Develop Reference

To get Id for edit functionality in angular

I have created a popup for edit functionality in my todo app and I need to get the id of the task for the purpose. using route is not giving a correct result. Is there any other way I can achieve it? I have given the code below.
this.id = this.route.snapshot.params['id'];
console.log(this.formData.value);
this.todoService.editTasks(this.id, this.formData.value).subscribe((res: any)=>{
console.log('update successful');
// this.router.navigateByUrl('/tasks');
})
}```

verfiy that you have the same id in the path of edit component :
{path: "edit/:id", component: someComponent}
use that in the component
import { ActivatedRoute } from '#angular/router';
constructor(private route: ActivatedRoute) {}
ngOnInit(){
//you need to unsubscribe in the ngOnDestroy
this.subscription = this.route.paramMap.subscribe(params=> {
//i use + to convert the id to a number type
let id =+params.get('id');
}
//To prevent memory leak
ngOnDestroy(): void {
if (this.subscription)
this.subscription.unsubscribe()
}
or use that :
ngOnInit(){
let id =this.route.snapshot.paramMap.get('id');
}
use the Angular doc : https://angular.io/tutorial/toh-pt5#extract-the-id-route-parameter

You need to use ActivatedRoute in order to get the id from the URL, check the following steps to use it.
// import
import { ActivatedRoute } from '#angular/router';
//dependency injection
constructor(private route: ActivatedRoute) { }
//implementation
ngOnInit() {
this.route.paramMap.subscribe(
params => {
this.id= params.get('id'); // This is the required Id
})
}
I hope this answers your question, Let me know if I got something wrong.

In Angular 9, how do I update a component's data field to show in the DOM without re-instantiating it?

I'm fairly new to Angular 9. I have a program where a user enters in a name - which, upon submitting - a POST HTTP request is sent and the name is stored. I then have an unrelated component for a sub-header that lists the names that have been stored using a GET HTTP request using ngOnInit(). However, I need the sub-header to update that list of names dynamically each time a new list is entered rather than just whenever the component instantiates.
I'm unsure how to proceed. I'm sure I could simply add a button that fetches and updates said list, but trying for something more dynamic. Thanks in advance!
//SERVICE.TS...
import { Injectable } from '#angular/core';
import { HttpClient } from '#angular/common/http';
import { NewList } from './new-list.model';
import { map } from 'rxjs/operators';
#Injectable({
providedIn: 'root'
})
export class ListService {
createdLists: NewList[] = [];
constructor(private http: HttpClient) { }
createList(postData) {
return this.http
.post(
'API_KEY',
postData
);
}
getLists() {
return this.http
.get<NewList>(
'API_KEY'
).pipe(map(responseData => {
const responseArray: NewList[] = [];
for (const key in responseData) {
responseArray.push(responseData[key])
}
return responseArray;
})
);
}
}
// NEW-LIST-MENU.TS (USER ENTERS A NAME)...
import { Component, OnInit } from '#angular/core';
import { NgForm } from '#angular/forms';
import { Router } from '#angular/router';
import { ListService } from 'src/app/shared/list.service';
import { NewList } from 'src/app/shared/new-list.model';
import { UIService } from 'src/app/shared/ui.service';
#Component({
selector: 'app-new-list-menu',
templateUrl: './new-list-menu.component.html',
styleUrls: ['./new-list-menu.component.css']
})
export class NewListMenuComponent implements OnInit {
constructor(private listService: ListService,
private uiService: UIService,
private router: Router) { }
ngOnInit(): void {
}
onSubmit(form: NgForm) {
const listName = form.value.listname;
const newListObj = new NewList(listName, []);
this.listService.createList(newListObj)
.subscribe(() => {
this.router.navigate(['']);
});
const lists = this.listService.updateLists(newListObj);
form.reset();
}
onCancel() {
this.router.navigate(['']);
}
}
// SUB-HEADER.TS...
import { Component, OnInit, Output } from '#angular/core';
import { Router } from '#angular/router';
import { ListService } from 'src/app/shared/list.service';
import { NewList } from 'src/app/shared/new-list.model';
import { faWindowClose } from '#fortawesome/free-solid-svg-icons';
import { faPlusCircle } from '#fortawesome/free-solid-svg-icons';
import { faList } from '#fortawesome/free-solid-svg-icons';
import { faSignOutAlt } from '#fortawesome/free-solid-svg-icons';
import { Subject } from 'rxjs';
#Component({
selector: 'app-sub-header',
templateUrl: './sub-header.component.html',
styleUrls: ['./sub-header.component.css']
})
export class SubHeaderComponent implements OnInit {
createdLists: NewList[];
faWindowClose = faWindowClose;
faPlusCircle = faPlusCircle;
faList = faList;
faSignOutAlt = faSignOutAlt;
#Output() closeSub = new Subject();
constructor(private listService: ListService,
private router: Router) { }
ngOnInit(): void {
this.listService.getLists().subscribe((responseData) => {
this.createdLists = responseData;
});
}
onCloseSelect() {
this.closeSub.next();
}
onNewListSelect() {
this.onCloseSelect();
this.router.navigate(['new-list-menu']);
}
onLogOutSelect() {
}
}```

