Icon LinkClass: WalletManager

@fuel-ts/account .WalletManager

WalletManager is a upper package to manage multiple vaults like mnemonic and privateKeys.

• VaultTypes can be add to WalletManager.Vaults enabling to add custom Vault types.
• Storage can be instantiate when initializing enabling custom storage types.

Icon LinkHierarchy

• EventEmitter

  ↳ WalletManager

Icon LinkConstructors

Icon Linkconstructor

• new WalletManager(options?): WalletManager

Icon LinkParameters

Icon LinkReturns

WalletManager

Icon LinkOverrides

EventEmitter.constructor

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:71 Icon Link

Icon LinkProperties

Icon Link#isLocked

• Private #isLocked: boolean = true

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:69 Icon Link

Icon Link#passphrase

• Private #passphrase: string = ''

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:68 Icon Link

Icon Link#vaults

• Private #vaults: VaultsState = []

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:67 Icon Link

Icon LinkSTORAGE_KEY

• Readonly STORAGE_KEY: string = 'WalletManager'

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:64 Icon Link

Icon Linkstorage

• Readonly storage: StorageAbstract

Storage

Persistent encrypted data. The default storage works only on memory.

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:62 Icon Link

Icon LinkVaults

▪ Static Vaults: (typeof MnemonicVault | typeof PrivateKeyVault )[]

Vaults

Vaults are responsible to store secret keys and return an Wallet instance, to interact with the network.

Each vault has access to its own state

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:56 Icon Link

Icon LinkcaptureRejectionSymbol

▪ Static Readonly captureRejectionSymbol: typeof captureRejectionSymbol

Value: Symbol.for('nodejs.rejection')

See how to write a custom rejection handler.

Since

v13.4.0, v12.16.0

Icon LinkInherited from

EventEmitter.captureRejectionSymbol

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:452

Icon LinkcaptureRejections

▪ Static captureRejections: boolean

Value: boolean Icon Link

Change the default captureRejections option on all new EventEmitter objects.

Since

v13.4.0, v12.16.0

Icon LinkInherited from

EventEmitter.captureRejections

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:459

Icon LinkdefaultMaxListeners

▪ Static defaultMaxListeners: number

By default, a maximum of 10 listeners can be registered for any single event. This limit can be changed for individual EventEmitter instances using the emitter.setMaxListeners(n) method. To change the default for allEventEmitter instances, the events.defaultMaxListeners property can be used. If this value is not a positive number, a RangeError is thrown.

Take caution when setting the events.defaultMaxListeners because the change affects all EventEmitter instances, including those created before the change is made. However, calling emitter.setMaxListeners(n) still has precedence over events.defaultMaxListeners.

This is not a hard limit. The EventEmitter instance will allow more listeners to be added but will output a trace warning to stderr indicating that a "possible EventEmitter memory leak" has been detected. For any single EventEmitter, the emitter.getMaxListeners() and emitter.setMaxListeners() methods can be used to temporarily avoid this warning:

import { EventEmitter } from 'node:events';
const emitter = new EventEmitter();
emitter.setMaxListeners(emitter.getMaxListeners() + 1);
emitter.once('event', () => {
  // do stuff
  emitter.setMaxListeners(Math.max(emitter.getMaxListeners() - 1, 0));
});

The --trace-warnings command-line flag can be used to display the stack trace for such warnings.

The emitted warning can be inspected with process.on('warning') and will have the additional emitter, type, and count properties, referring to the event emitter instance, the event's name and the number of attached listeners, respectively. Its name property is set to 'MaxListenersExceededWarning'.

Since

v0.11.2

Icon LinkInherited from

EventEmitter.defaultMaxListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:498

Icon LinkerrorMonitor

▪ Static Readonly errorMonitor: typeof errorMonitor

This symbol shall be used to install a listener for only monitoring 'error' events. Listeners installed using this symbol are called before the regular 'error' listeners are called.

Installing a listener using this symbol does not change the behavior once an 'error' event is emitted. Therefore, the process will still crash if no regular 'error' listener is installed.

