/// <reference types="node" />
/**
 * Snapshots various global values and allows rolling back to the snapshot.
 *
 * In particular, it:
 * - Restores `require.cache`, typically useful for allowing modules to be
 *   loaded again fresh.
 * - Restores `require.extensions`, typically useful for unloading loader hooks
 *   such as babel-register or ts-node.
 * - Restores event listeners on `process`, typically useful for preventing
 *   hooks (especially 'exit') from being called on un-cached modules.
 */
export default class ProcessSnapshot {
    private readonly requireImpl;
    private readonly processImpl;
    private readonly log;
    private readonly cacheEntries;
    private readonly extensions;
    private readonly processEvents;
    constructor(requireImpl?: typeof require, processImpl?: typeof process, log?: typeof console.log);
    /**
     * Restores the snapshot that was captured on construction.
     */
    restore(): void;
    /**
     * Helper to diff two maps used as snapshots.
     */
    private static diffMaps;
    /**
     * Restores `require.cache` in place.
     */
    private restoreRequireCache;
    /**
     * Restores `require.extensions` in place.
     */
    private restoreExtensions;
    /**
     * Restores `process` events using the `EventEmitter` API.
     */
    private restoreProcessEvents;
    /**
     * Snapshots the current state of `require.cache`.
     */
    private snapshotRequireCache;
    /**
     * Snapshots the current state of `require.extensions`.
     */
    private snapshotRequireExtensions;
    /**
     * Snapshots the current state of `process` events.
     */
    private snapshotProcessEvents;
}