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FuelConnector

Icon LinkClass: FuelConnector

@fuel-ts/account .FuelConnector

FuelConnector

Wallet Connector is a interface that represents a Wallet Connector and all the methods that should be implemented to be compatible with the Fuel SDK.

Icon LinkHierarchy

  • EventEmitter

    FuelConnector

    ↳↳ Fuel

Icon LinkConstructors

Icon Linkconstructor

new FuelConnector(options?): FuelConnector

Icon LinkParameters

NameType
options?EventEmitterOptions

Icon LinkReturns

FuelConnector

Icon LinkInherited from

EventEmitter.constructor

Icon LinkDefined in

node_modules/.pnpm/@types+node@18.15.3/node_modules/@types/node/events.d.ts:111

Icon LinkProperties

Icon Linkconnected

connected: boolean = false

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:26 Icon Link


Icon Linkevents

events: typeof FuelConnectorEventTypes = FuelConnectorEventTypes

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:28 Icon Link


Icon Linkinstalled

installed: boolean = false

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:27 Icon Link


Icon Linkmetadata

metadata: ConnectorMetadata

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:25 Icon Link


Icon Linkname

name: string = ''

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:24 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 LinkMethods

Icon Linkaccounts

accounts(): Promise<string[]>

Should return all the accounts authorized for the current connection.

Icon LinkReturns

Promise<string[]>

The accounts addresses strings

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:66 Icon Link


Icon LinkaddABI

addABI(_contractId, _abi): Promise<boolean>

Should add the ABI to the connector and return true if the ABI was added successfully.

Icon LinkParameters

NameType
_contractIdstring
_abiJsonAbi

Icon LinkReturns

Promise<boolean>

Return true if the ABI was added successfully.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:237 Icon Link


Icon LinkaddAsset

addAsset(_asset): Promise<boolean>

Should add the the asset metadata to the connector and return true if the asset was added successfully.

If the asset already exists it should throw an error.

assets

Throws

Error if the asset already exists

Icon LinkParameters

NameType
_assetAsset

Icon LinkReturns

Promise<boolean>

True if the asset was added successfully

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:175 Icon Link


Icon LinkaddAssets

addAssets(_assets): Promise<boolean>

Should add the the assets metadata to the connector and return true if the asset was added successfully.

If the asset already exists it should throw an error.

assets

Throws

Error if the asset already exists

Icon LinkParameters

NameType
_assetsAsset []

Icon LinkReturns

Promise<boolean>

True if the asset was added successfully

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:160 Icon Link


Icon LinkaddListener

addListener(eventName, listener): FuelConnector

Alias for emitter.on(eventName, listener).

Since

v0.1.26

Icon LinkParameters

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Icon LinkReturns

FuelConnector

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 LinkaddNetwork

addNetwork(_networkUrl): Promise<boolean>

Should start the add network process and return true if the network was added successfully.

networks

Throws

Error if the network already exists

Icon LinkParameters

NameType
_networkUrlstring

Icon LinkReturns

Promise<boolean>

Return true if the network was added successfully

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:196 Icon Link


Icon Linkassets

assets(): Promise<Asset []>

Should return all the assets added to the connector. If a connection is already established.

Icon LinkReturns

Promise<Asset []>

Array of assets metadata from the connector vinculated to the all accounts from a specific Wallet.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:184 Icon Link


Icon Linkconnect

connect(): Promise<boolean>

Should start the connection process and return true if the account authorize the connection.

and return false if the user reject the connection.

accounts

Icon LinkReturns

Promise<boolean>

boolean - connection status.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:79 Icon Link


Icon LinkcurrentAccount

currentAccount(): Promise<null | string>

Should return the current account selected inside the connector, if the account is authorized for the connection.

If the account is not authorized it should return null.

Icon LinkReturns

Promise<null | string>

The current account selected otherwise null.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:145 Icon Link


Icon LinkcurrentNetwork

currentNetwork(): Promise<Network >

Should return the current network selected inside the connector. Even if the connection is not established.

Icon LinkReturns

Promise<Network >

Return the current network selected inside the connector.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:226 Icon Link


Icon Linkdisconnect

disconnect(): Promise<boolean>

Should disconnect the current connection and return false if the disconnection was successful.

assets connection

Icon LinkReturns

Promise<boolean>

The connection status.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:90 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

NameType
eventNamestring | symbol
...argsany[]

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 LinkgetABI

getABI(_id): Promise<null | JsonAbi>

Should return the ABI from the connector vinculated to the all accounts from a specific Wallet.

