evt/src/lib/types/helper/UnpackEvt.ts

Type safe replacement for node's EventEmitter

import type { NonPostableEvtLike } from "../interfaces/NonPostableEvtLike";

type UnpackEvtBase<T extends NonPostableEvtLike<any>> = T extends NonPostableEvtLike<infer U> ? U : never;

type UnpackEvtRecord<T extends { [key: string]: any; }> = {
    [P in keyof T]: T[P] extends NonPostableEvtLike<any> ? UnpackEvtBase<T[P]> : T[P];
};

type UnpackNonNullableEvt<T extends ({ [key: string]: any; } | NonPostableEvtLike<any>)> =
    T extends NonPostableEvtLike<any> ? UnpackEvtBase<T> :
    UnpackEvtRecord<T>
    ;

/** https://docs.evt.land/api/helpertypes#unpackevt-less-than-e-greater-than */
export type UnpackEvt<T extends ({ [key: string]: any; } | NonPostableEvtLike<any> | undefined | null)> =
    UnpackNonNullableEvt<NonNullable<T>>