Since

v13.6.0, v12.17.0

Icon LinkInherited from

EventEmitter.errorMonitor

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:445

Icon LinkAccessors

Icon LinkisLocked

• get isLocked(): boolean

Icon LinkReturns

boolean

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:76 Icon Link

Icon LinkMethods

Icon Link#deserializeVaults

▸ #deserializeVaults(vaults): { title: undefined | string ; type: string ; vault: MnemonicVault | PrivateKeyVault }[]

Deserialize all vaults to state

This is only accessible from inside the class

Icon LinkParameters

Icon LinkReturns

{ title: undefined | string ; type: string ; vault: MnemonicVault | PrivateKeyVault }[]

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:287 Icon Link

Icon Link#serializeVaults

▸ #serializeVaults(vaults): { data: { secret?: string } ; title: undefined | string ; type: string }[]

Serialize all vaults to store

This is only accessible from inside the class

Icon LinkParameters

Icon LinkReturns

{ data: { secret?: string } ; title: undefined | string ; type: string }[]

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:274 Icon Link

Icon Link[captureRejectionSymbol]

▸ [captureRejectionSymbol]<K>(error, event, ...args): void

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

void

Icon LinkInherited from

EventEmitter.[captureRejectionSymbol]

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:136

Icon LinkaddAccount

▸ addAccount(options?): Promise<WalletManagerAccount >

Add account to a selected vault or on the first vault as default. If not vaults are adds it will return error

Icon LinkParameters

Icon LinkReturns

Promise<WalletManagerAccount >

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:143 Icon Link

Icon LinkaddListener

▸ addListener<K>(eventName, listener): this

Alias for emitter.on(eventName, listener).

Since

v0.1.26

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.addListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:597

Icon LinkaddVault

▸ addVault(vaultConfig): Promise<void>

Add Vault, the vaultConfig.type will look for the Vaults supported if didn't found it will throw.

Icon LinkParameters

Icon LinkReturns

Promise<void>

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:170 Icon Link

Icon Linkemit

▸ emit<K>(eventName, ...args): boolean

Synchronously calls each of the listeners registered for the event named eventName, in the order they were registered, passing the supplied arguments to each.

Returns true if the event had listeners, false otherwise.

import { EventEmitter } from 'node:events';
const myEmitter = new EventEmitter();
 
// First listener
myEmitter.on('event', function firstListener() {
  console.log('Helloooo! first listener');
});
// Second listener
myEmitter.on('event', function secondListener(arg1, arg2) {
  console.log(`event with parameters ${arg1}, ${arg2} in second listener`);
});
// Third listener
myEmitter.on('event', function thirdListener(...args) {
  const parameters = args.join(', ');
  console.log(`event with parameters ${parameters} in third listener`);
});
 
console.log(myEmitter.listeners('event'));
 
myEmitter.emit('event', 1, 2, 3, 4, 5);
 
// Prints:
// [
//   [Function: firstListener],
//   [Function: secondListener],
//   [Function: thirdListener]
// ]
// Helloooo! first listener
// event with parameters 1, 2 in second listener
// event with parameters 1, 2, 3, 4, 5 in third listener

Since

v0.1.26

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

boolean

Icon LinkInherited from

EventEmitter.emit

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:859

Icon LinkeventNames

▸ eventNames(): (string | symbol)[]

Returns an array listing the events for which the emitter has registered listeners. The values in the array are strings or Symbols.

import { EventEmitter } from 'node:events';
 
const myEE = new EventEmitter();
myEE.on('foo', () => {});
myEE.on('bar', () => {});
 
const sym = Symbol('symbol');
myEE.on(sym, () => {});
 
console.log(myEE.eventNames());
// Prints: [ 'foo', 'bar', Symbol(symbol) ]

Since

v6.0.0

Icon LinkReturns

(string | symbol)[]

Icon LinkInherited from

EventEmitter.eventNames

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:922

Icon LinkexportPrivateKey

▸ exportPrivateKey(address): string

Export specific account privateKey

Icon LinkParameters

Icon LinkReturns

string

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:128 Icon Link

Icon LinkexportVault

▸ exportVault<T>(vaultId): ReturnType<T["serialize"]>

Return the vault serialized object containing all the privateKeys, the format of the return depends on the Vault type.

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

ReturnType<T["serialize"]>

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:84 Icon Link

Icon LinkgetAccounts

▸ getAccounts(): WalletManagerAccount []

List all accounts on the Wallet Manager not vault information is revealed

Icon LinkReturns

WalletManagerAccount []

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:105 Icon Link

Icon LinkgetMaxListeners

▸ getMaxListeners(): number

Returns the current max listener value for the EventEmitter which is either set by emitter.setMaxListeners(n) or defaults to defaultMaxListeners .

