Angular 11 Tutorial: CRUD Application Example with REST Web API and Bootstrap 4
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Throughout this tutorial, We’ll be learning how to build an Angular 11 CRUD application with Bootstrap 4 styles to consume a REST Web API, create, read, modify and search data.
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Introducing our Angular 11 CRUD Application
We will learn how to build an Angular 11 front-end application that fetches data from a REST API of products:
- Each product has id, name, description, availability status.
- Users would be able to create, retrieve, update, and delete products.
- Users can search for products by name.
The REST API Endpoints
We’ll be building a Angular 11 frontend app for a presumed REST API exporting the following REST API endpoints:
- POST /api/products create new product
- GET /api/products retrieve all products
- GET /api/products/:id retrieve a product by
:id
- PUT /api/products/:id update a product by
:id
- DELETE /api/products/:id delete a product by
:id
- DELETE /api/products delete all products
- GET /api/products?name=[keyword] find all products which name contains the passed
keyword
.
All of them can work well with this Angular App.
Angular 11 CRUD App Structure
These are the components of our CRUD app:
- The
App
component is the parent of all other components and contains arouter-outlet
directive where the router will be inserting any matched component. It also contains a navigation bar that contains links to the app routes usingrouterLink
directive.
– ProductListComponent
which displays the list of products.– ProductUpdateComponent
which displays a form for editing product’s details by :id
.– ProductCreateComponent
which displays a form for creating a new product.
The components use the ProductService
methods for actually making CRUD operations against the REST API. The service makes use of Angular 11 HTTPClient
to send HTTP requests to the REST and process responses.
Step 1 — Creating a New Angular 11 Project
Let’s get started by generating a new Angular 11 project using the CLI. You need to run the following command:
$ ng new Angular11CRUDExample
The CLI will ask you a couple of questions — If Would you like to add Angular routing? Type y for Yes and Which stylesheet format would you like to use? Choose CSS.
Step 2 — Generating Angular 11 CRUD Components and Service
Next, we need to generate a bunch of components and a service using the Angular CLI as follows:
$ ng generate service services/product$ ng g c components/product-create$ ng g c components/product-details$ ng g c components/product-list
We have generated three components product-list
, product-details
, product-create
and a product service that provides the necessary methods for sending HTTP requests to the server.
We also have the following artifacts:
– The src/app/app-routing.module.ts
module will contain routes for each component. This file is automatically generated by Angular CLI when you answered Yes for routing.– The App
component contains the router view and navigation bar.– The src/app/app.module.ts
module declares our Angular components and import the necessary modules such Angular HttpClient
.
Step 3 — Importing FormsModule
and HttpClientModule
We’ll be using the http client and forms in our CRUD application which are provided in its own modules in Angular so we’ll need to import these modules — FormsModule
and HttpClientModule
.
Open src/app/app.module.ts
file and import FormsModule
, HttpClientModule
as follows:
// [...]import{FormsModule}from'@angular/forms';import{HttpClientModule}from'@angular/common/http';@NgModule({declarations:[...],imports:[...FormsModule,HttpClientModule],providers:[],bootstrap:[AppComponent]})exportclassAppModule{}
Step 4 — Adding Routes for the CRUD Components
We have the components that compose our application UI but we need to link them with their routes to be able to navigate between them using the Angular 11 Router.
We’ll create three routes:
– /products
for the product-list
component, – /products/:id
for the product-details
component, – /create
for theproduct-create
component.
Open the src/app/app-routing.module.ts
file and update it as follows:
import{NgModule}from'@angular/core';import{Routes,RouterModule}from'@angular/router';import{ProductListComponent}from'./components/product-list/product-list.component';import{ProductDetailsComponent}from'./components/product-details/product-details.component';import{ProductCreateComponent}from'./components/product-create/product-create.component';constroutes:Routes=[{path:'',redirectTo:'products',pathMatch:'full'},{path:'products',component:ProductListComponent},{path:'products/:id',component:ProductDetailsComponent},{path:'create',component:ProductCreateComponent}];@NgModule({imports:[RouterModule.forRoot(routes)],exports:[RouterModule]})exportclassAppRoutingModule{}
Step 5 — Adding and Styling a Navigation Bar Using Bootstrap 4
Next, let’s add Bootstrap 4 to our application and a navigation bar.
