Encountering an issue with the search/filter functionality in Angular Typescript

Question

Encountering an issue with the search/filter functionality in Angular Typescript

I need to locate a record by its ID using Angular TypeScript, and the array provided for this purpose is shown below

     {
  "products": [
    {
      "id": "1731002618",
      "imageUrl": "product_1.jpg",
      "brand": "Max Home Collection",
      "title": "5.2 cu. ft. High-Efficiency Stackable Front-Load Washer in White",
      "model": "7L12X165/8045CL",
      "rating": 3,
      "price1": 34.00,
      "cuom1": "case",
      "price2": 1.97,
      "cuom2": "sq. ft.",
      "saving": 22,
      "was": 41.48,
      "addToCart": "addToCart",
      "badges": [
        "badge-ECO",
        "badge-NLP",
        "badge-SB",
        "badge-ES"
      ]
    },
    ...
    }
  ]
}

The code I am working on looks like this

getProductByID(postid:string):Product {
    this.http.get<Product[]>(this.configUrl).subscribe(data => {
             this.product=data;    
    });
    
    // return this.http.get<Product[]>(this.configUrl);
    return { ...this.product.find(p=>p.id===postid) };
}

ngOnInit() { 
this.route.paramMap.subscribe((paramMap)=>{ 
    if(paramMap.has("postid")) { 
        alert('differentiate '+paramMap.get("postid"));
        alert('before call');
        var p = this.Service.getProductByID(paramMap.get("postid"))
                           .subscribe(data=>{ console.log(data);});
    }) 

}

However, I keep getting an error with the find function. Even when trying the filter function, the issue persists. Your assistance on this matter would be greatly appreciated.

angular typescript rxjs

Answer 1

Answer №1

Avoid enrolling in the provided service!

To retrieve product information using the getProductsByID() method, it is essential to define the HTTP call and data transformation required to obtain the desired format. The method should return an observable, allowing consumers of the service to subscribe accordingly.

Utilize the .pipe() method to manipulate the values within the stream by employing various operators, such as the map() operator to convert an array of products into a single product or undefined if the product does not exist.

service:

// Returns an observable stream that emits a single
// product (after fetching the complete product
// list and filtering down to one based on postid)

getProductByID(postid:string):Observable<Product|undefined> {
    return this.http.get<Product[]>(this.configUrl).pipe(
        map(products => products.find(p => p.id === postid))
    );
}

In the component, depending on the requirements, subscribing may not be necessary if you utilize the async pipe in the template. Define different observables$ for clarity.

Access the params as an observable source using ActivatedRoute.

component:

postid$: Observable<string>;
product$: Observable<Product>;

constructor(private route:ActivatedRoute) { }

ngOnInit() {
    // Emits the latest value of postid but doesn't emit if null/undefined.

    postid$ = route.params.pipe(
        map(p => p.postid),
        filter(p => !!p)
    );


    // Emits the latest value of product and uses postid$ to make the http call.

    product$ = postid$.pipe(
        switchMap(postid => this.Service.getProductByID(postid)),
        tap(product => console.log('product:', product))
    ); 
}

The tap operator can be used for side effects or logging purposes.

In the template:

<div *ngIf="product$ | async as product">
   <h1>{{ product.title }}</h1>
   <p>Model:{{ product.model }}</p>
   <p>Price:{{ product.price }}</p>
   <img src="{{ product.imageUrl }}">
</div>

The async pipe simplifies subscription management for you.

Answer 2

Avoid enrolling in the provided service!

To retrieve product information using the getProductsByID() method, it is essential to define the HTTP call and data transformation required to obtain the desired format. The method should return an observable, allowing consumers of the service to subscribe accordingly.

Utilize the .pipe() method to manipulate the values within the stream by employing various operators, such as the map() operator to convert an array of products into a single product or undefined if the product does not exist.

service:

// Returns an observable stream that emits a single
// product (after fetching the complete product
// list and filtering down to one based on postid)

getProductByID(postid:string):Observable<Product|undefined> {
    return this.http.get<Product[]>(this.configUrl).pipe(
        map(products => products.find(p => p.id === postid))
    );
}

In the component, depending on the requirements, subscribing may not be necessary if you utilize the async pipe in the template. Define different observables$ for clarity.

