Optionaloptions: EventEmitterOptionsSynchronously calls each of the listeners registered for the event named
event, in the order they were registered, passing the supplied arguments
to each.
The name of the event to emit
Rest...args: Parameters<SuperclassArguments[T]>Arguments to pass to the listener
true if the event had listeners, false otherwise.
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.
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
Rest...args: Parameters<Arguments[T]>Similar to emit but calls all listeners within a Promise.all and returns the promise chain
The name of the event to emit
Rest...args: Parameters<SuperclassArguments[T]>Arguments to pass to the listener
true if the event had listeners, false otherwise.
Rest...args: Parameters<Arguments[T]>Returns the number of listeners listening to the event named event.
The name of the event being listened for
Returns a copy of the array of listeners for the event named event.
Alias for removeListener
Adds the listener function to the end of the listeners array for the
event named event.
No checks are made to see if the listener has already been added. Multiple calls
passing the same combination of event and listener will result in the listener
being added, and called, multiple times.
By default, event listeners are invoked in the order they are added. The prependListener method can be used as an alternative to add the event listener to the beginning of the listeners array.
a reference to the EventEmitter, so that calls can be chained.
Adds a one-time listener function for the event named event. The
next time event is triggered, this listener is removed and then invoked.
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 prependOnceListener method can be used as an alternative to add the event listener to the beginning of the listeners array.
a reference to the EventEmitter, so that calls can be chained.
Adds the listener function to the beginning of the listeners array for the
event named event.
No checks are made to see if the listener has already been added. Multiple calls
passing the same combination of event and listener will result in the listener
being added, and called, multiple times.
a reference to the EventEmitter, so that calls can be chained.
Adds a one-timelistener function for the event named event to the beginning of the listeners array.
The next time event is triggered, this listener is removed, and then invoked.
a reference to the EventEmitter, so that calls can be chained.
Returns a copy of the array of listeners for the event named eventName,
including any wrappers (such as those created by .once()).
Removes all listeners, or those of the specified event.
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).
Optionalevent: EventEmitterEvents | EventsThe name of the event. If undefined, all listeners everywhere are removed.
a reference to the EventEmitter, so that calls can be chained.
Removes the specified listener from the listener array for the event named event.
a reference to the EventEmitter, so that calls can be chained.
Typed Event Emitter class which can act as a Base Model for all our model and communication events. This makes it much easier for us to distinguish between events, as we now need to properly type this, so that our events are not stringly-based and prone to silly typos.
Type parameters:
Events- List of all events emitted by thisTypedEventEmitter. Normally an enum type.Arguments- A ListenerMap type providing mappings from event names to listener types.SuperclassArguments- TODO: not really sure. Alternative listener mappings, I think? But only honoured for.emit?