We’ll be using Bootstrap 4 for styling the UI so you’ll need to install it in your project. Check out three ways for how to add bootstrap to your Angular project.
Open the src/app/app.component.html
file, and update as follows:
<div> <nav > <a href="#" >Techiediaries</a> <div > <li > <a routerLink="products" >Products</a> </li> <li > <a routerLink="create" >Create</a> </li> </div> </nav> <div > <router-outlet></router-outlet> </div></div>
We have created a bootstrap navigation bar and wrapped the router outlet with a container div.
Step 6 — Creating an Angular 11 CRUD Service
Next, we need to create a CRUD service that will use Angular 11 HTTPClient
to send HTTP requests to the REST API server.
Open the src/services/product.service.ts
file and update it as follows:
import{Injectable}from'@angular/core';import{HttpClient}from'@angular/common/http';import{Observable}from'rxjs';constbaseURL='http://localhost:8080/api/products';@Injectable({providedIn:'root'})exportclassProductService{constructor(privatehttpClient:HttpClient){}readAll():Observable<any>{returnthis.httpClient.get(baseURL);}read(id):Observable<any>{returnthis.httpClient.get('${baseURL}/${id}');}create(data):Observable<any>{returnthis.httpClient.post(baseURL,data);}update(id,data):Observable<any>{returnthis.httpClient.put('${baseURL}/${id}', data);}delete(id):Observable<any>{returnthis.httpClient.delete('${baseURL}/${id}');}deleteAll():Observable<any>{returnthis.httpClient.delete(baseURL);}searchByName(name):Observable<any>{returnthis.httpClient.get('${baseURL}?name=${name}');}}
Step 7 — Implementing the Angular 11 CRUD Components
We have previously generated three components and added them to the router, let’s now implement the actual functionality of each component.
Creating a New Product Component
This component provides a form for submitting a new product with two fields, name
and description
. It injects and calls the ProductService.create()
method.
Open the src/components/product-create/product-create.component.ts
file and update it as follows:
import{Component,OnInit}from'@angular/core';import{ProductService}from'src/app/services/product.service';@Component({selector:'app-product-create',templateUrl:'./product-create.component.html',styleUrls:['./product-create.component.css']})exportclassProductCreateComponentimplementsOnInit{product={name:'',description:'',available:false};submitted=false;constructor(privateproductService:ProductService){}ngOnInit():void{}createProduct():void{constdata={name:this.product.name,description:this.product.description};this.productService.create(data).subscribe(response=>{console.log(response);this.submitted=true;},error=>{console.log(error);});}newProduct():void{this.submitted=false;this.product={name:'',description:'',available:false};}}
Next, open the src/components/product-create/product-create.component.html
file and update it as follows:
<div style="width: 500px; margin: auto;"> <div > <div *ngIf="!submitted"> <div > <label for="name">Name</label> <input type="text" id="name" required [(ngModel)]="product.name" name="name" /> </div> <div > <label for="description">Description</label> <input id="description" required [(ngModel)]="product.description" name="description" /> </div> <button (click)="createProduct()" >Create</button> </div> <div *ngIf="submitted"> <h3>You successfully created a product!</h3> <button (click)="newProduct()">New..</button> </div> </div></div>
Displaying the List of Products Component
Next, let’s implement the product list component, which makes use of the following service methods:
readAll()
deleteAll()
searchByName()
Open the src/components/product-list/product-list.component.ts
file and update it as follows:
import{Component,OnInit}from'@angular/core';import{ProductService}from'src/app/services/product.service';@Component({selector:'app-product-list',templateUrl:'./product-list.component.html',styleUrls:['./product-list.component.css']})exportclassProductListComponentimplementsOnInit{products:any;currentProduct=null;currentIndex=-1;name='';constructor(privateproductService:ProductService){}ngOnInit():void{this.readProducts();}readProducts():void{this.productService.readAll().subscribe(products=>{this.products=products;console.log(products);},error=>{console.log(error);});}refresh():void{this.readProducts();this.currentProduct=null;this.currentIndex=-1;}setCurrentProduct(product,index):void{this.currentProduct=product;this.currentIndex=index;}deleteAllProducts():void{this.productService.deleteAll().subscribe(response=>{console.log(response);this.readProducts();},error=>{console.log(error);});}searchByName():void{this.productService.searchByName(this.name).subscribe(products=>{this.products=products;console.log(products);},error=>{console.log(error);});}}
