# DowncastReduceChangesEvent

typedef

Fired to enable reducing (transforming) changes buffered in the [`Differ`](module_engine_model_differ-Differ.md) before [`convertChanges()`](module_engine_conversion_downcastdispatcher-DowncastDispatcher.md#function-convertChanges) will fire any conversion events.

For instance, a feature can replace selected [`DifferItem`](module_engine_model_differ-DifferItem.md)s with a `reinsert` entry to trigger reconversion of an element when e.g. its attribute has changes. The [\* `DowncastHelpers.elementToStructure()`](module_engine_conversion_downcasthelpers-DowncastHelpers.md#function-elementToStructure) helper is using this event to trigger reconversion of an element when the element, its attributes or direct children changed.

[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-engine/src/conversion/downcastdispatcher.ts#L726)

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## Properties

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### `args: [ data: DowncastReduceChangesEventData ]`

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### `name: 'reduceChanges'`

#### Value

`object`

## Fired by

* [DowncastDispatcher#reduceChanges](module_engine_conversion_downcastdispatcher-DowncastDispatcher.md#event-reduceChanges)

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Full index of the CKEditor 5 API reference: [llms.txt](llms.txt)