You can accomplish this in many ways, as these components are not related to each other, you can introduce a state service and use observables. see below possible solution
Create a new state service ListStateService
export class ListStateService {
private listData = new BehaviorSubject<NewList >({} as NewList);
listData$ = this.listData .asObservable();
}
Inject ListStateService into NewListMenuComponent
In the onSubmit, after you update,
const lists = this.listService.updateLists(newListObj);
this.listData .next(lists );
Inject ListStateService into SubHeaderComponent
In the ngOnInit(), subscribe to the ListStateService.listData$ and here you will get the value on changes

In your service, use an event emitter (very useful):
import { EventEmitter } from "#angular/core";
#Output() myEvent: EventEmitter<any> = new EventEmitter();
then emit new data to your sub header component through your service like so:
emitEvent (newData: Array<string>) {
this.myEvent.emit({
data: newData,
});
}
Subscribe to new data in your sub header component ngOnInit and use it:
this.myService.myEvent.subscribe((newData: Array<string>) => {
console.log(JSON.stringify(newData.data));
});
Note: Subscriptions will cause memory leaks if constantly re-subscribed in the component, so you can save the subscription and call unsubscribe() on it in the ngOnDestroy callback.

It's a little unclear what you are trying to do, but if you are trying to pass data from a parent component to a child component, you can do this either with Input fields or a ViewChild
to use Input fields your parent might looks like this:
<app-sub-header [names]="names"></app-sub-header>
then use an "Input" field in the child. Updating names in the parent should update the same named variable in the child in real time.

Send JSON from one component to another using routing and not display on URL?

I am trying to pass JSON on routing URL here is my
app.route.ts code
{path: 'calculator', component: CalculatorComponent,data : {some_data : null}},
and my code to route the data is
this.router.navigate(['/home/calculator', {some_data:this.loanData}]);
and the calculator.ts have the oninit method code is like this
import {ActivatedRoute} from '#angular/router';
constructor(private route: ActivatedRoute) {}
sub
ngOnInit() {
this.sub = this.route
.data
.subscribe(v => console.log(v));
}
output is like this
{"some_data":null}
the problem is it's not showing the json, I passed from the ts first component

Is there a reason you want to navigate by url why not use the navigate method like this:
in RouteConf: { path: '/path/:data', name: 'Defined_Path_Name', component: PathComponent }
navigate with: this.router.navigate(['Defined_Path_Name', { data: { entity: 'entity' } } ]);
in /path: console.log(this.routeParams.get('data'))
that got me: Object {entity: "entity"}
//in your route file
in RouteConf: {path: 'calculator/:data', component: CalculatorComponent},
//in your component file navigate by like below
navigate with: this.router.navigate(['/calculator', { data: this.loaddata } ]);
//and get data in /calculator path like
this.data = this.route.snapshot.data['data'];
than console.log(this.data);

Can you try using this, this should work, hope so
app.route.ts code
{path: 'calculator', component: CalculatorComponent},
and your code to route
let someData = {
this.loanData
};
this.router.navigate(['/home/calculator/'+someData]);
and the calculator.ts have the oninit method code is like this
import {ActivatedRoute} from '#angular/router';
constructor(private route: ActivatedRoute) {}
sub
ngOnInit() {
this.route.params
.subscribe(data => {
this.sub = data;
console.log(this.sub);
});
}

