error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class

Question

First time using firestore and I'm getting this error. It seems to be a problem with Ivy, from my research. I don't have a lot of experience modifying tsconfig.app.json, which is the direction I've been pointed to, following other answers.

The only thing I was able to modify from the original project was to use Angular Fire 6 instead of 5, which I had done initially to follow a tutorial.

Here's package.json:

{
  "name": "language",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "~9.0.1",
    "@angular/cdk": "^9.0.0",
    "@angular/common": "~9.0.1",
    "@angular/compiler": "~9.0.1",
    "@angular/core": "~9.0.1",
    "@angular/fire": "^6.0.0-rc.1",
    "@angular/flex-layout": "^9.0.0-beta.29",
    "@angular/forms": "~9.0.1",
    "@angular/material": "^9.0.0",
    "@angular/platform-browser": "~9.0.1",
    "@angular/platform-browser-dynamic": "~9.0.1",
    "@angular/router": "~9.0.1",
    "firebase": "^7.8.2",
    "rxjs": "~6.5.4",
    "rxjs-compat": "^6.5.4",
    "tslib": "^1.10.0",
    "zone.js": "~0.10.2"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.900.2",
    "@angular/cli": "~9.0.2",
    "@angular/compiler-cli": "~9.0.1",
    "@angular/language-service": "~9.0.1",
    "@types/node": "^12.11.1",
    "@types/jasmine": "~3.3.8",
    "@types/jasminewd2": "~2.0.3",
    "codelyzer": "^5.1.2",
    "jasmine-core": "~3.4.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.1.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.15.0",
    "typescript": "~3.7.5",
    "@angular-devkit/architect": "^0.900.0-0 || ^0.900.0",
    "firebase-tools": "^7.12.1",
    "fuzzy": "^0.1.3",
    "inquirer": "^6.2.2",
    "inquirer-autocomplete-prompt": "^1.0.1"
  }
}

angular.json

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "language": {
      "projectType": "application",
      "schematics": {
        "@schematics/angular:component": {
          "style": "scss"
        }
      },
      "root": "",
      "sourceRoot": "src",
      "prefix": "app",
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/language",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "tsconfig.app.json",
            "aot": true,
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "./node_modules/@angular/material/prebuilt-themes/deeppurple-amber.css",
              "src/styles.scss"
            ],
            "scripts": []
          },
          "configurations": {
            "production": {
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.prod.ts"
                }
              ],
              "optimization": true,
              "outputHashing": "all",
              "sourceMap": false,
              "extractCss": true,
              "namedChunks": false,
              "extractLicenses": true,
              "vendorChunk": false,
              "buildOptimizer": true,
              "budgets": [
                {
                  "type": "initial",
                  "maximumWarning": "2mb",
                  "maximumError": "5mb"
                },
                {
                  "type": "anyComponentStyle",
                  "maximumWarning": "6kb",
                  "maximumError": "10kb"
                }
              ]
            }
          }
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "language:build"
          },
          "configurations": {
            "production": {
              "browserTarget": "language:build:production"
            }
          }
        },
        "extract-i18n": {
          "builder": "@angular-devkit/build-angular:extract-i18n",
          "options": {
            "browserTarget": "language:build"
          }
        },
        "test": {
          "builder": "@angular-devkit/build-angular:karma",
          "options": {
            "main": "src/test.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "tsconfig.spec.json",
            "karmaConfig": "karma.conf.js",
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "./node_modules/@angular/material/prebuilt-themes/deeppurple-amber.css",
              "src/styles.scss"
            ],
            "scripts": []
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": [
              "tsconfig.app.json",
              "tsconfig.spec.json",
              "e2e/tsconfig.json"
            ],
            "exclude": [
              "**/node_modules/**"
            ]
          }
        },
        "e2e": {
          "builder": "@angular-devkit/build-angular:protractor",
          "options": {
            "protractorConfig": "e2e/protractor.conf.js",
            "devServerTarget": "language:serve"
          },
          "configurations": {
            "production": {
              "devServerTarget": "language:serve:production"
            }
          }
        },
        "deploy": {
          "builder": "@angular/fire:deploy",
          "options": {}
        }
      }
    }
  },
  "defaultProject": "language"
}

tsconfig.app.json

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "outDir": "./out-tsc/app",
    "types": [],
  