Access the params as an observable source using ActivatedRoute.

component:

postid$: Observable<string>;
product$: Observable<Product>;

constructor(private route:ActivatedRoute) { }

ngOnInit() {
    // Emits the latest value of postid but doesn't emit if null/undefined.

    postid$ = route.params.pipe(
        map(p => p.postid),
        filter(p => !!p)
    );


    // Emits the latest value of product and uses postid$ to make the http call.

    product$ = postid$.pipe(
        switchMap(postid => this.Service.getProductByID(postid)),
        tap(product => console.log('product:', product))
    ); 
}

The tap operator can be used for side effects or logging purposes.

In the template:

<div *ngIf="product$ | async as product">
   <h1>{{ product.title }}</h1>
   <p>Model:{{ product.model }}</p>
   <p>Price:{{ product.price }}</p>
   <img src="{{ product.imageUrl }}">
</div>

The async pipe simplifies subscription management for you.

Answer 3

Answer №2

If you attempt to execute the find operation on this.product before it is initialized, there will be an issue. Due to observables being asynchronous, the return will occur prior to the execution of this.product=data.

To resolve this, you must return it as an observable and subscribe to it elsewhere.

getProductByID(postid:string):Observable<Product> { // Uncertain whether this actually returns a product or not, it's an Observable of something...
   this.http.get<Product[]>(this.configUrl).pipe(map(data => {
       this.product=data; 
       return { ...this.product.find(p=>p.id===postid) };
   });
}

// When calling this method...
this.getProductByID('someId').subscribe(data => {
   // Result will be `{ ...this.product.find(p=>p.id===postid) };` 
  console.log(data);
})

Answer 4

If you attempt to execute the find operation on this.product before it is initialized, there will be an issue. Due to observables being asynchronous, the return will occur prior to the execution of this.product=data.

To resolve this, you must return it as an observable and subscribe to it elsewhere.

getProductByID(postid:string):Observable<Product> { // Uncertain whether this actually returns a product or not, it's an Observable of something...
   this.http.get<Product[]>(this.configUrl).pipe(map(data => {
       this.product=data; 
       return { ...this.product.find(p=>p.id===postid) };
   });
}

// When calling this method...
this.getProductByID('someId').subscribe(data => {
   // Result will be `{ ...this.product.find(p=>p.id===postid) };` 
  console.log(data);
})

Answer 5

Answer №3

To convert observables into promises, utilize the toPromise() method:

Handling in a Component


ngOnInit() { 
this.route.paramMap.subscribe((paramMap)=>{ 
    if(paramMap.has("postid")) { 
        alert('Processing '+paramMap.get("postid"));
        alert('Before making the call');
        const product = await this.Service.getProductByID(paramMap.get("postid"));
        console.log('The product is',product);
    }) 

}

The Service Method

async getProductByID(postid:string):Promise<Product>
   {
        const products = await this.http.get<Product[]>(this.configUrl).toPromise();

        return products.find(product=>product.id===postid);
   }

Answer 6

To convert observables into promises, utilize the toPromise() method:

Handling in a Component


ngOnInit() { 
this.route.paramMap.subscribe((paramMap)=>{ 
    if(paramMap.has("postid")) { 
        alert('Processing '+paramMap.get("postid"));
        alert('Before making the call');
        const product = await this.Service.getProductByID(paramMap.get("postid"));
        console.log('The product is',product);
    }) 

}

The Service Method

async getProductByID(postid:string):Promise<Product>
   {
        const products = await this.http.get<Product[]>(this.configUrl).toPromise();

        return products.find(product=>product.id===postid);
   }

Encountering an issue with the search/filter functionality in Angular Typescript

Answer №1

Answer №2

Answer №3

Handling in a Component

The Service Method

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