@types/node/domain.d.ts

/**
 * **This module is pending deprecation**. Once a replacement API has been
 * finalized, this module will be fully deprecated. Most developers should**not** have cause to use this module. Users who absolutely must have
 * the functionality that domains provide may rely on it for the time being
 * but should expect to have to migrate to a different solution
 * in the future.
 *
 * Domains provide a way to handle multiple different IO operations as a
 * single group. If any of the event emitters or callbacks registered to a
 * domain emit an `'error'` event, or throw an error, then the domain object
 * will be notified, rather than losing the context of the error in the`process.on('uncaughtException')` handler, or causing the program to
 * exit immediately with an error code.
 * @deprecated Since v1.4.2 - Deprecated
 * @see [source](https://github.com/nodejs/node/blob/v16.4.2/lib/domain.js)
 */
declare module 'domain' {
    import EventEmitter = require('node:events');
    /**
     * The `Domain` class encapsulates the functionality of routing errors and
     * uncaught exceptions to the active `Domain` object.
     *
     * To handle the errors that it catches, listen to its `'error'` event.
     */
    class Domain extends EventEmitter {
        /**
         * An array of timers and event emitters that have been explicitly added
         * to the domain.
         */
        members: Array<EventEmitter | NodeJS.Timer>;
        /**
         * The `enter()` method is plumbing used by the `run()`, `bind()`, and`intercept()` methods to set the active domain. It sets `domain.active` and`process.domain` to the domain, and implicitly
         * pushes the domain onto the domain
         * stack managed by the domain module (see {@link exit} for details on the
         * domain stack). The call to `enter()` delimits the beginning of a chain of
         * asynchronous calls and I/O operations bound to a domain.
         *
         * Calling `enter()` changes only the active domain, and does not alter the domain
         * itself. `enter()` and `exit()` can be called an arbitrary number of times on a
         * single domain.
         */
        enter(): void;
        /**
         * The `exit()` method exits the current domain, popping it off the domain stack.
         * Any time execution is going to switch to the context of a different chain of
         * asynchronous calls, it's important to ensure that the current domain is exited.
         * The call to `exit()` delimits either the end of or an interruption to the chain
         * of asynchronous calls and I/O operations bound to a domain.
         *
         * If there are multiple, nested domains bound to the current execution context,`exit()` will exit any domains nested within this domain.
         *
         * Calling `exit()` changes only the active domain, and does not alter the domain
         * itself. `enter()` and `exit()` can be called an arbitrary number of times on a
         * single domain.
         */
        exit(): void;
        /**
         * Run the supplied function in the context of the domain, implicitly
         * binding all event emitters, timers, and lowlevel requests that are
         * created in that context. Optionally, arguments can be passed to
         * the function.
         *
         * This is the most basic way to use a domain.
         *
         * ```js
         * const domain = require('domain');
         * const fs = require('fs');
         * const d = domain.create();
         * d.on('error', (er) => {
         *   console.error('Caught error!', er);
         * });
         * d.run(() => {
         *   process.nextTick(() => {
         *     setTimeout(() => { // Simulating some various async stuff
         *       fs.open('non-existent file', 'r', (er, fd) => {
         *         if (er) throw er;
         *         // proceed...
         *       });
         *     }, 100);
         *   });
         * });
         * ```
         *
         * In this example, the `d.on('error')` handler will be triggered, rather
         * than crashing the program.
         */
        run<T>(fn: (...args: any[]) => T, ...args: any[]): T;
        /**
         * Explicitly adds an emitter to the domain. If any event handlers called by
         * the emitter throw an error, or if the emitter emits an `'error'` event, it
         * will be routed to the domain's `'error'` event, just like with implicit
         * binding.
         *
         * This also works with timers that are returned from `setInterval()` and `setTimeout()`. If their callback function throws, it will be caught by
         * the domain `'error'` handler.
         *
         * If the Timer or `EventEmitter` was already bound to a domain, it is removed
         * from that one, and bound to this one instead.
         * @param emitter emitter or timer to be added to the domain
         */
        add(emitter: EventEmitter | NodeJS.Timer): void;
        /**
         * The opposite of {@link add}. Removes domain handling from the
         * specified emitter.
         * @param emitter emitter or timer to be removed from the domain
         */
        remove(emitter: EventEmitter | NodeJS.Timer): void;
        /**
         * The returned function will be a wrapper around the supplied callback
         * function. When the returned function is called, any errors that are
         * thrown will be routed to the domain's `'error'` event.
         *
         * ```js
         * const d = domain.create();
         *
         * function readSomeFile(filename, cb) {
         *   fs.readFile(filename, 'utf8', d.bind((er, data) => {
         *     // If this throws, it will also be passed to the domain.
         *     return cb(er, data ? JSON.parse(data) : null);
         *   }));
         * }
         *
         * d.on('error', (er) => {
         *   // An error occurred somewhere. If we throw it now, it will crash the program
         *   // with the normal line number and stack message.
         * });
         * ```
         * @param callback The callback function
         * @return The bound function
         */
        bind<T extends Function>(callback: T): T;
        /**
         * This method is almost identical to {@link bind}. However, in
         * addition to catching thrown errors, it will also intercept `Error` objects sent as the first argument to the function.
         *
         * In this way, the common `if (err) return callback(err);` pattern can be replaced
         * with a single error handler in a single place.
         *
         * ```js
         * const d = domain.create();
         *
         * function readSomeFile(filename, cb) {
         *   fs.readFile(filename, 'utf8', d.intercept((data) => {
         *     // Note, the first argument is never passed to the
         *     // callback since it is assumed to be the 'Error' argument
         *     // and thus intercepted by the domain.
         *
         *     // If this throws, it will also be passed to the domain
         *     // so the error-handling logic can be moved to the 'error'
         *     // event on the domain instead of being repeated throughout
         *     // the program.
         *     return cb(null, JSON.parse(data));
         *   }));
         * }
         *
         * d.on('error', (er) => {
         *   // An error occurred somewhere. If we throw it now, it will crash the program
         *   // with the normal line number and stack message.
         * });
         * ```
         * @param callback The callback function
         * @return The intercepted function
         */
        intercept<T extends Function>(callback: T): T;
    }
    function create(): Domain;
}
declare module 'node:domain' {
    export * from 'domain';
}