ngx-pagination-angular-8-server-side-pagination-feature-image

Angular 8 Pagination example | ngx-pagination Server-side

In this tutorial, I will show you how to make Pagination in an Angular 8 Application with existing API (server-side pagination) using ngx-pagination.

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Angular 8 CRUD Application example with Web API
Angular 8 JWT Auth – Token based Authentication with Web Api example
Angular 8 Multiple Files upload example


Pagination in Angular 8 example

One of the most important things to make a website friendly is the response time, and pagination comes for this reason. For example, this bezkoder.com website has hundreds of tutorials, and we don’t want to see all of them at once. Paging means displaying a small number of all, by a page.

Assume that we have tutorials table in database like this:

ngx-pagination-angular-8-example-database

Our Angular 8 app will display the result with pagination:

ngx-pagination-angular-8-default-paging

You can change to a page with larger index:

ngx-pagination-angular-8-change-page

Or change quantity of items per page:

ngx-pagination-angular-8-change-items-per-page

Or paging with filter:

ngx-pagination-angular-8-paging-filter

The API for this Angular client can be found at one of following posts:
Node.js Express Pagination with MySQL
Node.js Express Pagination with PostgreSQL
Node.js Express Pagination with MongoDB
Spring Boot Pagination & Filter example | Spring JPA, Pageable
Spring Boot MongoDB Pagination example with Spring Data

These Servers will exports API for pagination (with/without filter), here are some url samples:

  • /api/tutorials?page=1&size=5
  • /api/tutorials?size=5: using default value for page
  • /api/tutorials?page=1: using default value for size
  • /api/tutorials?title=data&page=1&size=3: pagination & filter by title containing ‘data’

This is structure of the response (server-side pagination) for the HTTP GET request:

{
    "totalItems": 8,
    "tutorials": [...],
    "totalPages": 3,
    "currentPage": 1
}

This is a kind of server-side paging, where the server sends just a single page at a time. ngx-pagination supports this scenario, so We actually only need to use tutorials and totalItems when working with this library.

How to use ngx-pagination

ngx-pagination provides NgxPaginationModule for displaying pagination with numbers and responsive style.

There are 2 main things that we’re gonna use:

  • PaginatePipe: placed at the end of an ngFor expression
  • <your-element *ngFor="let item of collection | paginate: { id: 'foo',
                                                          itemsPerPage: pageSize,
                                                          currentPage: page,
                                                          totalItems: total }">...</your-element>
    

    Use the id if you need to support more than one instance of pagination at a time.

  • PaginationControlsComponent: a default component for displaying pagination controls
  • <pagination-controls></pagination-controls>
    

For example, this is the default display for simple pagination-controls above:

ngx-pagination-angular-8-default-pagination-controls

We can customize the label displayed on the “previous”/”next” link using previousLabel/nextLabel, and enable “responsive” to hide individual page links on small screens.

<pagination-controls
  previousLabel="Prev"
  nextLabel="Next"
  responsive="true"
></pagination-controls>

ngx-pagination-angular-8-customize-pagination-controls

For handling page changes, we pass handlePageChange to pageChange.
Notice that count is totalItems in the API response, and page is the current page.

<pagination-controls
  (pageChange)="handlePageChange($event)"
></pagination-controls>

<ul>
  <li
    *ngFor="let tutorial of tutorials | paginate: {
              itemsPerPage: pageSize,
              currentPage: page,
              totalItems: count
            }"
  >
    {{ tutorial.title }}
  </li>
</ul>
@Component(...)
export class TutorialsListComponent {
  ...
  page = 1;

  handlePageChange(event) {
    this.page = event;
  }

}

pageChange is the expression invoked whenever the page changes via a click on the pagination controls. The $event argument will be the number of the new page.

There are more attributes that ngx-pagination supports:

<pagination-controls  id="some_id"
                      (pageChange)="pageChanged($event)"
                      (pageBoundsCorrection)="pageChanged($event)"
                      maxSize="9"
                      directionLinks="true"
                      autoHide="true"
                      responsive="true"
                      previousLabel="Previous"
                      nextLabel="Next"
                      screenReaderPaginationLabel="Pagination"
                      screenReaderPageLabel="page"
                      screenReaderCurrentLabel="You're on page">
</pagination-controls>

You can find the details at: https://www.npmjs.com/package/ngx-pagination.

Technology

  • Angular 8
  • RxJS 6
  • ngx-pagination 5

Setup Angular 8 Application

Let’s open cmd and use Angular CLI to create a new Angular Project as following command:

ng new Angular8PaginationExample
? Would you like to add Angular routing? Yes
? Which stylesheet format would you like to use? CSS

We also need to generate some Components and Services:

ng g s services/tutorial

ng g c components/add-tutorial
ng g c components/tutorial-details
ng g c components/tutorials-list

Now you can see that our project directory structure looks like this.


src

app

components

add-tutorial

tutorial-details

tutorials-list

services

tutorial.service.ts

app.routing.module

app.component.html

app.component.ts

index.html

package.json


You can follow step by step, or get source code in this post:
Angular 8 CRUD Application example with Web API

The Angular Project contains structure that we only need to add some changes (in tutorials-list component and tutorial.service.ts) to make the pagination work well.

ngx-pagination-angular-8-project-structure

Or you can get the new Github source code at the end of this tutorial.