Since

v1.0.0

Icon LinkReturns

number

Icon LinkInherited from

EventEmitter.getMaxListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:774

Icon LinkgetVaultClass

▸ getVaultClass(type): typeof MnemonicVault | typeof PrivateKeyVault

Return a instantiable Class reference from WalletManager.Vaults supported list.

Icon LinkParameters

Icon LinkReturns

typeof MnemonicVault | typeof PrivateKeyVault

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:301 Icon Link

Icon LinkgetVaults

▸ getVaults(): { title?: string ; type: string ; vaultId: number }[]

List all vaults on the Wallet Manager, this function not return secret's

Icon LinkReturns

{ title?: string ; type: string ; vaultId: number }[]

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:94 Icon Link

Icon LinkgetWallet

▸ getWallet(address): WalletUnlocked

Create a Wallet instance for the specific account

Icon LinkParameters

Icon LinkReturns

WalletUnlocked

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:115 Icon Link

Icon LinklistenerCount

▸ listenerCount<K>(eventName, listener?): number

Returns the number of listeners listening for the event named eventName. If listener is provided, it will return how many times the listener is found in the list of the listeners of the event.

Since

v3.2.0

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

number

Icon LinkInherited from

EventEmitter.listenerCount

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:868

Icon Linklisteners

▸ listeners<K>(eventName): Function[]

Returns a copy of the array of listeners for the event named eventName.

server.on('connection', (stream) => {
  console.log('someone connected!');
});
console.log(util.inspect(server.listeners('connection')));
// Prints: [ [Function] ]

Since

v0.1.26

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

Function[]

Icon LinkInherited from

EventEmitter.listeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:787

Icon LinkloadState

▸ loadState(): Promise<void>

Retrieve and decrypt WalletManager state from storage

Icon LinkReturns

Promise<void>

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:246 Icon Link

Icon Linklock

▸ lock(): void

Lock wallet. It removes passphrase from class instance, encrypt and hide all address and secrets.

Icon LinkReturns

void

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:191 Icon Link

Icon Linkoff

▸ off<K>(eventName, listener): this

Alias for emitter.removeListener().

Since

v10.0.0

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.off

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:747

Icon Linkon

▸ on<K>(eventName, listener): this

Adds the listener function to the end of the listeners array for the event named eventName. No checks are made to see if the listener has already been added. Multiple calls passing the same combination of eventName and listener will result in the listener being added, and called, multiple times.

server.on('connection', (stream) => {
  console.log('someone connected!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

By default, event listeners are invoked in the order they are added. The emitter.prependListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

import { EventEmitter } from 'node:events';
const myEE = new EventEmitter();
myEE.on('foo', () => console.log('a'));
myEE.prependListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
//   b
//   a

Since

v0.1.101

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.on

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:629

Icon Linkonce

▸ once<K>(eventName, listener): this

Adds a one-time listener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked.

server.once('connection', (stream) => {
  console.log('Ah, we have our first user!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

By default, event listeners are invoked in the order they are added. The emitter.prependOnceListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

import { EventEmitter } from 'node:events';
const myEE = new EventEmitter();
myEE.once('foo', () => console.log('a'));
myEE.prependOnceListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
//   b
//   a

Since

v0.3.0

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.once

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:659

Icon LinkprependListener

▸ prependListener<K>(eventName, listener): this

Adds the listener function to the beginning of the listeners array for the event named eventName. No checks are made to see if the listener has already been added. Multiple calls passing the same combination of eventName and listener will result in the listener being added, and called, multiple times.

server.prependListener('connection', (stream) => {
  console.log('someone connected!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v6.0.0

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.prependListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:886

Icon LinkprependOnceListener

▸ prependOnceListener<K>(eventName, listener): this

Adds a one-timelistener function for the event named eventName to the beginning of the listeners array. The next time eventName is triggered, this listener is removed, and then invoked.

server.prependOnceListener('connection', (stream) => {
  console.log('Ah, we have our first user!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v6.0.0

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.prependOnceListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:902

Icon LinkrawListeners

▸ rawListeners<K>(eventName): Function[]

Returns a copy of the array of listeners for the event named eventName, including any wrappers (such as those created by .once()).

import { EventEmitter } from 'node:events';
const emitter = new EventEmitter();
emitter.once('log', () => console.log('log once'));
 
// Returns a new Array with a function `onceWrapper` which has a property
// `listener` which contains the original listener bound above
const listeners = emitter.rawListeners('log');
const logFnWrapper = listeners[0];
 
// Logs "log once" to the console and does not unbind the `once` event
logFnWrapper.listener();
 
// Logs "log once" to the console and removes the listener
logFnWrapper();
 
emitter.on('log', () => console.log('log persistently'));
// Will return a new Array with a single function bound by `.on()` above
const newListeners = emitter.rawListeners('log');
 
// Logs "log persistently" twice
newListeners[0]();
emitter.emit('log');

Since

v9.4.0

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

Function[]

Icon LinkInherited from

EventEmitter.rawListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:818

Icon LinkremoveAllListeners

▸ removeAllListeners(eventName?): this

Removes all listeners, or those of the specified eventName.

