@serenity-is/domwise / addDisposingListener

Function: addDisposingListener()

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

Defined in: src/disposing-listener.ts:130

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 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.