Lazy loading are going to stumble across this page.

Here is what I did to fix sharing a directive.

1. create a new shared module

shared.module.ts

import { NgModule, Directive,OnInit, EventEmitter, Output, OnDestroy, Input,ElementRef,Renderer } from '@angular/core';
import { CommonModule } from '@angular/common';

import { SortDirective } from './sort-directive';

@NgModule({
  imports: [
  ],
  declarations: [
  SortDirective
  ],
  exports: [
    SortDirective
  ]
})

export class SharedModule { }

Then in app.module and your other module(s)

import {SharedModule} from '../directives/shared.module'
...

@NgModule({
   imports: [
       SharedModule
       ....
       ....
 ]
})
export class WhateverModule { }

Answer 2

Since the Ionic 3.6.0 release every page generated using Ionic-CLI is now an Angular module. This means you've to add the module to your imports in the file src/app/app.module.ts

import { BrowserModule } from "@angular/platform-browser";
import { ErrorHandler, NgModule } from "@angular/core";
import { IonicApp, IonicErrorHandler, IonicModule } from "ionic-angular";
import { SplashScreen } from "@ionic-native/splash-screen";
import { StatusBar } from "@ionic-native/status-bar";;

import { MyApp } from "./app.component";
import { HomePage } from "../pages/home/home"; // import the page
import {HomePageModule} from "../pages/home/home.module"; // import the module

@NgModule({
  declarations: [
    MyApp,
  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp),
    HomePageModule // declare the module
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage, // declare the page
  ],
  providers: [
    StatusBar,
    SplashScreen,
    { provide: ErrorHandler, useClass: IonicErrorHandler },
  ]
})
export class AppModule {}

Answer 3

Solved it -- Component is part of the declaration of 2 modules

1. Remove pagename.module.ts file in app
2. Remove import { IonicApp } from 'ionic-angular'; in pagename.ts file
3. Remove @IonicPage() from pagename.ts file

And Run the command ionic cordova build android --prod --release its Working in my app

Answer 4

I had the same error but I discovered that when you import an AddEventModule, you can't import an AddEvent module as it would present an error in this case.

Answer 5

Remove the declaration from AppModule, but update the AppModule configuration to import your AddEventModule.

.....
import { AddEventModule } from './add-event.module';  // <-- don't forget to import the AddEventModule class

@NgModule({
  declarations: [
    MyApp,
    HomePage,
    Login,
    Register,
    //AddEvent,  <--- remove this
    EventDetails

  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp),
    HttpModule,
    AngularFireModule.initializeApp(config),
    AddEventModule,  // <--- add this import here
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage,
    Login,
    Register,
    AddEvent,
    EventDetails
  ],
  providers: [
    StatusBar,
    SplashScreen,
    {provide: ErrorHandler, useClass: IonicErrorHandler}, Eventdata, AuthProvider
  ]
})
export class AppModule {}

Also,

Note that it's important that your AddEventModule exports the AddEvent component if you want to use it outside that module. Luckily, you already have that configured, but if it was omitted, you would've gotten an error if you tried to use the AddEvent component in another component of your AppModule

Answer 6

If your pages is created by using CLI then it creates a file with filename.module.ts then you have to register your filename.module.ts in imports array in app.module.ts file and don't insert that page in declarations array.

eg.

import { LoginPageModule } from '../login/login.module';


declarations: [
    MyApp,
    LoginPageModule,// remove this and add it below array i.e. imports
],

imports: [
        BrowserModule,
        HttpModule,
        IonicModule.forRoot(MyApp, {
           scrollPadding: false,
           scrollAssist: true,
           autoFocusAssist: false,
           tabsHideOnSubPages:false
        }),
       LoginPageModule,
],