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

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

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

export function createEvent<T extends string | symbol, E extends Event<T>>(event: E): E {
    if (typeof CustomEvent !== "undefined" && typeof event.type === "string") {
        if (event instanceof CustomEvent) {
            return event;
        }
        const { type, detail, ...rest } = event;
        const customEvent: unknown = new CustomEvent(type, {
            detail: detail ?? rest
        });
        Object.assign(customEvent, rest);
        assertEvent<T, E>(customEvent, event.type);
        return customEvent;
    }
    return event;
}