Bootstrap modal not working in stackblitz with Angular 8

I am trying to open a twitter bootstrap modal on click of a button in Angular 8 environment in Stackblitz. But it is not working. I will not use ng-bootstrap or any other modal library except twitter bootstrap 4. Could you help me find the issue? Thanks in advance. The code: https://stackblitz.com/edit/angular-qajssu?file=app/app.component.html