title: Ng-bootstrap and Angular 9 compatibility
body: <p>After upgrading to Angular 9, I am getting the following errors relative to ng-bootstrap:</p>
  <p>ERROR in src/app/shared/Components/form-controls/dropdown-select/dropdown-select.component.ts:87:63 -
  error TS2304: Cannot find name 'NgbDropdownMenu'.</p>
  <p>87   @ViewChild('dropdownMenu', { static: false }) dropDownMenu: NgbDropdownMenu;
  ~~~~~~~~~~~~~~~
  src/app/private/private-shared/Services/ngb-modal-stack-extend.service.ts:1:39 - error TS2305: Module     '&quot;../../../../../../../../../../../node_modules/@ng-bootstrap/ng-bootstrap&quot;' has no exported member 'isString'. 1 import { NgbModalRef, NgbActiveModal, isString, isDefined, NgbModalBackdrop, ContentRef, NgbModal,
  NgbModalWindow } from '@ng-bootstrap/ng-bootstrap';
  ~~~~~~~~
  src/app/private/private-shared/Services/ngb-modal-stack-extend.service.ts:1:49 - error TS2305: Module
  '&quot;../../../../../../../../../../../node_modules/@ng-bootstrap/ng-bootstrap/ng-bootstrap&quot;' has no
  exported member 'isDefined'.
  1 import { NgbModalRef, NgbActiveModal, isString, isDefined, NgbModalBackdrop, ContentRef, NgbModal,
  NgbModalWindow } from '@ng-bootstrap/ng-bootstrap';
  ~~~~~~~~~
  src/app/private/private-shared/Services/ngb-modal-stack-extend.service.ts:1:60 - error TS2305: Module '&quot;../../../../../../../../../../../node_modules/@ng-bootstrap/ng-bootstrap/ng-bootstrap&quot;' has no
  exported member 'NgbModalBackdrop'.</p>
  <p>1 import { NgbModalRef, NgbActiveModal, isString, isDefined, NgbModalBackdrop, ContentRef, NgbModal,
  NgbModalWindow } from '@ng-bootstrap/ng-bootstrap';
  ~~~~~~~~~~~~~~~~
  src/app/private/private-shared/Services/ngb-modal-stack-extend.service.ts:1:78 - error TS2305: Module
  '&quot;../../../../../../../../../../../node_modules/@ng-bootstrap/ng-bootstrap/ng-bootstrap&quot;' has no
  exported member 'ContentRef'.
  1 import { NgbModalRef, NgbActiveModal, isString, isDefined, NgbModalBackdrop, ContentRef, NgbModal,
  NgbModalWindow } from '@ng-bootstrap/ng-bootstrap';
  ~~~~~~~~~~
  src/app/private/private-shared/Services/ngb-modal-stack-extend.service.ts:1:100 - error TS2305:
  Module '&quot;../../../../../../../../../../../node_modules/@ng-bootstrap/ng-bootstrap/ng-bootstrap&quot;' has
  no exported member 'NgbModalWindow'.</p>
  <p>1 import { NgbModalRef, NgbActiveModal, isString, isDefined, NgbModalBackdrop, ContentRef, NgbModal,
  NgbModalWindow } from '@ng-bootstrap/ng-bootstrap';</p>
  <pre>
  
  Package.json 
  
      &quot;@angular/cdk&quot;: &quot;9.2.4&quot;,
      &quot;@angular/common&quot;: &quot;9.1.11&quot;,
      &quot;@angular/compiler&quot;: &quot;9.1.11&quot;,
      &quot;@angular/core&quot;: &quot;9.1.11&quot;,
      &quot;@angular/forms&quot;: &quot;9.1.11&quot;,
      &quot;@angular/localize&quot;: &quot;9.1.11&quot;,
      &quot;@angular/material&quot;: &quot;9.2.4&quot;,
      &quot;@angular/platform-browser&quot;: &quot;9.1.11&quot;,
      &quot;@angular/platform-browser-dynamic&quot;: &quot;9.1.11&quot;,
      &quot;@angular/router&quot;: &quot;9.1.11&quot;,
      &quot;@ng-bootstrap/ng-bootstrap&quot;: &quot;4.1.2&quot;,
      &quot;rxjs&quot;: &quot;6.3.3&quot;,
      },
      &quot;devDependencies&quot;: {
         &quot;@angular-builders/jest&quot;: &quot;^7.2.0&quot;,
        &quot;@angular-devkit/build-angular&quot;: &quot;~0.1000.0&quot;,
        &quot;@angular/cli&quot;: &quot;^9.1.9&quot;,
        &quot;@angular/compiler-cli&quot;: &quot;9.1.11&quot;,
        &quot;@schematics/angular&quot;: &quot;^9.1.5&quot;,
  </pre>