Hướng dẫn upgrade tại đây:
npm install -g npm-check-updates
ncu
ncu -u
npm install
sudo npm install -g rxjs-tslint rxjs-5-to-6-migrate -p src/tsconfig.app.json
npm install @angular/cdk --save
npm i -S core-js@2.5.7
Change all "es6" and "es7" to "es" in your polyfills.ts and polyfills.ts (Optional). From: import 'core-js/es6/symbol'; To: import 'core-js/es/symbol';
First thing is you need to change your import in app.component.ts from
import { BsModalRef } from 'ngx-bootstrap/modal/bs-modal-ref.service';
to
import { BsModalRef } from 'ngx-bootstrap';