/**
 * @license Use of this source code is governed by an MIT-style license that
 * can be found in the LICENSE file at https://github.com/cartant/rxjs-etc
 */

import { Observable, of } from "rxjs";
import { map } from "rxjs/operators";
import { isObservable } from "../util";
import { combineLatestArray } from "./combineLatestArray";

export function combineLatestObject<T>(
  instance: { [K in keyof T]: T[K] | Observable<T[K]> }
): Observable<T> {
  type K = keyof T;
  const entries = Object.entries(instance) as [K, T[K] | Observable<T[K]>][];
  const observables = entries.map(([, value]) =>
    isObservable(value) ? value : of(value)
  );
  return combineLatestArray(observables).pipe(
    map((values) =>
      values.reduce((acc, value, index) => {
        acc[entries[index][0]] = value;
        return acc;
      }, {} as T)
    )
  );
}