@serenity-is/domwise / addDisposingListener

Function: addDisposingListener()

addDisposingListener<T>(target, handler, regKey?): T | null | undefined

Defined in: src/disposing-listener.ts:118

Registers a disposing listener for an element.

The handler is not added as a direct DOM event listener; instead it is stored in an internal WeakMap and invoked when a disposing event is dispatched on target (via dispatchDisposingEvent or invokeDisposingListeners). The first registration on a given target also installs a one-shot disposing event listener to drive the callback list. Duplicate handler references are ignored (with optional regKey tracking), so calling this multiple times with the same callback is safe.

Type Parameters

T

T extends EventTarget

Type of the target event target.

Parameters

target

Element/event target to attach the listener to. No-op when null/undefined.

T | null | undefined

handler

Callback invoked with the element when it is disposing. No-op when null/undefined.

(el) => void | null | undefined

regKey?

string

Optional registration key used to de-duplicate or later remove this listener.

Returns

T | null | undefined

The target that was passed in, for chaining.

Throws

When the same handler is already registered with a different regKey.