Cannot access variable outside the subscription

I have an component in angular. I get data from the API and I instantiate a new object to create a map. But I can't access a variable outside the subscribe function. I also can't access my method.
maps.service.ts
This part, get data form api
import { Injectable } from '#angular/core';
import {HttpClient} from '#angular/common/http';
#Injectable()
export class MapsService {
constructor(private http: HttpClient) { }
getMap(params) {
console.log('Service', params);
return this.http.get('/api/posts/' + params.id);
}
}
map.component.ts
Here, where I build the map with google in the future
import { Component, OnInit } from '#angular/core';
import {MapsService} from '../maps.service';
import {ActivatedRoute} from '#angular/router';
import {MapPath} from '../map-path';
#Component({
selector: 'app-maps',
templateUrl: './maps.component.html',
styleUrls: ['./maps.component.css']
})
export class MapsComponent implements OnInit {
results: any;
params: {};
test: any;
constructor(
private mapsService: MapsService,
private route: ActivatedRoute,
) { }
ngOnInit() {
this.route.params.subscribe( params => {
this.params = params;
});
this.mapsService.getMap(this.params).subscribe(
data => {
this.results = data;
this.test = new MapPath(data, 'test');
},
err => {
console.log('Error occured', err);
});
console.log('this.test', this.test.getX());
console.log('this.results', this.results);
}
}
map-path.ts
Here get the different properties from geoJSON
export class MapPath {
test: string;
constructor(path: any, test: string) {
this.test = test;
console.log('Path', path);
console.log('test', test);
}
getX() {
return this.test;
}
}
Thanks.

Your problem is that Observables are async functions, meaning your subscription callback will happen later than the console.log calls following your this.mapsService.getMap call.
This is guaranteed by async nature of Observables.
You can either move your console logs inside of the subscribe function or create another subscription.
Hope this helps.

Angular 2 Interface throwing error of non existing property

I have an Angular 2 interface books.ts
export interface Books {
artists: Object;
tracks: Object;
}
This is the my service file where I am using it with http request searchService.ts
import { Injectable } from '#angular/core';
import { Http, Response, Headers, RequestOptions } from '#angular/http';
import { Observable } from 'rxjs/Observable';
import { Books } from 'app/pages/search-results/books';
import 'rxjs/add/operator/map'
#Injectable()
export class SearchService {
constructor(private _http:Http) { }
getBook(keyword): Observable<Books[]>{
return this._http.get('https://api.spotify.com/v1/search?q=' + keyword + '&type=track,artist')
.map((response: Response) => <Books[]> response.json());
}
}
And this is my component where I am using interface searchResults.ts
import { Component, OnInit } from '#angular/core';
import { ActivatedRoute, Router } from '#angular/router';
import { SearchService } from 'app/shared/search/search.service';
import { Books } from 'app/pages/search-results/books';
#Component({
selector: 'app-search-results',
templateUrl: './search-results.component.html',
styleUrls: ['./search-results.component.css'],
providers: [SearchService]
})
export class SearchResultsComponent implements OnInit {
keyword: any;
sub: any;
books: Books[];
errMessage: string;
arists: Object;
constructor(private _route: ActivatedRoute, private _router: Router, private _search: SearchService) { }
ngOnInit() {
this.sub = this._route
.queryParams
.subscribe(params => {
// Defaults to 0 if no query param provided.
this.keyword = params['keyword'] || 0;
this.getBooks(this.keyword);
});
//
}
getBooks(value) {
this._search.getBook(value)
.subscribe(
res => {
this.books = res;
console.log(res.artists);
},
error => { this.errMessage = <any>error }
);
}
}
The error comes when I try to console the res.artists. The error says Property 'artists' does not exist on type 'Books[]'. I am new to Angular 2 and doesn't know how to fix that.
The response is looks like
{artists:{limit: 20, item:[]}, tracks:{limit: 20, item:[]}}

I'm not sure but I think you try to get res.artist from collection of books. You can check it by for or e.g res[0].artist to get concrete artist.

getBook function in class SearchService return an array of Books object (Books[])
so, the res in getBooks function in SearchResultsComponent will be an Array of Books.
You can console.log(res) to see detail, if you want access to artists please try with res[0].artists if the res is not an empty array

The problem is that I am getting Object in response and I am assigning it to an Array which is causing the error. I have simply changes the both types to object and it solved my problem.
From this
books: Books[];
To this
books: Books;