import { fromEventPattern, NEVER } from "rxjs";
import { map, startWith, takeUntil } from "rxjs/operators";

type MediaQueryList = any;
type Query = any;

class MyClass {
  private _destroy = NEVER;
  private _registerQuery(query: string): Query {
    const mql: MediaQueryList = null;
    const queryObservable = fromEventPattern<MediaQueryList>(
      (listener: Function) => {},
      (listener: Function) => {}
    ).pipe(
      takeUntil(this._destroy),
      ~~~~~~~~~                                                 [no-unsafe-takeuntil]
      startWith(mql),
      map((nextMql: MediaQueryList) => ({}))
    );
    const output = { observable: queryObservable, mql: mql };
    return output;
  }
}

[no-unsafe-takeuntil]: Applying operators after takeUntil is forbidden