react-dnd#ConnectDragPreview TypeScript Examples

The following examples show how to use react-dnd#ConnectDragPreview. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example #1
Source File: useDraggable.ts    From ui-schema with MIT License 4 votes vote down vote up 
useDraggable = <C extends HTMLElement = HTMLElement, S extends ItemSpec = ItemSpec>(
    {
        item,
        allowedTypes,
        scope: localScope,
        refRoot,
    }: {
        item: S
        allowedTypes: string[] | List<string> | undefined
        scope?: string
        refRoot: React.MutableRefObject<C | null>
    }
): {
    isOver: boolean
    canDrop: boolean
    drop: ConnectDropTarget
    isDragging: boolean
    drag: ConnectDragSource
    preview: ConnectDragPreview
    setDisableDrag: React.Dispatch<React.SetStateAction<boolean>>
    canDrag: boolean
} => {
    const [disableDrag, setDisableDrag] = React.useState<boolean>(false)
    const {onMove, scope} = useKitDnd<C>()

    const [{isOver, canDrop}, drop] = useDrop<S, S, { handlerId: (Identifier | null), isOver: boolean, canDrop: boolean }>(() => ({
        accept: localScope ? localScope : (scope ? '_' + scope : '_') as string,
        options: {},
        collect: (monitor: DropTargetMonitor<C>) => ({
            isOver: monitor.isOver({shallow: true}),
            canDrop: monitor.canDrop(),
            handlerId: monitor.getHandlerId(),
        }),
        canDrop: (fromItem: S, monitor: DropTargetMonitor<C>) => {
            if (!monitor.isOver({shallow: true})) {
                return false
            }
            return (
                !fromItem.dataKeys.push(fromItem.index).equals(item.dataKeys.push(item.index)) &&
                fromItem.id !== item.id
            ) && (
                !allowedTypes ||
                allowedTypes.indexOf(fromItem.type) !== -1
            )
        },
        hover(fromItem: S, monitor: DropTargetMonitor<C>) {
            if (monitor.canDrop()) {
                onMove({
                    targetElement: refRoot.current as C,
                    toItem: item as unknown as S,
                    fromItem: fromItem as unknown as S,
                    monitor,
                })
            }
        },
    }), [item, localScope, scope, allowedTypes, refRoot])

    const [{canDrag, isDragging}, drag, preview] = useDrag<S, S, { isDragging: boolean, canDrag: boolean }>(() => ({
        type: localScope ? localScope : (scope ? '_' + scope : '_') as string,
        item: {...item},
        collect: (monitor: DragSourceMonitor<S>) => ({
            isDragging: monitor.isDragging(),
            canDrag: monitor.canDrag(),
        }),
        canDrag: () => {
            return !disableDrag
        },
        isDragging: (monitor: DragSourceMonitor<S>) => {
            const {index, dataKeys} = item
            const tmpItem = monitor.getItem() as S
            if (!tmpItem) return false
            let itemDataKeys = tmpItem.dataKeys as List<number>
            if (!List.isList(itemDataKeys)) {
                itemDataKeys = List(itemDataKeys) as List<number>
            }
            return tmpItem.dataKeys.push(tmpItem.index).equals(dataKeys.push(index)) &&
                itemDataKeys.equals(!List.isList(dataKeys) ? List(dataKeys) : dataKeys)
        },
    }), [
        item, localScope, scope, disableDrag,
    ])

    return {
        isOver, canDrop, drop,
        isDragging, drag, preview,
        setDisableDrag,
        // todo: somehow `canDrag` isn't `false` when it is internally `false`
        canDrag: canDrag && !disableDrag,
    }
}