Icon LinkParameters

NameType
_idstring

Icon LinkReturns

Promise<null | JsonAbi>

The ABI if it exists, otherwise return null.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:247 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 LinkhasABI

hasABI(_id): Promise<boolean>

Should return true if the abi exists in the connector vinculated to the all accounts from a specific Wallet.

Icon LinkParameters

NameType
_idstring

Icon LinkReturns

Promise<boolean>

Returns true if the abi exists or false if not.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:257 Icon Link


Icon LinkisConnected

isConnected(): Promise<boolean>

Should return true if the connector is connected to any of the accounts available.

Icon LinkReturns

Promise<boolean>

The connection status.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:56 Icon Link


Icon LinklistenerCount

listenerCount(eventName): number

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

Since

v3.2.0

Icon LinkParameters

NameTypeDescription
eventNamestring | symbolThe name of the event being listened for

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

NameType
eventNamestring | symbol

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 Linknetworks

networks(): Promise<Network []>

Should return all the networks available from the connector. If the connection is already established.

Icon LinkReturns

Promise<Network []>

Return all the networks added to the connector.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:217 Icon Link


Icon Linkoff

off(eventName, listener): FuelConnector

Alias for emitter.removeListener().

Since

v10.0.0

Icon LinkParameters

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Icon LinkReturns

FuelConnector

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<E, D>(eventName, listener): FuelConnector

Event listener for the connector.

Icon LinkType parameters

Icon LinkParameters

NameTypeDescription
eventNameEThe event name to listen
listener(data: D) => voidThe listener function

Icon LinkReturns

FuelConnector

Icon LinkOverrides

EventEmitter.on

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:267 Icon Link


Icon Linkonce

once(eventName, listener): FuelConnector

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

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Icon LinkReturns

FuelConnector

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 Linkping

ping(): Promise<boolean>

Should return true if the connector is loaded in less then one second.

Icon LinkReturns

Promise<boolean>

Always true.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:36 Icon Link


Icon LinkprependListener

prependListener(eventName, listener): FuelConnector

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

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Icon LinkReturns

FuelConnector

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): FuelConnector

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

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Icon LinkReturns

FuelConnector

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

NameType
eventNamestring | symbol

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?): FuelConnector

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

NameType
event?string | symbol

Icon LinkReturns

FuelConnector

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): FuelConnector

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

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Icon LinkReturns

FuelConnector

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 LinkselectNetwork

selectNetwork(_network): Promise<boolean>

Should start the select network process and return true if the network has change successfully.

networks

Throws

Error if the network already exists

Icon LinkParameters

NameType
_networkNetwork

Icon LinkReturns

Promise<boolean>

Return true if the network was added successfully

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:208 Icon Link


Icon LinksendTransaction

sendTransaction(_address, _transaction): Promise<string>

Should start the send transaction process and return the transaction id submitted to the network.

If the network is not available for the connection it should throw an error to avoid the transaction to be sent to the wrong network and lost.

Icon LinkParameters

NameType
_addressstring
_transactionTransactionRequestLike

Icon LinkReturns

Promise<string>

The transaction id

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:133 Icon Link


Icon LinksetMaxListeners

setMaxListeners(n): FuelConnector

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

NameType
nnumber

Icon LinkReturns

FuelConnector

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 LinksignMessage

signMessage(_address, _message): Promise<string>

Should start the sign message process and return the signed message.

Icon LinkParameters

NameType
_addressstring
_messagestring

Icon LinkReturns

Promise<string>

Message signature

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:103 Icon Link


Icon LinksignTransaction

signTransaction(_address, _transaction): Promise<string>

Should start the sign transaction process and return the signed transaction.

Icon LinkParameters

NameType
_addressstring
_transactionTransactionRequestLike

Icon LinkReturns

Promise<string>

Transaction signature

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:116 Icon Link


Icon Linkversion

version(): Promise<Version >

Should return the current version of the connector and the network version that is compatible.

Icon LinkReturns

Promise<Version >

boolean - connection status.

Icon LinkDefined in

packages/account/src/connectors/fuel-connector.ts:46 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

NameType
emitterEventEmitter | _DOMEventTarget
namestring | symbol

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

NameTypeDescription
emitterEventEmitterThe emitter to query
eventNamestring | symbolThe event name

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

NameTypeDescription
emitterEventEmitter-
eventNamestringThe name of the event being listened for
options?StaticEventEmitterOptions-

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

NameType
emitter_NodeEventTarget
eventNamestring | symbol
options?StaticEventEmitterOptions

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

NameType
emitter_DOMEventTarget
eventNamestring
options?StaticEventEmitterOptions

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

NameTypeDescription
n?numberA non-negative number. The maximum number of listeners per EventTarget event.
...eventTargets(EventEmitter | _DOMEventTarget)[]-

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