Implement onDragOverEnter & onDragOverLeave

Author: haywirez

docs/API/events.mdx

@@ -15,6 +15,8 @@ Also notice the `onPointerMissed` on the canvas element, which fires on clicks t
   onClick={(e) => console.log('click')}
   onContextMenu={(e) => console.log('context menu')}
   onDoubleClick={(e) => console.log('double click')}
+  onDragOverEnter={(e) => console.log('dragover enter')}
+  onDragOverLeave={(e) => console.log('dragover leave')}
   onWheel={(e) => console.log('wheel spins')}
   onPointerUp={(e) => console.log('up')}
   onPointerDown={(e) => console.log('down')}

packages/fiber/src/core/events.ts

@@ -41,6 +41,8 @@ export type Events = {
   onClick: EventListener
   onContextMenu: EventListener
   onDoubleClick: EventListener
+  onDragOverEnter: EventListener
+  onDragOverLeave: EventListener
   onWheel: EventListener
   onPointerDown: EventListener
   onPointerUp: EventListener
@@ -54,6 +56,8 @@ export type EventHandlers = {
   onClick?: (event: ThreeEvent<MouseEvent>) => void
   onContextMenu?: (event: ThreeEvent<MouseEvent>) => void
   onDoubleClick?: (event: ThreeEvent<MouseEvent>) => void
+  onDragOverEnter?: (event: ThreeEvent<DragEvent>) => void
+  onDragOverLeave?: (event: DragEvent) => void
   onPointerUp?: (event: ThreeEvent<PointerEvent>) => void
   onPointerDown?: (event: ThreeEvent<PointerEvent>) => void
   onPointerOver?: (event: ThreeEvent<PointerEvent>) => void
@@ -109,6 +113,7 @@ export function getEventPriority() {
     case 'pointerdown':
     case 'pointerup':
       return DiscreteEventPriority
+    case 'dragover':
     case 'pointermove':
     case 'pointerout':
     case 'pointerover':
@@ -171,10 +176,12 @@ export function createEvents(store: UseBoundStore<RootState>) {
 
   /** Returns true if an instance has a valid pointer-event registered, this excludes scroll, clicks etc */
   function filterPointerEvents(objects: THREE.Object3D[]) {
-    return objects.filter((obj) =>
-      ['Move', 'Over', 'Enter', 'Out', 'Leave'].some(
-        (name) => (obj as unknown as Instance).__r3f?.handlers[('onPointer' + name) as keyof EventHandlers],
-      ),
+    return objects.filter(
+      (obj) =>
+        ['Move', 'Over', 'Enter', 'Out', 'Leave'].some(
+          (name) => (obj as unknown as Instance).__r3f?.handlers[('onPointer' + name) as keyof EventHandlers],
+        ) ||
+        ['Over'].some((name) => (obj as unknown as Instance).__r3f?.handlers[('onDrag' + name) as keyof EventHandlers]),
     )
   }
 
@@ -377,6 +384,8 @@ export function createEvents(store: UseBoundStore<RootState>) {
           const data = { ...hoveredObj, intersections }
           handlers.onPointerOut?.(data as ThreeEvent<PointerEvent>)
           handlers.onPointerLeave?.(data as ThreeEvent<PointerEvent>)
+          // @ts-ignore
+          handlers.onDragOverLeave?.(data)
         }
       }
     })
@@ -409,6 +418,7 @@ export function createEvents(store: UseBoundStore<RootState>) {
 
       // Get fresh intersects
       const isPointerMove = name === 'onPointerMove'
+      const isDragOver = name === 'onDragOverEnter' || name === 'onDragOverLeave'
       const isClickEvent = name === 'onClick' || name === 'onContextMenu' || name === 'onDoubleClick'
       const filter = isPointerMove ? filterPointerEvents : undefined
       //const hits = patchIntersects(intersect(filter), event)
@@ -430,7 +440,7 @@ export function createEvents(store: UseBoundStore<RootState>) {
         }
       }
       // Take care of unhover
-      if (isPointerMove) cancelPointer(hits)
+      if (isPointerMove || isDragOver) cancelPointer(hits)
 
