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

Icon LinkInherited from

EventEmitter.captureRejectionSymbol

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:328

Icon LinkcaptureRejections

▪ Static captureRejections: boolean

Sets or gets the default captureRejection value for all emitters.

Icon LinkInherited from

EventEmitter.captureRejections

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:333

Icon LinkdefaultMaxListeners

▪ Static defaultMaxListeners: number

Icon LinkInherited from

EventEmitter.defaultMaxListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:334

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.

Icon LinkInherited from

EventEmitter.errorMonitor

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:327

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 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(eventName, listener): WalletManager

Alias for emitter.on(eventName, listener).

Since

v0.1.26

Icon LinkParameters

Icon LinkReturns

WalletManager

Icon LinkInherited from

EventEmitter.addListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:354

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(eventName, ...args): boolean

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

Returns true if the event had listeners, false otherwise.

const EventEmitter = require('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 LinkParameters

Icon LinkReturns

boolean

Icon LinkInherited from

EventEmitter.emit

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:610

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.

const EventEmitter = require('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@18.15.3/node_modules/@types/node/events.d.ts:669

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@18.15.3/node_modules/@types/node/events.d.ts:526

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(eventName): number

Returns the number of listeners listening to the event named eventName.

Since

v3.2.0

Icon LinkParameters

Icon LinkReturns

number

Icon LinkInherited from

EventEmitter.listenerCount

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:616

Icon Linklisteners

▸ listeners(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 LinkParameters

Icon LinkReturns

Function[]

Icon LinkInherited from

EventEmitter.listeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:539

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(eventName, listener): WalletManager

Alias for emitter.removeListener().

Since

v10.0.0

Icon LinkParameters

Icon LinkReturns

WalletManager

Icon LinkInherited from

EventEmitter.off

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:499

Icon Linkon

▸ on(eventName, listener): WalletManager

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 eventNameand 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. Theemitter.prependListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

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 LinkParameters

Icon LinkReturns

WalletManager

Icon LinkInherited from

EventEmitter.on

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:385

Icon Linkonce

▸ once(eventName, listener): WalletManager

Adds a one-timelistener 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. Theemitter.prependOnceListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

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 LinkParameters

Icon LinkReturns

WalletManager

Icon LinkInherited from

EventEmitter.once

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:414

Icon LinkprependListener

▸ prependListener(eventName, listener): WalletManager

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 eventNameand 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 LinkParameters

Icon LinkReturns

WalletManager

Icon LinkInherited from

EventEmitter.prependListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:634

Icon LinkprependOnceListener

▸ prependOnceListener(eventName, listener): WalletManager

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 LinkParameters

Icon LinkReturns

WalletManager

Icon LinkInherited from

EventEmitter.prependOnceListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:650

Icon LinkrawListeners

▸ rawListeners(eventName): Function[]

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

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 LinkParameters

Icon LinkReturns

Function[]

Icon LinkInherited from

EventEmitter.rawListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:569

Icon LinkremoveAllListeners

▸ removeAllListeners(event?): WalletManager

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

WalletManager

Icon LinkInherited from

EventEmitter.removeAllListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:510

Icon LinkremoveListener

▸ removeListener(eventName, listener): WalletManager

Removes the specified listener from the listener array for the event namedeventName.

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 anyremoveListener() or removeAllListeners() calls after emitting and before the last listener finishes execution will not remove them fromemit() in progress. Subsequent events behave as expected.

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:

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 LinkParameters

Icon LinkReturns

WalletManager

Icon LinkInherited from

EventEmitter.removeListener

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:494

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): WalletManager

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 toInfinity (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

WalletManager

Icon LinkInherited from

EventEmitter.setMaxListeners

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:520

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 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.

const { getEventListeners, EventEmitter } = require('events');
 
{
  const ee = new EventEmitter();
  const listener = () => console.log('Events are fun');
  ee.on('foo', listener);
  getEventListeners(ee, 'foo'); // [listener]
}
{
  const et = new EventTarget();
  const listener = () => console.log('Events are fun');
  et.addEventListener('foo', listener);
  getEventListeners(et, 'foo'); // [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@18.15.3/node_modules/@types/node/events.d.ts:299

Icon LinklistenerCount

▸ listenerCount(emitter, eventName): number

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

const { EventEmitter, listenerCount } = require('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@18.15.3/node_modules/@types/node/events.d.ts:271

Icon Linkon

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

const { on, EventEmitter } = require('events');
 
(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')) {
    // 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:

const { on, EventEmitter } = require('events');
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());

Since

v13.6.0, v12.16.0

Icon LinkParameters

Icon LinkReturns

AsyncIterableIterator<any>

that iterates eventName events emitted by the emitter

Icon LinkInherited from

EventEmitter.on

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:254

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.

const { once, EventEmitter } = require('events');
 
async function run() {
  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.log('error happened', err);
  }
}
 
run();

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:

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

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

const { EventEmitter, once } = require('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@18.15.3/node_modules/@types/node/events.d.ts:194

▸ 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@18.15.3/node_modules/@types/node/events.d.ts:195

Icon LinksetMaxListeners

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

const {
  setMaxListeners,
  EventEmitter
} = require('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@18.15.3/node_modules/@types/node/events.d.ts:317