declare const __context__: unique symbol;
/** Event fired by a context requester to signal it desires a named context. */
declare class ContextRequestEvent<T = unknown> extends Event {
    /** Context key associated with the Event. */
    readonly context: ExtractContext<T>;
    /** Callback whose provider with a matching context should invoke. */
    readonly callback: ContextCallback<ContextType<T>>;
    /** Indicates whether the context should be provided more than once. */
    readonly subscribe?: boolean | undefined;
    constructor(
    /** Context key associated with the Event. */
    context: ExtractContext<T>, 
    /** Callback whose provider with a matching context should invoke. */
    callback: ContextCallback<ContextType<T>>, 
    /** Indicates whether the context should be provided more than once. */
    subscribe?: boolean | undefined);
}
/** Returns a context of the given key and value type. */
declare const createContext: <ValueType>(key: unknown) => Context<typeof key, ValueType>;
/** Branded context. */
type Context<KeyType = unknown, ValueType = unknown> = KeyType & {
    [__context__]: ValueType;
};
/** Data by branded context. */
type ContextType<T> = T extends Context<infer _KeyType, infer ValueType> ? ValueType : unknown;
/** Callback function by branded contenxt. */
type ContextCallback<ValueType> = (value: ValueType, unsubscribe?: () => void) => void;
/** Extracts a branded context or unknown. */
type ExtractContext<T> = T extends Context ? T : unknown;
declare global {
    interface WindowEventMap {
        /** Event emitted by any target which desires a context value to be injected by an external provider. */
        "context-request": ContextRequestEvent;
    }
    interface ElementEventMap {
        /** Event emitted by any target which desires a context value to be injected by an external provider. */
        "context-request": ContextRequestEvent;
    }
    interface HTMLElementEventMap {
        /** Event emitted by any target which desires a context value to be injected by an external provider. */
        "context-request": ContextRequestEvent;
    }
}
interface EventTargetConstructor<T = EventTarget> {
    new (...args: any[]): EventTarget & T;
    prototype: EventTarget & T;
}
export { type Context, type ContextCallback, type ContextType, type EventTargetConstructor, type ExtractContext, ContextRequestEvent, createContext };