/**
 * The Event interface represents any event which takes place in the DOM; some are user-generated (such as mouse or keyboard events), while others are generated by APIs (such as
 * events that indicate an animation has finished running, a video has been paused, and so forth). While events are usually triggered by such "external" sources, they can also be
 * triggered programmatically, such as by calling the HTMLElement.click() method of an element, or by defining the event, then sending it to a specified target using
 * EventTarget.dispatchEvent(). There are many types of events, some of which use other interfaces based on the main Event interface. Event itself contains the properties and
 * methods which are common to all events.
 */
interface Event {
    /**
     * Returns true or false depending on how event was initialized. True if event goes through its target's ancestors in reverse tree order, and false otherwise.
     */
    readonly bubbles: boolean;
    cancelBubble: boolean;
    readonly cancelable: boolean;
    /**
     * Returns true or false depending on how event was initialized. True if event invokes listeners past a ShadowRoot node that is the root of its target, and false otherwise.
     */
    readonly composed: boolean;
    readonly defaultPrevented: boolean;
    readonly eventPhase: number;
    /**
     * Returns true if event was dispatched by the user agent, and
     * false otherwise.
     */
    readonly isTrusted: boolean;
    returnValue: boolean;
    /**
     * Returns the event's timestamp as the number of milliseconds measured relative to
     * the time origin.
     */
    readonly timeStamp: number;
    /**
     * Unauthorized and redirect error status codes (for example 401, 403, 301, 307)
     */
    readonly status?: number | undefined;
    /**
     * Returns the type of event, e.g.
     * "click", "hashchange", or
     * "submit".
     */
    readonly type: string;
    readonly AT_TARGET: 2;
    readonly BUBBLING_PHASE: 3;
    readonly CAPTURING_PHASE: 1;
    readonly NONE: 0;
    composedPath(): any[];
    initEvent(type: string, bubbles?: boolean, cancelable?: boolean): void;
    preventDefault(): void;
    /**
     * Invoking this method prevents event from reaching
     * any registered event listeners after the current one finishes running and, when dispatched in a tree, also prevents event from reaching any
     * other objects.
     */
    stopImmediatePropagation(): void;
    /**
     * When dispatched in a tree, invoking this method prevents event from reaching any objects other than the current object.
     */
    stopPropagation(): void;
}

interface EventInit {
    bubbles?: boolean | undefined;
    cancelable?: boolean | undefined;
    composed?: boolean | undefined;
}

interface MessageEventInit<T = any> extends EventInit {
    data?: T | undefined;
    lastEventId?: string | undefined;
    origin?: string | undefined;
}

/** The MessageEvent interface represents a message received by a target object. */
interface MessageEvent<T = any> extends Event {
    /**
     * Returns the data of the message.
     */
    readonly data: T;
    /**
     * Returns the last event ID string, for server-sent events.
     */
    readonly lastEventId: string;
    /**
     * Returns the origin of the message, for server-sent events and
     * cross-document messaging.
     */
    readonly origin: string;
}
declare var MessageEvent: {
    prototype: MessageEvent;
    new<T>(type: string, eventInitDict?: MessageEventInit<T>): MessageEvent<T>;
};