It is bad practice to remove listeners added elsewhere in the code, particularly when the EventEmitter instance was created by some other component or module (e.g. sockets or file streams).

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v0.1.26

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.removeAllListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:758

Icon LinkremoveListener

▸ removeListener<K>(eventName, listener): this

Removes the specified listener from the listener array for the event named eventName.

const callback = (stream) => {
  console.log('someone connected!');
};
server.on('connection', callback);
// ...
server.removeListener('connection', callback);

removeListener() will remove, at most, one instance of a listener from the listener array. If any single listener has been added multiple times to the listener array for the specified eventName, then removeListener() must be called multiple times to remove each instance.

Once an event is emitted, all listeners attached to it at the time of emitting are called in order. This implies that any removeListener() or removeAllListeners() calls after emitting and before the last listener finishes execution will not remove them fromemit() in progress. Subsequent events behave as expected.

import { EventEmitter } from 'node:events';
class MyEmitter extends EventEmitter {}
const myEmitter = new MyEmitter();
 
const callbackA = () => {
  console.log('A');
  myEmitter.removeListener('event', callbackB);
};
 
const callbackB = () => {
  console.log('B');
};
 
myEmitter.on('event', callbackA);
 
myEmitter.on('event', callbackB);
 
// callbackA removes listener callbackB but it will still be called.
// Internal listener array at time of emit [callbackA, callbackB]
myEmitter.emit('event');
// Prints:
//   A
//   B
 
// callbackB is now removed.
// Internal listener array [callbackA]
myEmitter.emit('event');
// Prints:
//   A

Because listeners are managed using an internal array, calling this will change the position indices of any listener registered after the listener being removed. This will not impact the order in which listeners are called, but it means that any copies of the listener array as returned by the emitter.listeners() method will need to be recreated.

When a single function has been added as a handler multiple times for a single event (as in the example below), removeListener() will remove the most recently added instance. In the example the once('ping') listener is removed:

import { EventEmitter } from 'node:events';
const ee = new EventEmitter();
 
function pong() {
  console.log('pong');
}
 
ee.on('ping', pong);
ee.once('ping', pong);
ee.removeListener('ping', pong);
 
ee.emit('ping');
ee.emit('ping');

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v0.1.26

Icon LinkType parameters

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.removeListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:742

Icon LinkremoveVault

▸ removeVault(index): Promise<void>

Remove vault by index, by remove the vault you also remove all accounts created by the vault.

Icon LinkParameters

Icon LinkReturns

Promise<void>

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:161 Icon Link

Icon LinksaveState

▸ saveState(): Promise<void>

Store encrypted WalletManager state on storage

Icon LinkReturns

Promise<void>

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:259 Icon Link

Icon LinksetMaxListeners

▸ setMaxListeners(n): this

By default EventEmitters will print a warning if more than 10 listeners are added for a particular event. This is a useful default that helps finding memory leaks. The emitter.setMaxListeners() method allows the limit to be modified for this specific EventEmitter instance. The value can be set to Infinity (or 0) to indicate an unlimited number of listeners.

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v0.3.5

Icon LinkParameters

Icon LinkReturns

this

Icon LinkInherited from

EventEmitter.setMaxListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:768

Icon Linkunlock

▸ unlock(passphrase): Promise<void>

Unlock wallet. It sets passphrase on WalletManger instance load all address from configured vaults. Vaults with secrets are not unlocked or instantiated on this moment.

Icon LinkParameters

Icon LinkReturns

Promise<void>

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:205 Icon Link

Icon LinkupdatePassphrase

▸ updatePassphrase(oldpass, newpass): Promise<void>

Update WalletManager encryption passphrase

Icon LinkParameters

Icon LinkReturns

Promise<void>

Icon LinkDefined in

packages/account/src/wallet-manager/wallet-manager.ts:227 Icon Link

Icon LinkaddAbortListener

▸ addAbortListener(signal, resource): Disposable

Listens once to the abort event on the provided signal.