  },
  "files": [
    "src/main.ts",
    "src/polyfills.ts"
  ],
  "include": [
    "src/**/*.d.ts"
  ],
  "exclude": [
    "src/test.ts",
    "src/**/*.spec.ts"
  ]
}

Thanks!

Strickler

restarting console helped me – Bohman

Dup component incorrectly nested in multiple modules. Asked for better error descrip: github.com/angular/angular/issues/40616 – Sura

This error also occurs when you miss @ before NgModule – Deferent

Pablo, point 1. in Venkata Thrivedi's answer below is the only thing required for this specific error message. unfortunately, the package.json, angular.json, and tsconfig.app.json files you posted actually don't matter in this case... – Carroty

Answer 1

Your module is not yet loaded by the Angular Server in node ng serve, so restart your server so the server loads the module that you just added in @NgModule app.module.ts

Look at jejakhacker.com

Bryna

I've been finding out that many times restarting the server or restarting IDE will do the trick :D – Strickler

Hi, I'm still getting the issues with the mono-repo workspace.Where it has root node_modules. – Novak

I'm still finding that I swear I've restarted since I made a change like this, but... turns out I didn't and restarting fixed it. Thanks for reminding me that I need to "turn it off and on again" before even googling! – Markowitz

Yeah. I was getting this error in core.module with Angular 11. When i run "ng serve" error gone. – Implore

You would need to restart VSCode in order for Angular Language Service to recompile the packages. – Judicature

Actually angular should provide a hint in the error log itself to restart and check! – Bitner

Restarting the terminal had done the trick in Angular10. – Ode

Ctrl+C => Y && npm start in VS Code terminal. Worked for Angular 12! – Necropolis

Thank you! Simple but worked for me. VS Code Reload: F1 > Type Reload Window > Press Return Thanks again. – Balaam

Or you did not safe a file after moving it the file into another directory/changing it. – Layfield

Answer 2

This error shows when you add component declaration in imports: [] instead of declarations: [], e.g:

declarations: [
  AppComponent,
],
imports: [
  BrowserModule,
  AppRoutingModule,
  SomeComponent <-----------wrong
],

Drunkometer

This! Also check other declaration properties too, such as providers, etc. Make sure they all have correct and valid values set. – Atelier

Answer 3

I got this error when I made the bonehead mistake of importing MatSnackBar instead of MatSnackBarModule in app.module.ts.

Ersatz

Fellow Bonehead here - MatCheckboxModule - Your answer was useful, thanks – Gauffer

Training material is great, but you really learn by doing :) – Pomander

The same thing happened for me with HttpClient. Updated HttpClient to HttpClientModule in my app.module.ts and the issue was resolved. – Keratose

I signed in for the the first time in years just to say Thanks ;) – Arianna

sigh...MatAutocompleteModule - I don't know how long it would have taken me to realize without your comment, thank you. – Doleful

But I am getting below error on doing this, Property 'open' does not exist on type 'MatSnackBarModule'. Any thoughts? – Volplane

I believe open is a method on MatSnackBar, not MatSnackBarModule, but you would probably get better responses by posting that as its own question. – Ersatz

Answer 4

I made a mistake by adding a service into imports array instead of providers array.

@NgModule({
  imports: [
    MyService // wrong here
  ],
  providers: [
    MyService // should add here
  ]
})
export class AppModule { }

Angular says you need to add Injectables into providers array.

