postmark/dist/client/models/client/Callback.d.ts

Official Node.js client library for the Postmark HTTP API - https://www.postmarkapp.com

import * as Errors from "../../errors/Errors";
/**
 * A standard node callback. All errors returned to this callback will be a in namespace 'PostmarkError'
 */
export type Callback<T> = (error: (Errors.PostmarkError | null), result: (T | null)) => void;