event.preventDefault() in onKeyDown does not prevent Slate's default behavior.

[BiosSun]

Description

When using event.preventDefault() inside an onKeyDown handler in a Plate plugin, it does not stop Slate's default behavior as expected. For example, consider the following plugin:

createPlatePlugin({
    key: 'myPlugin',
    handlers: {
        onKeyDown({ editor, event }) {
            if (Hotkeys.isMoveBackward(event)) {
                event.preventDefault()
                // Custom logic here
            }
        },
    },
})

I believe the issue is caused by the following line of code in pipeHandler.ts:

plate/packages/core/src/react/utils/pipeHandler.ts

Lines 42 to 61 in e985bfe

	export const isEventHandled = <
	EventType extends React.SyntheticEvent<unknown, unknown>,
	>(
	event: EventType,
	handler?: (event: EventType) => boolean | void
	) => {
	if (!handler) {
	return false;
	}
	// The custom event handler may return a boolean to specify whether the event
	// shall be treated as being handled or not.
	const shouldTreatEventAsHandled = handler(event);
	if (shouldTreatEventAsHandled != null) {
	return shouldTreatEventAsHandled;
	}
	return event.isPropagationStopped();
	};

Currently, the condition is:

return event.isPropagationStopped();

However, it should also check whether the default action has been prevented, like this:

return event.isDefaultPrevented() || event.isPropagationStopped();

This behavior was correct in earlier versions but was changed in this commit. I'm not sure of the rationale behind this modification, but it seems to have introduced the issue.

Reproduction URL

No response

Steps to Reproduce

1. Create a plugin with an onKeyDown handler that calls event.preventDefault().
2. Trigger the handler by pressing the corresponding key (e.g., a key mapped to Hotkeys.isMoveBackward).
3. Observe that Slate's default behavior is not prevented.

Plate version

42.0.1

Slate React version

0.112.0

Browsers

No response

[zbeyens]

@12joan do you have some thoughts on that?

[12joan]

It sounds like event.preventDefault() definitely ought to work the way you expect. The commit that removed this behaviour is three and a half years old, so it's quite likely that the reason for this change is no longer relevant. Shall we reinstante it?