Optimal method for accessing params and queryParams in Angular 2

Question

Optimal method for accessing params and queryParams in Angular 2

Seeking insights on how to craft a route with information stored in its URL parameters.

Here's an example of my route (app.routes.ts):

{path: 'results/:id', component: MyResultsComponent},

How I navigate to the route :

goToResultsPage(query: string) {
this.router.navigate(['results', query], { queryParams: { pageSize: 20 } });}

Additionally, there is a query parameter. I'm pondering on the most efficient and elegant way to retrieve this in my MyResultsComponent. Currently, I have a sort of nested subscribe structure:

ngOnInit() {
    this.route
      .params
      .subscribe(params => {
        this.query = params['id'];
        this.route
          .queryParams
          .subscribe(queryParams => {
            this.offset = queryParams['pageSize'];
            #find entries this.entryService.findEntries(this.query, this.pageSize);
      });
    });
  }

Subsequently, I aim to pass these parameters to my EntryService to fetch the entries found.

angular typescript angular2-routing

Answer 1

Answer №1

Could using Observable.combineLatest be the answer to this particular issue?

Observable
  .combineLatest(
    this.router.events,
    this.router.queryParams,
    (events: any, queryParams: any) => {
      return {
        event: events.type,
        page: queryParams.page ? +queryParams.page : null
      }
    })
  .subscribe(mergedData => {
    this.eventType = mergedData.event;
    this.pageNumber = mergedData.page;
  });

Answer 2

Could using Observable.combineLatest be the answer to this particular issue?

Observable
  .combineLatest(
    this.router.events,
    this.router.queryParams,
    (events: any, queryParams: any) => {
      return {
        event: events.type,
        page: queryParams.page ? +queryParams.page : null
      }
    })
  .subscribe(mergedData => {
    this.eventType = mergedData.event;
    this.pageNumber = mergedData.page;
  });

Answer 3

Answer №2

It seems like using the snapshot is the best choice when you need to access both elements simultaneously.

Keep in mind that this code snippet has not been tested, it's just an idea I came up with on the spot.

ngOnInit() {
    this.route
      .params
      .subscribe(params => {
        this.query = params['id'];
        this.offset = this.route.snapshot.queryParams['pageSize'];
        // find entries this.entryService.findEntries(this.query, this.pageSize);
      });
    });
  }

Answer 4

It seems like using the snapshot is the best choice when you need to access both elements simultaneously.

Keep in mind that this code snippet has not been tested, it's just an idea I came up with on the spot.

ngOnInit() {
    this.route
      .params
      .subscribe(params => {
        this.query = params['id'];
        this.offset = this.route.snapshot.queryParams['pageSize'];
        // find entries this.entryService.findEntries(this.query, this.pageSize);
      });
    });
  }

Answer 5

Answer №3

Have you considered using ForkJoin?

ForkJoin allows you to combine two observables and wait for both responses. For more information, you can check out the documentation here and learn more about it here.

In your code, it would be implemented like this:

ngOnInit() {
    Observable.forkJoin(this.route.params, this.route.queryParams).subscribe(bothParams => {
        // bothParams is an array, with the router.params in the first index 
        // and the queryParams in the second index
        this.query = bothParams[0].query;
        this.pageSize = bothParams[0].pageSize;
        this.entryService.findEntries(this.query, this.pageSize);
    });
  }

Don't forget to import the necessary modules:

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/forkJoin';

Answer 6

Have you considered using ForkJoin?

ForkJoin allows you to combine two observables and wait for both responses. For more information, you can check out the documentation here and learn more about it here.

In your code, it would be implemented like this:

ngOnInit() {
    Observable.forkJoin(this.route.params, this.route.queryParams).subscribe(bothParams => {
        // bothParams is an array, with the router.params in the first index 
        // and the queryParams in the second index
        this.query = bothParams[0].query;
        this.pageSize = bothParams[0].pageSize;
        this.entryService.findEntries(this.query, this.pageSize);
    });
  }

Don't forget to import the necessary modules:

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/forkJoin';

Answer 7

Answer №4

Recently, I encountered a dilemma and after some exploration, I discovered that the most suitable solution for my situation was using Observable.merge.

If you are looking to monitor changes from params or queryParams within the same component (such as searching with filters), using snapshot is not the most effective approach.

Observable.forkJoin poses a limitation where both observables have to be triggered for it to function. So, if there is a possibility of changes in either params or queryParams, but not necessarily in both, forkJoin would not be the ideal choice.

However, with Observable.merge, it can be triggered with just one of them being activated. Although, this method also comes with some drawbacks like the potential for two callbacks to be triggered consecutively (initially with params and queryParams).

Here's an illustration:

Observable.merge(
  this.route.params.map(params => this.handleParams(params)),
  this.route.queryParams.map(queryParams => this.handleQueryParams(queryParams))
)
.subscribe(
  () => this.onParamsOrQueryParamsChange()
);

Answer 8

Recently, I encountered a dilemma and after some exploration, I discovered that the most suitable solution for my situation was using Observable.merge.

If you are looking to monitor changes from params or queryParams within the same component (such as searching with filters), using snapshot is not the most effective approach.

Observable.forkJoin poses a limitation where both observables have to be triggered for it to function. So, if there is a possibility of changes in either params or queryParams, but not necessarily in both, forkJoin would not be the ideal choice.

However, with Observable.merge, it can be triggered with just one of them being activated. Although, this method also comes with some drawbacks like the potential for two callbacks to be triggered consecutively (initially with params and queryParams).

Here's an illustration:

Observable.merge(
  this.route.params.map(params => this.handleParams(params)),
  this.route.queryParams.map(queryParams => this.handleQueryParams(queryParams))
)
.subscribe(
  () => this.onParamsOrQueryParamsChange()
);

Answer 9

Answer №5

Here is a suggested solution:

Give this a shot:

setTimeout(() => {
  this.route.queryParams
    .subscribe((params: Params) => {
      console.log('PARAMS',params);
      }
    });
},0);

Answer 10

Here is a suggested solution:

Give this a shot:

setTimeout(() => {
  this.route.queryParams
    .subscribe((params: Params) => {
      console.log('PARAMS',params);
      }
    });
},0);

Answer 11

Answer №6

2023

However, there may still be challenges for certain individuals.

In my experience, I discovered that in your app.component, you should implement the following:

this._router.events.pipe(startWith(this._router)).subscribe((event) => {
    let queryparams;
    let url; 
    if (event instanceof ActivationEnd) {
        queryparams = event.snapshot.queryparams;
    }
    if (event instanceof NavigationEnd) {
        SomeService.routevent.next({url:event.url,queryparams:queryparams});
    }
});

Establish a service and assign it a BehaviorSubject routevent. This way, you can easily access the most up-to-date url or queryparams in any component or location.

Answer 12

2023

However, there may still be challenges for certain individuals.

In my experience, I discovered that in your app.component, you should implement the following:

this._router.events.pipe(startWith(this._router)).subscribe((event) => {
    let queryparams;
    let url; 
    if (event instanceof ActivationEnd) {
        queryparams = event.snapshot.queryparams;
    }
    if (event instanceof NavigationEnd) {
        SomeService.routevent.next({url:event.url,queryparams:queryparams});
    }
});

Establish a service and assign it a BehaviorSubject routevent. This way, you can easily access the most up-to-date url or queryparams in any component or location.

Optimal method for accessing params and queryParams in Angular 2

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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