Class EventEmitter<TArg>

Expose ability to emit and subscribe to a single type of event.

Type Parameters

TArg = void
type of the event payload.

Index

Constructors

Methods

invoke invokeAsync subscribe

Constructors

constructor

new EventEmitter<TArg = void>(): EventEmitter<TArg>
Type Parameters
- TArg = void
Returns EventEmitter<TArg>

Methods

invoke

invoke(arg: TArg): void
Fires the event.
Parameters
- arg: TArg
  event payload.
Returns void
Remarks
- This function will asynchronously wait for all its event handlers to return (or throw) before returning, but will not await any asynchronous portions.
- Were any of the event handler to throw any error, this function would not throw. Instead, errors are thrown to the current SynchronizationContext.
- Defined in packages/jscorlib/src/events/eventEmitter.ts:46

invokeAsync

invokeAsync(arg: TArg): Promise<void>
Fires the event asynchronously.
Parameters
- arg: TArg
  event payload.
Returns Promise<void>
Remarks
- This function will wait for all its event handlers to return (or throw) before returning, and will await any asynchronous portions.
- Were any of the event handler to throw any error, this function would not throw. Instead, errors are thrown to the current SynchronizationContext.
- Defined in packages/jscorlib/src/events/eventEmitter.ts:68

subscribe(handler: EventHandler<TArg>): Disposable
Subscribes to the event.
Parameters
- handler: EventHandler<TArg>
  a function to call when the event has been fired.
Returns Disposable
a token used to cancel the event subscription.
Remarks
- Subscribing the same handler multiple times is allowed; they will be invoked multiple times.
- If handler returns a PromiseLike value, depending on how the EventEmitter.invokeAsync is called, your event handler might be called concurrently (the 2nd invocation starts before the 1st invocation ends).
Todo
Set up convention on what should happen if a handler is added/removed while the event is being fired.
- Defined in packages/jscorlib/src/events/eventEmitter.ts:21