       handleIntersects(hits, event, delta, (data: ThreeEvent<DomEvent>) => {
         const eventObject = data.eventObject
@@ -457,6 +467,18 @@ export function createEvents(store: UseBoundStore<RootState>) {
           }
           // Call mouse move
           handlers.onPointerMove?.(data as ThreeEvent<PointerEvent>)
+        } else if (isDragOver) {
+          // When enter or out is present take care of hover-state
+          const id = makeId(data)
+          const hoveredItem = internal.hovered.get(id)
+          if (!hoveredItem) {
+            // If the object wasn't previously hovered, book it and call its handler
+            internal.hovered.set(id, data)
+            handlers.onDragOverEnter?.(data as ThreeEvent<DragEvent>)
+          } else if (hoveredItem.stopped) {
+            // If the object was previously hovered and stopped, we shouldn't allow other items to proceed
+            data.stopPropagation()
+          }
         } else {
           // All other events ...
           const handler = handlers[name as keyof EventHandlers] as (event: ThreeEvent<PointerEvent>) => void

packages/fiber/src/core/utils.ts

@@ -219,7 +219,8 @@ export function diffProps(
     // When props match bail out
     if (is.equ(value, previous[key])) return
     // Collect handlers and bail out
-    if (/^on(Pointer|Click|DoubleClick|ContextMenu|Wheel)/.test(key)) return changes.push([key, value, true, []])
+    if (/^on(Pointer|DragOver|Click|DoubleClick|ContextMenu|Wheel)/.test(key))
+      return changes.push([key, value, true, []])
     // Split dashed props
     let entries: string[] = []
     if (key.includes('-')) entries = key.split('-')

packages/fiber/src/web/events.ts

@@ -6,6 +6,8 @@ const DOM_EVENTS = {
   onClick: ['click', false],
   onContextMenu: ['contextmenu', false],
   onDoubleClick: ['dblclick', false],
+  onDragOverEnter: ['dragover', true],
+  onDragOverLeave: ['dragover', true],
   onWheel: ['wheel', true],
   onPointerDown: ['pointerdown', true],
   onPointerUp: ['pointerup', true],

packages/fiber/tests/core/events.test.tsx

@@ -1,5 +1,5 @@
 import * as React from 'react'
-import { render, fireEvent, RenderResult } from '@testing-library/react'
+import { render, fireEvent, createEvent, RenderResult } from '@testing-library/react'
 
 import { Canvas, act } from '../../src'
 
@@ -210,6 +210,44 @@ describe('events', () => {
     expect(handlePointerOut).toHaveBeenCalled()
   })
 
+  it('can handle onDragOverEnter & onDragOverLeave', async () => {
+    const handleDragOverEnter = jest.fn()
+    const handleDragOverLeave = jest.fn()
+
+    await act(async () => {
+      render(
+        <Canvas>
+          <mesh onDragOverEnter={handleDragOverEnter} onDragOverLeave={handleDragOverLeave}>
+            <boxGeometry args={[2, 2]} />
+            <meshBasicMaterial />
+          </mesh>
+        </Canvas>,
+      )
+    })
+
+    // Note: DragEvent is not implemented in jsdom yet: https://github.com/jsdom/jsdom/issues/2913
+    // https://developer.mozilla.org/en-US/docs/Web/API/DragEvent
+    // however, @react-testing/library does simulate it
+    let evt = createEvent.dragOver(getContainer())
+    //@ts-ignore
+    evt.offsetX = 577
+    //@ts-ignore
+    evt.offsetY = 480
+
+    fireEvent(getContainer(), evt)
+
+    expect(handleDragOverEnter).toHaveBeenCalled()
+
+    // pretend we moved out over from the target
+    //@ts-ignore
+    evt.offsetX = 1
+    //@ts-ignore
+    evt.offsetY = 1
+    fireEvent(getContainer(), evt)
+
+    expect(handleDragOverLeave).toHaveBeenCalled()
+  })
+
   it('should handle stopPropagation', async () => {
     const handlePointerEnter = jest.fn().mockImplementation((e) => {
       expect(() => e.stopPropagation()).not.toThrow()