evt/src/lib/Evt.loosenType.ts

Type safe replacement for node's EventEmitter

import type { SwapEvtType, UnpackEvt, NonPostableEvtLike} from "./types";

/**
 * https://docs.evt.land/api/evt/loosentype
 */
export function loosenType<E extends NonPostableEvtLike<any>, SupersetOfT>(
    evt: E
): UnpackEvt<E> extends SupersetOfT ?
    SwapEvtType<typeof evt, SupersetOfT> : "NOT A SUPERSET" {
    return evt as any;
}

/*
import { Evt } from "./Evt";
const x: Evt<boolean> = loosenType(new Evt<true>()); x;
const y: Evt<boolean> = loosenType(new Evt<number>()); y;
*/