Angular 4 Ngx-datatable Filter not working object is null but accessed (even with if condition)

Question

I'm using ngx-datatable and I tried to add filter ability to my code but it dosen't work at all.

This is my code :

import {Component, OnInit, ViewChild, ViewEncapsulation} from '@angular/core';
import {NavbarService} from '../../Services/navbar.service';
import {DataService} from '../../Services/data.service';
import {DatatableComponent} from '@swimlane/ngx-datatable';
import {forEach} from '@angular/router/src/utils/collection';

@Component({
  selector: 'app-student',
  templateUrl: './student.component.html',
  styleUrls: ['./student.component.css'],
  encapsulation: ViewEncapsulation.None
})
export class StudentComponent implements OnInit {
  rows: Student[];
  @ViewChild('myTable') table: any;

  students: Student[];
  temp = [];

  constructor(private nav: NavbarService, public dataService: DataService) {
    this.dataService.getStudents().subscribe(Students => {
      this.Students = [...Students];
      this.rows = Students;
    });
  }

  ngOnInit() {
    this.nav.show();
  }

  onPage(event: Event) {
    clearTimeout(this.timeout);
    this.timeout = setTimeout(() => {
      console.log('paged!', event);
    }, 100);
  }

  toggleExpandRow(row) {
    console.log('Toggled Expand Row!', row);
    this.table.rowDetail.toggleExpandRow(row);
  }

  onDetailToggle(event) {
    console.log('Detail Toggled', event);
  }

  updateFilter(event) {
    const val = event.target.value.toLowerCase();
    this.rows = this.students.filter(row =>
      row.AspNetUsers.Nom.toLowerCase().indexOf(val) !== -1 || !val
    );
    this.table.offset = 0;
  }
}

like in the documentation code , I have to add a function to my input updateFilter that take the value of input and then there is a function that filter temporary array depending on the value inserted but this function doesn't work at all I get Cannot read property 'Name' of undefined I checked the value of they array using console and debug it seems the array is correct and have values but I don't know why the filter function returns nothing. I tried add try - catch the problem disappears but the filter function filter nothing.

EDIT : Code of student.component.html

<div class="container">
  <div class="row">
    <div class="col">
      <form>
        <div class="input-group">
          <input class="form-control" id="search"  name="search" (keyup)='updateFilter($event)' placeholder="Rechercher">
          <div class="input-group-addon"><i class="material-icons">search</i></div>
        </div>
      </form>
    </div>
  </div>
  <div class="row mt-3">
    <div class="col">
      <ngx-datatable
        #myTable
        class='material expandable'
        [columnMode]="'force'"
        [headerHeight]="50"
        [footerHeight]="50"
        [rowHeight]="50"
        [rows]='rows'
        [limit]="20"
        (page)="onPage($event)">

        <ngx-datatable-row-detail [rowHeight]="120" #myDetailRow (toggle)="onDetailToggle($event)">
          <ng-template let-row="row" let-expanded="expanded" ngx-datatable-row-detail-template>
            <div class="container">
              <table class="table">
                <tr>
                  <th>Email</th>
                  <td>{{row.AspNetUsers.Email}}</td>
                </tr>
                <tr>
                  <th>Adresse</th>
                  <td>{{row.ADRESSE}}</td>
                </tr>
              </table>
            </div>
          </ng-template>
        </ngx-datatable-row-detail>

        <ngx-datatable-column
          [width]="50"
          [resizeable]="false"
          [sortable]="false"
          [draggable]="false"
          [canAutoResize]="false">
          <ng-template let-row="row" let-expanded="expanded" ngx-datatable-cell-template>
            <a
              href="javascript:"
              [class.datatable-icon-right]="!expanded"
              [class.datatable-icon-down]="expanded"
              title="Expand/Collapse Row"
              (click)="toggleExpandRow(row)">
            </a>
          </ng-template>
        </ngx-datatable-column>

        <ngx-datatable-column name="ID" [width]="100">
          <ng-template let-row="row" ngx-datatable-cell-template>
            {{row.studentID}}
          </ng-template>
        </ngx-datatable-column>

        <ngx-datatable-column name="First Name" [width]="100">
          <ng-template let-row="row" ngx-datatable-cell-template>
            {{row.AspNetUsers.Name}}
          </ng-template>
        </ngx-datatable-column>

        <ngx-datatable-column name="Last Name" [width]="100">
          <ng-template let-row="row" ngx-datatable-cell-template>
            {{row.AspNetUsers.LastName}}
          </ng-template>
        </ngx-datatable-column>

        <ngx-datatable-column name="Special Code" [width]="100">
          <ng-template let-row="row" ngx-datatable-cell-template>
            {{row.AspNetUsers.SpecialCode}}
          </ng-template>
        </ngx-datatable-column>


        <ngx-datatable-column name="PhoneNumber" [width]="100">
          <ng-template let-row="row" ngx-datatable-cell-template>
            {{row.AspNetUsers.PhoneNumber}}
          </ng-template>
        </ngx-datatable-column>

      </ngx-datatable>
    </div>
  </div>
</div>

Edit 2 : I found out why I get the error , there is some missing names (they are null) and inside filter the problem happens if it's null. I added student !== null but still the problems happens.

Answer 1

It is obviously an error in the HTML which breaks your filtering. Put safe navigation operator into each interpolation of the row like:

{{row.AspNetUsers?.Name}}
{{row.AspNetUsers?.SpecialCode}}

And so on. Should remove the error, so you will able to debug more deeply.