@graphql-markdown/core/dist/event-emitter.d.ts

GraphQL-Markdown core package for generating Markdown documentation from a GraphQL schema.

import { EventEmitter } from "node:events";
import type { ICancellableEvent } from "@graphql-markdown/types";
/**
 * Result object returned when emitting a cancellable event.
 *
 * @category Events
 */
export interface EmitResult {
    /**
     * Array of errors that occurred during handler execution.
     * Handlers continue executing even if previous handlers throw errors.
     */
    errors: Error[];
    /**
     * Whether any handler called preventDefault() on the event.
     * Only applicable if the event is cancellable.
     */
    defaultPrevented: boolean;
}
/**
 * Custom EventEmitter that supports cancellable events with sequential handler execution.
 *
 * Features:
 * - Executes async handlers sequentially (one after another)
 * - Collects errors without stopping handler execution
 * - Supports stopPropagation to halt handler chain
 * - Returns execution results to emitters
 *
 * @category Events
 */
declare class CancellableEventEmitter extends EventEmitter {
    private static toError;
    private static isDefaultPrevented;
    /**
     * Emit an event asynchronously with cancellable event support.
     *
     * Handlers are executed sequentially in registration order.
     * If a handler throws an error, it's collected but execution continues.
     * If event.propagationStopped becomes true, remaining handlers are skipped.
     *
     * After all handlers execute, if the event has a defaultAction function and
     * preventDefault() was not called, the default action is automatically executed.
     *
     * @param eventName - Name of the event to emit
     * @param event - Cancellable event object with preventDefault() and stopPropagation() methods
     * @returns Promise resolving to EmitResult with errors and cancellation status
     *
     * @example
     * ```typescript
     * const events = getEvents();
     * const event = new SchemaLoadEvent({
     *   schemaLocation: '/path/to/schema',
     *   defaultAction: async () => {
     *     // This runs automatically if not prevented
     *     await loadSchema('/path/to/schema');
     *   }
     * });
     *
     * const { errors, defaultPrevented } = await events.emitAsync('beforeLoadSchema', event);
     *
     * if (errors.length > 0) {
     *   console.error('Errors occurred:', errors);
     * }
     * ```
     */
    emitAsync(eventName: string, event: ICancellableEvent): Promise<EmitResult>;
    private invokeListener;
    private emitToListeners;
    private runDefaultAction;
}
/**
 * Get the singleton event emitter instance.
 *
 * Creates the instance on first call, then returns the same instance on subsequent calls.
 * This ensures all parts of the application share the same event bus.
 *
 * @returns The singleton CancellableEventEmitter instance
 *
 * @example
 * ```typescript
 * // In generator.ts
 * const events = getEvents();
 * events.on('beforeLoadSchema', handler);
 *
 * // In renderer.ts - same instance!
 * const events = getEvents();
 * await events.emitAsync('beforeLoadSchema', event);
 * ```
 *
 * @category Events
 */
export declare const getEvents: () => CancellableEventEmitter;
/**
 * Reset the event emitter singleton.
 *
 * Removes all event listeners and clears the instance.
 * The next call to getEvents() will create a fresh instance.
 *
 * **Important:** This should only be used in tests to ensure test isolation.
 *
 * @example
 * ```typescript
 * // In test setup
 * afterEach(() => {
 *   resetEvents();
 *   jest.restoreAllMocks();
 * });
 * ```
 *
 * @category Events
 */
export declare const resetEvents: () => void;
export {};
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