Angular 6 - run method in service every 10 seconds

Try with timer from RxJS :

import { Component, OnInit, OnDestroy } from '@angular/core';
import { Subscription, timer } from 'rxjs';
import { switchMap } from 'rxjs/operators';

import { MyService } from 'path/to/the/service/my-service.service';

@Component({
  ......
})
export class MyExampleComponent implements OnInit, OnDestroy {
    subscription: Subscription;
    statusText: string;
    
    constructor(private myService: MyService) {}

    ngOnInit() {
        this.subscription = timer(0, 10000).pipe(
          switchMap(() => this.myService.checkdata())
        ).subscribe(result => this.statusText = result);
    }

    ngOnDestroy() {
        this.subscription.unsubscribe();
    }
}

interval(10000) from RxJS is not appropriate, because it will start to emit values ONLY after 10sec and not immediatly for the first time (and I think that's not what you're looking for).

However, timer(0, 10000), will emit values immediatly (0) and every 10sec (10000) until unsubscription.

Use rxjs timer to call the api request at startup and then every 10s.

This is best achieved by using rxjs to divide and conquer.

Firstly, import the following:

import { timer, Observable, Subject } from 'rxjs';
import { switchMap, takeUntil, catchError } from 'rxjs/operators';

Then add the property to handle request to the api:

private fetchData$: Observable<string> = this.myservice.checkdata();

Next, add the property to handle the timing:

private refreshInterval$: Observable<string> = timer(0, 1000)
.pipe(
  // This kills the request if the user closes the component 
  takeUntil(this.killTrigger),
  // switchMap cancels the last request, if no response have been received since last tick
  switchMap(() => this.fetchData$),
  // catchError handles http throws 
  catchError(error => of('Error'))
);

At last, fire the kill command if the component is killed:

ngOnDestroy(){
  this.killTrigger.next();
}

Here is a StackBlitz Demo.

The rxjs way to do this would be the following.

import { interval } from 'rxjs/observable/interval';
import { map } from 'rxjs/operators';

const timeInterval$ = interval(10000);

timeInterval$.pipe(
  map( () => this.http.get(//some url);
);

In your checkData method you could do something like this:

import { timer, of } from 'rxjs';
import { switchMap, catchError } from 'rxjs/operators';

checkData() {
    return timer(0, 10000)
        .pipe(
           switchMap(_ => this.http.get('my url')),
           catchError(error => of(`Bad request: ${error}`))
        );
}

Then your subscribe will get the result of the http call every 10 seconds.