Setup ngx-pagination for Angular 8 Pagination App

We need to install ngx-pagination with command:
npm install ngx-pagination --save

Then open app.module.ts and import it:

...
import { HttpClientModule } from '@angular/common/http';
import { NgxPaginationModule } from 'ngx-pagination';

@NgModule({
  declarations: [ ... ],
  imports: [
    ...
    NgxPaginationModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Create Data Service

This service will use Angular HTTPClient to send HTTP requests.

services/tutorial.service.ts

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

const baseUrl = 'http://localhost:8080/api/tutorials';

@Injectable({
  providedIn: 'root'
})
export class TutorialService {

  constructor(private http: HttpClient) { }

  getAll(params): Observable {
    return this.http.get(baseUrl, { params });
  }

  // other CRUD methods
}

In the code above, you can see that we pass params object to GET method.
The params object will have one, two or all fields: title, page, size.

Create Angular 8 Components with Pagination

This component has:

  • a search bar for finding Tutorials by title.
  • a select element for quantity of items per page.
  • a PaginationControlsComponent component
  • a tutorials array displayed as a list on the left.
  • a selected Tutorial which is shown on the right.

ngx-pagination-angular-8-default-paging

components/tutorials-list/tutorials-list.component.html

<div class="list row">
  <div class="col-md-8">
    <div class="input-group mb-3">
      <input
        type="text"
        class="form-control"
        placeholder="Search by title"
        [(ngModel)]="title"
      />
      <div class="input-group-append">
        <button
          class="btn btn-outline-secondary"
          type="button"
          (click)="retrieveTutorials()"
        >
          Search
        </button>
      </div>
    </div>
  </div>

  <div class="col-md-12">
    <pagination-controls
      previousLabel="Prev"
      nextLabel="Next"
      responsive="true"
      (pageChange)="handlePageChange($event)"
    ></pagination-controls>
  </div>

  <div class="col-md-6">
    <h4>Tutorials List</h4>

    <ul class="list-group">
      <li
        class="list-group-item"
        *ngFor="
          let tutorial of tutorials | paginate : {
                  itemsPerPage: pageSize,
                  currentPage: page,
                  totalItems: count
                };
          let i = index
        "
        [class.active]="i == currentIndex"
        (click)="setActiveTutorial(tutorial, i)"
      >
        {{ tutorial.title }}
      </li>
    </ul>
  </div>
  ...

  <div class="mt-3">
    ...

    Items per Page:
    <select (change)="handlePageSizeChange($event)">
      <option *ngFor="let size of pageSizes" [ngValue]="size">
        {{ size }}
      </option>
    </select>
  </div>
</div>

We will have following variables:
– search and display Tutorials:

  • title
  • tutorials
  • currentTutorial and currentIndex

– pagination:

  • page: current page
  • count: total pages
  • pageSize: number of items in each page

For pagination, we’re gonna use TutorialService.getAll() methods.

components/tutorials-list/tutorials-list.component.ts

import { Component, OnInit } from '@angular/core';
import { TutorialService } from 'src/app/services/tutorial.service';

@Component({
  selector: 'app-tutorials-list',
  templateUrl: './tutorials-list.component.html',
  styleUrls: ['./tutorials-list.component.css']
})
export class TutorialsListComponent implements OnInit {

  tutorials: any;
  currentTutorial = null;
  currentIndex = -1;
  title = '';

  page = 1;
  count = 0;
  pageSize = 3;
  pageSizes = [3, 6, 9];

  constructor(private tutorialService: TutorialService) { }

  ngOnInit() {
    this.retrieveTutorials();
  }

  getRequestParams(searchTitle, page, pageSize) {
    // tslint:disable-next-line:prefer-const
    let params = {};

    if (searchTitle) {
      params[`title`] = searchTitle;
    }

    if (page) {
      params[`page`] = page - 1;
    }

    if (pageSize) {
      params[`size`] = pageSize;
    }

    return params;
  }

  retrieveTutorials() {
    const params = this.getRequestParams(this.title, this.page, this.pageSize);

    this.tutorialService.getAll(params)
      .subscribe(
        response => {
          const { tutorials, totalItems } = response;
          this.tutorials = tutorials;
          this.count = totalItems;
          console.log(response);
        },
        error => {
          console.log(error);
        });
  }

  handlePageChange(event) {
    this.page = event;
    this.retrieveTutorials();
  }

  handlePageSizeChange(event) {
    this.pageSize = event.target.value;
    this.page = 1;
    this.retrieveTutorials();
  }

  ...
}

Let me explain some lines of code.

In the retrieveTutorials() method:
– We get title, page, pageSize value and transform them into params object:

{
    "title": searchTitle,
    "page": page - 1,
    "size": pageSize
}

– We use tutorials and totalItems as count value from the response data:

{
    "totalItems": 8,
    "tutorials": [...],
    "totalPages": 3,
    "currentPage": 1
}

handlePageChange() and handlePageSizeChange() methods are for setting new page and pageSize, then we invoke retrieveTutorials() that updates the tutorials List when pagination information changes.

Run Angular 8 Pagination App

First you need to run the Server at one of following posts:

Then you can run our App with command: ng serve --port 8081.
If the process is successful, open Browser with Url: http://localhost:8081/ and check it.

Conclusion

Today we’ve built a Angular 8 Pagination example that consume API (server-side pagination) successfully with ngx-pagination. I hope you apply it in your project at ease.

Happy learning, see you again!

Further Reading

Source Code

You can find the complete source code for this tutorial on Github.

3 thoughts to “Angular 8 Pagination example | ngx-pagination Server-side”

    1. Hi, it is in the source code (tutorials-list.component.ts) that you can find in github.
      I don’t write the function in this tutorial because it’s not necessary for Pagination purpose of the tutorial.

  1. can we take data recursively from api which can take less time to load data and on click of paging data of each page loads.. please share if you have any example for this scenario.

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