Open the src/components/product-list/product-list.component.html
file and update it as follows:
<div > <div > <div > <input type="text" placeholder="Search by name" [(ngModel)]="name" /> <div > <button type="button" (click)="searchByName()" > Search </button> </div> </div> </div> <div > <h4>Product List</h4> <ul > <li *ngFor="let product of products; let i = index" [class.active]="i == currentIndex" (click)="setCurrentProduct(product, i)" > </li> </ul> <button (click)="deleteAllProducts()"> Delete All </button> </div> <div > <div *ngIf="currentProduct"> <h4>Product</h4> <div> <label><strong>Name:</strong></label> </div> <div> <label><strong>Description:</strong></label> </div> <div> <label><strong>Status:</strong></label> </div> <a routerLink="/products/"> Edit </a> </div> <div *ngIf="!currentProduct"> <br /> Please click on a product</p> </div> </div></div>
If you click on Edit button of any product, you will be directed to the product details page with the /products/:id
URL.
The Product Details Component
Next, let’s implement the product details component of our Angular 11 CRUD application.
Open the src/components/product-details/product-details.component.ts
file and update it as follows:
import{Component,OnInit}from'@angular/core';import{ProductService}from'src/app/services/product.service';import{ActivatedRoute,Router}from'@angular/router';@Component({selector:'app-product-details',templateUrl:'./product-details.component.html',styleUrls:['./product-details.component.css']})exportclassProductDetailsComponentimplementsOnInit{currentproduct=null;message='';constructor(privateproductService:ProductService,privateroute:ActivatedRoute,privaterouter:Router){}ngOnInit():void{this.message='';this.getProduct(this.route.snapshot.paramMap.get('id'));}getProduct(id):void{this.productService.read(id).subscribe(product=>{this.currentProduct=product;console.log(product);},error=>{console.log(error);});}setAvailableStatus(status):void{constdata={name:this.currentProduct.name,description:this.currentProduct.description,available:status};this.productService.update(this.currentProduct.id,data).subscribe(response=>{this.currentProduct.available=status;console.log(response);},error=>{console.log(error);});}updateProduct():void{this.productService.update(this.currentProduct.id,this.currentProduct).subscribe(response=>{console.log(response);this.message='The product was updated!';},error=>{console.log(error);});}deleteProduct():void{this.productService.delete(this.currentProduct.id).subscribe(response=>{console.log(response);this.router.navigate(['/products']);},error=>{console.log(error);});}}
Open the src/components/product-details/product-details.component.html
file and update it as follows:
<div style="width: 500px; margin: auto;"> <div *ngIf="currentProduct" > <h4>Product</h4> <form> <div > <label for="title">Name</label> <input type="text" id="name" [(ngModel)]="currentProduct.name" name="name" /> </div> <div > <label for="description">Description</label> <input type="text" id="description" [(ngModel)]="currentProduct.description" name="description" /> </div> <div > <label><strong>Status:</strong></label> </div> </form> <button *ngIf="currentProduct.available" (click)="setAvailableStatus(false)" > Set Not Available </button> <button *ngIf="!currentProduct.available" (click)="setAvailableStatus(true)" > Set Available </button> <button (click)="deleteProduct()"> Delete </button> <button type="submit" (click)="updateProduct()" > Update </button> </p> </div> <div *ngIf="!currentProduct"> <br /> This product is not accessible</p> </div></div>
Step 8 — Serving the Angular 11 CRUD App
Head back to your command-line interface, make sure your are navigated at the root of your project’s directory and run the following command to start a live development server in your local machine:
$ cd Angular11CRUDExample$ ng serve
Go to your web browser and navigate to the http://localhost:4200/
address to start testing your app.
Conclusion
In this tutorial, we’ve built an Angular 11 CRUD application for a Web REST API and we used Bootstrap 4 for styling the UI.
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