Angular 6 ng lint combineLatest is deprecated

For trailing comma error, remove the comma after (auth, url) => ({auth, url})

const a$ = combineLatest(
  this.aStore.select(b.getAuth),
  this.cStore.select(b.getUrl),
  (auth, url) => ({auth, url}),  // Remove this comma.
);

For missing import error, Make sure you have imports for all the external var's or classes you are using in the file.

Example, in this case, if you havent imported combineLatest, then import it

import { combineLatest } from 'rxjs'; // For RxJS 6.x

import { combineLatest } from 'rxjs/operators'; // For RxJS 5.x

combineLatest is deprecated: resultSelector no longer supported, pipe to map instead

The above warning is recommending to remove the resultSelector the last function you provided in combineLatest observable and provide it as part of map operator as follows

const a$ = combineLatest(
  this.aStore.select(b.getAuth),
  this.cStore.select(b.getUrl)
);

const result$ = a$.pipe(
  map(results => ({auth: results[0], url: results[1]}))
)

UPDATE:

If you see combineLatest is deprecated: Pass arguments in a single array instead then just add []:

const a$ = combineLatest([
  this.aStore.select(b.getAuth),
  this.cStore.select(b.getUrl)
]);
    
const result$ = a$.pipe(
  map(results => ({auth: results[0], url: results[1]}))
)

Unlike the deprecated versions, combineLatest accepts an Array of Observable and returns an array containing the latest values from each. Every stream has to yield in order for combineLatest to yield.

fruitType$ = combineLatest([this.entity$, this.datasetStateService.get$('Fruits')])
  .pipe(map(data => {
    const entity = data[0];
    const dataset = data[1];
    return {
       isApple: (dataset.find(ds => ds.label === 'Apple') as DataItem).id === entity.fruitId,
       isOrange: (dataset.find(ds => ds.label === 'Orange') as DataItem).id === entity.fruitId
    }
}));

Unfortunately you might also get that tslint error if you import combineLatest from operators:

import { combineLatest } from 'rxjs/operators';
    
combineLatest(...array);

instead of,

import { combineLatest } from 'rxjs';
    
combineLatest(...array);