Listening to the abort event on abort signals is unsafe and may lead to resource leaks since another third party with the signal can call e.stopImmediatePropagation(). Unfortunately Node.js cannot change this since it would violate the web standard. Additionally, the original API makes it easy to forget to remove listeners.

This API allows safely using AbortSignals in Node.js APIs by solving these two issues by listening to the event such that stopImmediatePropagation does not prevent the listener from running.

Returns a disposable so that it may be unsubscribed from more easily.

import { addAbortListener } from 'node:events';
 
function example(signal) {
  let disposable;
  try {
    signal.addEventListener('abort', (e) => e.stopImmediatePropagation());
    disposable = addAbortListener(signal, (e) => {
      // Do something when signal is aborted.
    });
  } finally {
    disposable?.[Symbol.dispose]();
  }
}

Since

v20.5.0

Icon LinkParameters

Icon LinkReturns

Disposable

Disposable that removes the abort listener.

Icon LinkInherited from

EventEmitter.addAbortListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:437

Icon LinkgetEventListeners

▸ getEventListeners(emitter, name): Function[]

Returns a copy of the array of listeners for the event named eventName.

For EventEmitters this behaves exactly the same as calling .listeners on the emitter.

For EventTargets this is the only way to get the event listeners for the event target. This is useful for debugging and diagnostic purposes.

import { getEventListeners, EventEmitter } from 'node:events';
 
{
  const ee = new EventEmitter();
  const listener = () => console.log('Events are fun');
  ee.on('foo', listener);
  console.log(getEventListeners(ee, 'foo')); // [ [Function: listener] ]
}
{
  const et = new EventTarget();
  const listener = () => console.log('Events are fun');
  et.addEventListener('foo', listener);
  console.log(getEventListeners(et, 'foo')); // [ [Function: listener] ]
}

Since

v15.2.0, v14.17.0

Icon LinkParameters

Icon LinkReturns

Function[]

Icon LinkInherited from

EventEmitter.getEventListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:358

Icon LinkgetMaxListeners

▸ getMaxListeners(emitter): number

Returns the currently set max amount of listeners.

For EventEmitters this behaves exactly the same as calling .getMaxListeners on the emitter.

For EventTargets this is the only way to get the max event listeners for the event target. If the number of event handlers on a single EventTarget exceeds the max set, the EventTarget will print a warning.

import { getMaxListeners, setMaxListeners, EventEmitter } from 'node:events';
 
{
  const ee = new EventEmitter();
  console.log(getMaxListeners(ee)); // 10
  setMaxListeners(11, ee);
  console.log(getMaxListeners(ee)); // 11
}
{
  const et = new EventTarget();
  console.log(getMaxListeners(et)); // 10
  setMaxListeners(11, et);
  console.log(getMaxListeners(et)); // 11
}

Since

v19.9.0

Icon LinkParameters

Icon LinkReturns

number

Icon LinkInherited from

EventEmitter.getMaxListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:387

Icon LinklistenerCount

▸ listenerCount(emitter, eventName): number

A class method that returns the number of listeners for the given eventName registered on the given emitter.

import { EventEmitter, listenerCount } from 'node:events';
 
const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// Prints: 2

Since

v0.9.12

Deprecated

Since v3.2.0 - Use listenerCount instead.

Icon LinkParameters

Icon LinkReturns

number

Icon LinkInherited from

EventEmitter.listenerCount

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:330

Icon Linkon

▸ on(emitter, eventName, options?): AsyncIterableIterator<any[]>

import { on, EventEmitter } from 'node:events';
import process from 'node:process';
 
const ee = new EventEmitter();
 
// Emit later on
process.nextTick(() => {
  ee.emit('foo', 'bar');
  ee.emit('foo', 42);
});
 
for await (const event of on(ee, 'foo')) {
  // The execution of this inner block is synchronous and it
  // processes one event at a time (even with await). Do not use
  // if concurrent execution is required.
  console.log(event); // prints ['bar'] [42]
}
// Unreachable here

Returns an AsyncIterator that iterates eventName events. It will throw if the EventEmitter emits 'error'. It removes all listeners when exiting the loop. The value returned by each iteration is an array composed of the emitted event arguments.

