import {Component, OnInit, AfterViewInit} from '@angular/core';
declare var $: any;
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent  implements AfterViewInit{
  title = 'app works!';

  ngAfterViewInit() {
    $('.datepicker').pickadate();
  }

}

<div class="md-form">
  <input placeholder="Selected date" type="text" id="date-picker-example" class="form-control datepicker">
  <label for="date-picker-example">Try me...</label>
</div>

  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/mdbootstrap/4.3.0/css/mdb.min.css" />
  <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mdbootstrap/4.3.0/js/mdb.min.js"></script>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>