error NG8002: Can't bind to 'state' since it isn't a known property of 'a'. code example

Example 1: Can't bind to 'ngModel' since it isn't a known property of 'input'.

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

[...]

@NgModule({
  imports: [
    [...]
    FormsModule
  ],
  [...]
})

Example 2: Can't bind to 'formGroup' since it isn't a known property of 'form'

// To fix this error, you just need to import ReactiveFormsModule from @angular/forms in your module. 

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

@NgModule({
    imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule
    ],
    declarations: [
        AppComponent
    ],
    bootstrap: [AppComponent]
})

export class AppModule { }

Example 3: Uncaught Error: Template parse errors: Can't bind to 'ngModel'

Try to import FormModule an app.module.ts file

import { FormsModule } from '@angular/forms'

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