Insecure

Totally agree with this. In my case with ng12, I switched from using ngx-clipboard to the now "built-into-angular" @angular/cdk/clipboard. I imported ClipboardModule correctly, but the "Clipboard" export is actually a service. Removing it from Exports and placing in Providers did the trick for me. – Courtund

Answer 5

Fixed it by opting out of Ivy as per documentation.

https://angular.io/guide/ivy

Change tsconfig.app.json to opt out of Ivy.

"enableIvy": false

Strickler

Folks, disabling Ivy which will soon to be the ONLY rendering engine for Angular is not the way to go. I understand if you're needing to push to prod ASAP because of reasons but you should diagnose and find out what is really causing your issue. – Ballenger

@AaronJordan I think the issue is moreso that Ivy is not production-ready, contrary to what the Angular team says. A production-ready upgrade should not have near the amount of bugs that Ivy has. Also, View Engine is not going away anytime soon for backwards-compatibility reasons (same reason why Angular library builds still happen in View Engine, not Ivy) – Montana

@u Ah...I don't see Ivy has a lot of bugs. Where is your reference? – Supplicant

In most instances @AaronJordan is right. However I've found that disabling Ivy is more stable when developing local libraries and hot loading into another project. Related answer: https://mcmap.net/q/111098/-angular-9-library-publish-error-quot-trying-to-publish-a-package-that-has-been-compiled-by-ivy-quot – Culminant

Answer 6

Sometimes when you change/update @NgModule in your project, projects get compiled but changes doesn't get reflect. So, restart once to get expected results if you not get it. ng serve

Pasteup

saved me a bunch of wasted time thank you. should have known this by now. – Rhetoric

Answer 7

This works for me:

1) Stop the ng server

2) Reinstall your package

npm install your-package-name

3) Run all again

ng serve

Syrian

Answer 8

try to clear cache

1. npm cache clean --force
2. npm install

Courtneycourtrai

It seems like correct command is npm cache clean --force – Electrotechnics

Answer 9

My mistake: I was missing the Module part, I wrote

import { MatPaginator } from '@angular/material/paginator';

instead of

import { MatPaginatorModule } from '@angular/material/paginator';

in my module.

Scarcity

Answer 10

For me I was working under Ubuntu

The error disappeared if I use sudo with ng

sudo ng build
sudo ng serve

A better solution is to grant the current user the needed permissions on the current folder using the following command:

sudo chown -R `whoami` ./

Doing so will let you run ng commands without sudo.

Gaylene

this answer helped me to resolve my issues – Glossology

It is likely you have installed something as root. It maybe time to check out the project again using the user account and building it there. Issue with using root is you may install a bad npm package by accident and end up with a hacked system. see answer by Shankar Ganesh for how to reset security. – Norvil

works as same here project created using root – Animalcule

Answer 11

This can also occur when using the wrong import (for example when using autoimport). let's take the MatTimePickerModule as an example. This will give an error message that is similar to the one described in the question:

import { NgxMatTimepickerModule } from '@angular-material-components/datetime-picker/lib/timepicker.module';

This should instead be

import { NgxMatTimepickerModule } from '@angular-material-components/datetime-picker';

Noncooperation

Just my one cent. The file had imports as import { MatFormField, MatHint, MatLabel } from '@angular/material/form-field';. It should be instead import { MatFormFieldModule } from '@angular/material/form-field'; When imports are wrong, then also the same error occurs. It took me 1hr. I almost was about to disable Ivy. I was using Angular version 11 – Competition

Answer 12

In my case I got this solved by setting "strictTemplates" back to false in tsconfig.json

{
  "compilerOptions": {
    // ...
  },
  "angularCompilerOptions": {
    "strictTemplates": false
  }
}

I had previously set this to true to prevent a VStudio pop-up from showing:

Burt

Worked for me thanks, despite being in pre-ivy version: angular8 – Tetraspore

For me this just hid the error and made it compile but the website didn't work, it didn't render the component. – Flabby

Answer 13

This works for me

1. Stop the ng server(ctrl+c)

2. Run Again

   npm start / ng serve --open
   

Consciousness

Answer 14

This issue will be fixed by adding the postinstall script below in your package.json.