An AbortSignal can be used to cancel waiting on events:

import { on, EventEmitter } from 'node:events';
import process from 'node:process';
 
const ac = new AbortController();
 
(async () => {
  const ee = new EventEmitter();
 
  // Emit later on
  process.nextTick(() => {
    ee.emit('foo', 'bar');
    ee.emit('foo', 42);
  });
 
  for await (const event of on(ee, 'foo', { signal: ac.signal })) {
    // The execution of this inner block is synchronous and it
    // processes one event at a time (even with await). Do not use
    // if concurrent execution is required.
    console.log(event); // prints ['bar'] [42]
  }
  // Unreachable here
})();
 
process.nextTick(() => ac.abort());

Use the close option to specify an array of event names that will end the iteration:

import { on, EventEmitter } from 'node:events';
import process from 'node:process';
 
const ee = new EventEmitter();
 
// Emit later on
process.nextTick(() => {
  ee.emit('foo', 'bar');
  ee.emit('foo', 42);
  ee.emit('close');
});
 
for await (const event of on(ee, 'foo', { close: ['close'] })) {
  console.log(event); // prints ['bar'] [42]
}
// the loop will exit after 'close' is emitted
console.log('done'); // prints 'done'

Since

v13.6.0, v12.16.0

Icon LinkParameters

Icon LinkReturns

AsyncIterableIterator<any[]>

An AsyncIterator that iterates eventName events emitted by the emitter

Icon LinkInherited from

EventEmitter.on

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:303

▸ on(emitter, eventName, options?): AsyncIterableIterator<any[]>

Icon LinkParameters

Icon LinkReturns

AsyncIterableIterator<any[]>

Icon LinkInherited from

EventEmitter.on

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:308

Icon Linkonce

▸ once(emitter, eventName, options?): Promise<any[]>

Creates a Promise that is fulfilled when the EventEmitter emits the given event or that is rejected if the EventEmitter emits 'error' while waiting. The Promise will resolve with an array of all the arguments emitted to the given event.

This method is intentionally generic and works with the web platform EventTarget Icon Link interface, which has no special'error' event semantics and does not listen to the 'error' event.

import { once, EventEmitter } from 'node:events';
import process from 'node:process';
 
const ee = new EventEmitter();
 
process.nextTick(() => {
  ee.emit('myevent', 42);
});
 
const [value] = await once(ee, 'myevent');
console.log(value);
 
const err = new Error('kaboom');
process.nextTick(() => {
  ee.emit('error', err);
});
 
try {
  await once(ee, 'myevent');
} catch (err) {
  console.error('error happened', err);
}

The special handling of the 'error' event is only used when events.once() is used to wait for another event. If events.once() is used to wait for the 'error' event itself, then it is treated as any other kind of event without special handling:

import { EventEmitter, once } from 'node:events';
 
const ee = new EventEmitter();
 
once(ee, 'error')
  .then(([err]) => console.log('ok', err.message))
  .catch((err) => console.error('error', err.message));
 
ee.emit('error', new Error('boom'));
 
// Prints: ok boom

An AbortSignal can be used to cancel waiting for the event:

import { EventEmitter, once } from 'node:events';
 
const ee = new EventEmitter();
const ac = new AbortController();
 
async function foo(emitter, event, signal) {
  try {
    await once(emitter, event, { signal });
    console.log('event emitted!');
  } catch (error) {
    if (error.name === 'AbortError') {
      console.error('Waiting for the event was canceled!');
    } else {
      console.error('There was an error', error.message);
    }
  }
}
 
foo(ee, 'foo', ac.signal);
ac.abort(); // Abort waiting for the event
ee.emit('foo'); // Prints: Waiting for the event was canceled!

Since

v11.13.0, v10.16.0

Icon LinkParameters

Icon LinkReturns

Promise<any[]>

Icon LinkInherited from

EventEmitter.once

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:217

▸ once(emitter, eventName, options?): Promise<any[]>

Icon LinkParameters

Icon LinkReturns

Promise<any[]>

Icon LinkInherited from

EventEmitter.once

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:222

Icon LinksetMaxListeners

▸ setMaxListeners(n?, ...eventTargets): void

import { setMaxListeners, EventEmitter } from 'node:events';
 
const target = new EventTarget();
const emitter = new EventEmitter();
 
setMaxListeners(5, target, emitter);

Since

v15.4.0

Icon LinkParameters

Icon LinkReturns

void

Icon LinkInherited from

EventEmitter.setMaxListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@22.2.0/node_modules/@types/node/events.d.ts:402