Event Emitter

Overview

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The Event Emitter (PyEventsEmitter) is a powerful tool for managing event listeners and emitting events in your application. It provides a range of methods for adding, removing, and checking listeners, as well as emitting events with arguments.

Installation

pip install PyEventsEmitter

Initialization

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__init__(options: Optional[Dict[str, Any]] | None) -> None

Initializes a new instance of the Event Emitter class. The options parameter is an optional dictionary containing configuration options for the Event Emitter. If provided, the captureRejections flag is set to the value of the 'captureRejections' key in the options dictionary. If the 'captureRejections' key is not present in the options dictionary, or if options is None, the captureRejections flag is set to False.

events and captureRejections Attributes

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• events: A dictionary storing event listeners.

• captureRejections: A flag indicating whether the Event Emitter captures and emits rejections.

Methods

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on(event_name: str, listener: Callable[..., None]) -> None

Adds a listener to the specified event.

off(event_name: str, listener: Callable[..., None]) -> None

Removes a listener from the specified event.

emit(event_name: str, *args: Any) -> self

Emits an event with the given name and arguments.

once(event_name: str, listener: Callable[..., None]) -> self

Adds a listener to the specified event that will be executed only once.

listeners(event_name: str) -> List[Callable[..., None]]

Returns a list of listeners for the specified event name.

listener_count(event_name: str) -> int

Returns the number of listeners for the specified event name.

remove_listener(event_name: str, listener: Callable[..., None]) -> self

Removes a listener from the specified event.

remove_all_listeners(event_name: Optional[str] = None) -> self

Removes all listeners for the specified event or all events if no event name is provided.

set_max_listeners(n: int) -> self

Sets the maximum number of listeners for the event emitter.

get_max_listeners() -> int

Returns the maximum number of listeners for the event emitter.

prependListener(event_name: str, listener: Callable[..., None]) -> self

Adds a listener to the beginning of the listeners array for the specified event.

prependOnceListener(event_name: str, listener: Callable[..., None]) -> self

Adds a one-time listener function to the beginning of the listeners array for the specified event.

event_names() -> List[str]

Returns a list of event names.

addAbortListener(signal: AbortSignal, resource: Callable[[str], None]) -> Disposable

Adds an abort listener to the event emitter.

captureRejection() -> bool

Gets the current setting for capturing rejection events.

defaultMaxListeners() -> int

Returns the default maximum number of listeners allowed per event.