bc-webclient-mcp/dist/core/abort.js

Model Context Protocol (MCP) server for Microsoft Dynamics 365 Business Central via WebUI protocol. Enables AI assistants to interact with BC through the web client protocol, supporting Card, List, and Document pages with full line item support and server

/**
 * AbortSignal Utilities
 *
 * Utilities for composing AbortSignals with timeouts and distinguishing
 * external abort from deadline exceeded.
 *
 * Uses Node 20+ native AbortSignal.timeout() and AbortSignal.any() for
 * efficient signal composition.
 */
/**
 * Composes an optional parent AbortSignal with a timeout deadline.
 *
 * Uses Node 20+ native AbortSignal.timeout() and AbortSignal.any() for
 * efficient composition. The returned signal aborts when either:
 * - The parent signal aborts (external cancellation)
 * - The timeout expires (deadline exceeded)
 *
 * @param parent - Optional parent AbortSignal (e.g., from upstream caller)
 * @param timeoutMs - Timeout in milliseconds
 * @returns Composed AbortSignal that aborts on parent abort OR timeout
 *
 * @example
 * ```ts
 * // Timeout only
 * const signal = composeWithTimeout(undefined, 5000);
 *
 * // Compose with parent
 * const userSignal = new AbortController().signal;
 * const signal = composeWithTimeout(userSignal, 5000);
 * // Aborts if userSignal aborts OR after 5 seconds
 * ```
 */
export function composeWithTimeout(parent, timeoutMs) {
    const deadline = AbortSignal.timeout(timeoutMs);
    // If no parent, just return the timeout signal
    if (!parent) {
        return deadline;
    }
    // Compose parent with deadline using native AbortSignal.any()
    // Aborts when either signal aborts
    return AbortSignal.any([parent, deadline]);
}
export function isTimeoutAbortReason(reason) {
    // Node 20+ timeout creates DOMException with name === 'TimeoutError'
    return (typeof reason === 'object' &&
        reason !== null &&
        reason.name === 'TimeoutError');
}
/**
 * Checks if an error is a DOMException with name 'AbortError'.
 *
 * This is thrown by native AbortSignal-aware APIs when aborted.
 *
 * @param e - The error to check
 * @returns true if the error is an abort error
 *
 * @example
 * ```ts
 * try {
 *   await fetch(url, { signal });
 * } catch (e) {
 *   if (isAbortError(e)) {
 *     // Request was aborted
 *   }
 * }
 * ```
 */
export function isAbortError(e) {
    return (typeof e === 'object' &&
        e !== null &&
        e.name === 'AbortError');
}
/**
 * Determines if a signal was aborted externally (not by timeout).
 *
 * Useful for distinguishing user cancellation from deadline expiration.
 *
 * @param signal - The AbortSignal to check
 * @returns true if aborted by external cancel (not timeout)
 *
 * @example
 * ```ts
 * if (signal.aborted) {
 *   if (wasExternallyAborted(signal)) {
 *     return new AbortedError('Operation cancelled');
 *   } else {
 *     return new TimeoutError('Operation timed out');
 *   }
 * }
 * ```
 */
export function wasExternallyAborted(signal) {
    if (!signal || !signal.aborted) {
        return false;
    }
    // If the reason is a timeout, it's NOT an external abort
    if (isTimeoutAbortReason(signal.reason)) {
        return false;
    }
    // Any other abort reason is considered external
    return true;
}
/**
 * Creates an abort listener that removes itself after firing once.
 *
 * Convenience helper for the common pattern of listening for abort
 * and cleaning up the listener.
 *
 * @param signal - The AbortSignal to listen to
 * @param callback - Function to call when aborted
 * @returns Function to manually remove the listener (if not yet aborted)
 *
 * @example
 * ```ts
 * const cleanup = onceAborted(signal, () => {
 *   // Handle abort
 *   ws.close();
 * });
 *
 * // Later, if you want to remove listener before abort:
 * cleanup();
 * ```
 */
export function onceAborted(signal, callback) {
    const listener = () => callback();
    signal.addEventListener('abort', listener, { once: true });
    // Return cleanup function
    return () => {
        signal.removeEventListener('abort', listener);
    };
}
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