How to use server side option in Angular DataTables with the Angular way example?

Question

I'm trying to use Angular DataTables with the server side processing option, but when I try to enable it in their "Angular way example", only the first request gets rendered, the subsequent requests (paging, ordering, searching) are sent but they never update the table.

Answer 1

After a little digging, I found an unrelated user contributed note that suggests that you override the ajax option with your own function to handle the server side call.

The trick here is to return an empty array to the DataTables callback, so it won't use its renderer to render the table. That will be done by Angular. It's also a good idea to specify the columns names to the server.

ngOnInit(): void {
    var that = this;

    this.dtOptions = {
        pagingType: 'full_numbers',
        serverSide: true,
        processing: true,
        ajax: (dataTablesParameters: any, callback) => {
            that.http
                .post<DataTablesResponse>('/api/Persons', dataTablesParameters, {})
                .subscribe(resp => {
                    that.persons = resp.data;

                    callback({
                        recordsTotal: resp.recordsTotal,
                        recordsFiltered: resp.recordsFiltered,
                        data: [],
                    });
                });
        },
        columns: [
            { data: "id" },
            { data: "firstName" },
            { data: "lastName" },
        ],
    };
}

Since DataTables will think there are no rows to display, it will show the "No data available" message. The simplest way to handle it is to hide it with CSS. You can add it to your global styles.css:

.dataTables_empty {
    display: none;
}

then show it yourself in the template:

<tr *ngIf="persons?.length == 0">
    <td colspan="3" class="no-data-available">No data!</td>
</tr>

So here's the complete code. Tested with Angular 5.0.0, datatables.net 1.10.16 and angular-datatables 5.0.0:

angular-way-server-side.component.ts

import { Component, OnInit } from '@angular/core';
import { HttpClient, HttpResponse } from '@angular/common/http';
import { DataTablesResponse } from '../datatables/datatables-response';
import { Person } from './person';

@Component({
    selector: 'app-angular-way-server-side',
    templateUrl: 'angular-way-server-side.component.html',
    styleUrls: ['angular-way-server-side.component.css'],
})
export class AngularWayServerSideComponent implements OnInit {
    dtOptions: DataTables.Settings = {};
    persons: Person[];

    constructor(private http: HttpClient) { }

    ngOnInit(): void {
        var that = this;

        this.dtOptions = {
            pagingType: 'full_numbers',
            serverSide: true,
            processing: true,
            ajax: (dataTablesParameters: any, callback) => {
                that.http
                    .post<DataTablesResponse>('/api/Persons', dataTablesParameters, {})
                    .subscribe(resp => {
                        that.persons = resp.data;

                        callback({
                            recordsTotal: resp.recordsTotal,
                            recordsFiltered: resp.recordsFiltered,
                            data: [],
                        });
                    });
            },
            columns: [
                { data: "id" },
                { data: "firstName" },
                { data: "lastName" },
            ],
        };
    }
}

angular-way-server-side.component.html

<table datatable [dtOptions]="dtOptions" class="row-border hover">
    <thead>
        <tr>
            <th>ID</th>
            <th>First name</th>
            <th>Last name</th>
        </tr>
    </thead>
    <tbody>
        <tr *ngFor="let person of persons">
            <td>{{ person.id }}</td>
            <td>{{ person.firstName }}</td>
            <td>{{ person.lastName }}</td>
        </tr>
        <tr *ngIf="persons?.length == 0">
            <td colspan="3" class="no-data-available">No data!</td>
        </tr>
    </tbody>
</table>

angular-way-server-side.component.css

.no-data-available {
    text-align: center;
}

person.ts

export class Person {
    id: number;
    firstName: string;
    lastName: string;
}

datatables-response.ts

export class DataTablesResponse {
    data: any[];
    draw: number;
    recordsFiltered: number;
    recordsTotal: number;
}

src/styles.css

.dataTables_empty {
    display: none;
}

---

The server side is implemented pretty much the same way as if you were using DataTables with JavaScript/jQuery. You can see a very simple sample implementation in PHP.