@virtualstate/app-history/src/event-target/respond-event.ts

Native JavaScript [app-history](https://github.com/WICG/app-history) implementation

import {Event, isEvent} from "./event";

export interface RespondEvent<Name extends string | symbol = string, T = unknown> extends Event<Name> {
    /**
     * @param value
     * @throws InvalidStateError
     */
    respondWith(value: T | Promise<T>): void
}

export function isRespondEvent<T = unknown>(value: object): value is RespondEvent<string, T> {
    function isRespondEventLike(value: object): value is Partial<Record<keyof RespondEvent, unknown>> {
        return isEvent(value)
    }
    return (
        isRespondEventLike(value) &&
        typeof value.respondWith === "function"
    )
}