It will be run after a npm install.

"scripts": {
   "postinstall": "ngcc"
}

Post adding the above code, run npm install

This works for me when upgrading to Angular 9+

Castellano

Answer 15

I have faced the same issue in Ubuntu because the Angular app directory was having root permission. Changing the ownership to the local user solved the issue for me.

$ sudo -i
$ chown -R <username>:<group> <ANGULAR_APP>
$ exit 
$ cd <ANGULAR_APP>
$ ng serve

Pallet

Wow you've saved my day! My Angular code was in Docker and all the files belonged to "root". Angular couldn't access a file, and gave me this cryptic error! – Sotelo

@Sotelo How would you change the ownership to the local user? I am using windows, and in the "properties>security>advanced" of the app folder did not find any such option. Please guide. – Volplane

Answer 16

I was importing mat-list. My mistake was using the following:

import { MatList } from "@angular/material/list";
@NgModule({
  exports: [
    MatList,
  ]
})

I forgot to append 'Module' suffix to the import and export declaration. The following fixed the problem:

import { MatListModule } from "@angular/material/list";
@NgModule({
  exports: [        
    MatListModule, // <-- Add 'Module' suffix here!
  ]
})

Perretta

Answer 17

What fixed it for me was matching the version of angular material & adapter to the lowest version of another angular module. Then reinstalled & re-ran.

    "@angular-devkit/schematics": "^10.1.2",
    "@angular/animations": "^10.1.2",
    "@angular/cdk": "^10.2.1",
    "@angular/common": "10.1.2",
    "@angular/compiler": "10.1.2",
    "@angular/core": "10.1.2",
    "@angular/forms": "10.1.2",
    "@angular/localize": "^10.1.2",
    "@angular/material": "^10.2.1",
    "@angular/material-moment-adapter": "^10.2.1",
    "@angular/platform-browser": "10.1.2",
    "@angular/platform-browser-dynamic": "10.1.2",
    "@angular/router": "10.1.2",

As you can see my cdk was 10.2.1, and my material was also 10.2.1. I saw the lowest version used was 10.1.2, so i changed the versions:

    "@angular/material": "^10.1.2", (was 10.2.1)
    "@angular/material-moment-adapter": "^10.1.2", (was 10.2.1)

to 10.1.2, ran "npm install" and then "ng serve", and it compiled successfully.

Donegal

Answer 18

I faced issue on Angular 12 and the issue is my colleague defined the component in page module and as well as the common module we use globally in project.

Removed from globally file module, issue resolved.

On My Case

Photometry

Answer 19

Work for me

angular.json

"aot": false

Legalese

Answer 20

i simply change my import from import from { AngularFirestore} from '@angular/fire/firestore'; to import { AngularFirestoreModule } from '@angular/fire/firestore';

and it's working fine

Sternwheeler

Answer 21

It also happens when you import some mat components which is not used anywhere in your components.

• if you have all mat components imported in you app.module.ts you have imported some mat components and you have not used any of the components in imports and exports arrays in app.module.ts means no issues no errors will throw works fine.

• if you create feature module for that let say by ng g m material this will create material.module.ts filename.

• now we have to copy all mat import statements to newly created feature module before copying keep in mind is any import statements grayed out or not(some indication IDE shows this name is not used). if grayed out means you have to remove those names then copy and paste it to MaterialModule imports and exports array. that's solve.

Doscher

Answer 22

1. App.Module.ts

   You can solve the error by adding the injectables in Provider not imports or declarations.

2. Inside Service.ts

   Add @injectable over the class

ex:

@Injectable()
 export class WebApiService {   }

even if you give space might not work

ex:

@Injectable()


export class WebApiService {    }

Welton

Answer 23

If you run npm install or yarn install with root account and run ng serve with a non-root account, you will encounter this issue.

