kitten.sh
1import type { Sink, Source } from 'wonka';
2import { subscribe, take, filter, toPromise, pipe } from 'wonka';
3import type { OperationResult, OperationResultSource } from '../types';
4
5/** Patches a `toPromise` method onto the `Source` passed to it.
6 * @param source$ - the Wonka {@link Source} to patch.
7 * @returns The passed `source$` with a patched `toPromise` method as a {@link PromisifiedSource}.
8 * @internal
9 */
10export function withPromise<T extends OperationResult>(
11 _source$: Source<T>
12): OperationResultSource<T> {
13 const source$ = ((sink: Sink<T>) =>
14 _source$(sink)) as OperationResultSource<T>;
15 source$.toPromise = () =>
16 pipe(
17 source$,
18 filter(result => !result.stale && !result.hasNext),
19 take(1),
20 toPromise
21 );
22 source$.then = (onResolve, onReject) =>
23 source$.toPromise().then(onResolve, onReject);
24 source$.subscribe = onResult => subscribe(onResult)(source$);
25 return source$;
26}