Workaround: start server with root account as well

Conditioned

Answer 24

I was trying to add a custom pipe to my shared module and I've added it in import and export. That's why it caused this issue.

I solved this issue by adding my custom pipe into declarations:[], exports:[] and providers:[].

I solved this issue by following code :

@NgModule({

 declarations: [
   myCustomPipe,
 ],

 exports: [
   myCustomPipe,
 ],

 providers: [
  myCustomPipe,
 ]

})

Fallen

Answer 25

I don't know why but the only way I could solve it was to:

1. Import the module instead of the component
2. Match the folder name /my-component-y/ with MyComponentY.ts, I had /component-y/ and MyComponentY.ts

The root components are lazy loaded since it's for a mulitsite if that makes any difference.

Best solution is to use React/Next.js instead though of this old hacky framework.

Flabby

Answer 26

Nothing of all the anwers here helped on my side.

Short version: Remove the ".angular" (caching) folder in project root!

Long version: The NG6002 error came up in nearly every NgModule. It was consequential error because one of my directive (class CustomRouterLink extends RouterLink {}) had invalid injection tokens.

I fixed the injection token mistake, but angular still compained 100+ of the NG6002 errors. After hours of trying out all findings in the www, I just removed the ".angular" (caching) folder in project root, restartet the angular dev server.. TADAAA everything working again.

Bili

I don't know what good the .angular folder does - my angular doesn't build faster or anything and I've not noticed any improvement in behavior (other than symlinks seem to be more robust). I'd say the decision to create this angular cache causes a lot more problems than it fixed and, at least, should be made optional. – Cecilacecile

Answer 27

npm cache clean --force -> cleaning the cache maybe solve the issue.

Bevvy

its not related to cache, The issue is NgModule and providing in a wrong collection. – Borne

Answer 28

I have tested all the answers here but non of them worked for me. So I decided to change angular.js file. there is a aot option there which is true. then I altered that to the false and the error vanished!

"options": {
            "outputPath": "dist/DateMeUI",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "tsconfig.app.json",
            "aot": false, // here you have to change
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "src/styles.css"
            ],
            "scripts": []
          },

However, I got that there is 'tsconfig.app.json' which I couldn't find that in my project(maybe you have to add this manually ) by this file you can set the "enableIvy": false as others mention to it. tsconfig.app.json

Heddi

setting an aot to false, it is likely problem will occur in production. This is not a good solution. – Norvil

Answer 29

Just go to your tsconfig.app.json in your project and remove all from it

and copy below code and paste it. It will solve your issue :)

/* To learn more about this file see: https://angular.io/config/tsconfig. */
{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "outDir": "./out-tsc/app",
    "types": [],
  },

  "files": [
    "src/main.ts",
    "src/polyfills.ts"
  ],
  "include": [
    "src/**/*.d.ts"
  ],
  "angularCompilerOptions": {
    "enableIvy": false
  }
}

Cantata

Answer 30

In my case the problem was calling .forRoot() from some child modules that were meant to be re-used.

Hoag

Answer 31

I got this error while making a shared directive. Now Initially it got into declarations array of the app module (by default after I ran command with cli).

I had it into shared module declarations array and exports array. Now as soon as I removed it from app.module.ts file the issue got resolved.

The issue was it was declared inside 2 modules (shared and app.module). Removed from the app.module and voila!

Rouge

Answer 32

In my case, the problem was with the latest node. I was dockerizing the Angular app and using the latest node version like FROM node:latest as build

To make it work use Angular supported node versions like FROM node:14.17.4

Tessie

Answer 33

it can be occurs when you import a module that you already installed, but one ore more of its dependencies are missing

Alexio

Answer 34

restart visual studio code so Angular Language Service to recompile the packages

Desmid

Answer 35

Removing the node_modules, clearing the npm cache and reinstalling the node_modules again fixed this issue for me.

rm -rf node_modules/
npm cache clean -f
npm i

Imminence