@forecasthq/react-virtualized-dnd NPM

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react-virtualized-dnd

react-virtualized-dnd is a React-based, fully virtualized drag-and-drop framework, enabling the the cross over of great user interaction and great performance. This project was made in response to the large amount of issues experienced trying to use virtualization libraries together with drag and drop libraries - react-virtualized-dnd does it all for you!

Check it out!

Install

npm install --save react-virtualized-dnd

Usage

React-Virtualized-DnD utilizes a three part abstraction for drag and drop:

A DragDropContext, which controls the overall flow and events of the drag and drop.
Draggables, which are wrappers for the elements you want to drag around.
Droppables, which indicate a drop zone that Draggables can be dropped on, and create the virtualizing container. Draggables and Droppables can be organized in groups.

Droppables use an internal scrollbar to virtualize its children, and the DragDropContext offers the option to include an outer scrollbar that can be scrolled while dragging. Addtionally, a DragScrollBar component is also available, which is a simple scroll container that reacts to drags and scroll near its edges.

React-virtualized-dnd places a placeholder in droppables during drag, which is placed after the draggable element hovered over during drag. The placeholderId represents the id of the element it was placed after. On drag end, the DragDropContext returns the placeholderId.

Example code can be seen below. A live example can be found at: https://forecast-it.github.io/react-virtualized-dnd/

import React, {Component} from 'react';
import ExampleBoard from 'react-virtualized-dnd';

class Example extends Component {
	render() {
      const name = 'my-group';
      const elemsToRender = [... your data here ...];
		return (
		  <DragDropContext dragAndDropGroup={name} onDragEnd={this.onDragEnd.bind(this)} outerScrollBar={true}>
			<div className={'your-drag-container'}>
			  {elemsToRender.map((elem, index) => (
				<div className={'your-droppable-container'}>
				  <Droppable dragAndDropGroup={name} droppableId={elem.droppableId} key={elem.droppableId}>
				    {elem.items.map(item => (
					  <Draggable dragAndDropGroup={name} draggableId={item.id}>
						<div className='your-draggable-element'>
						  <p>
						    {item.name}
						  </p>
						</div>
					  </Draggable>
					))}
				  </Droppable>
				</div>
			  ))}
			</div>
		  </DragDropContext>
		);
	}
}

Documentation & API

DragDropContext

Props

Prop	Type	Required	Description
dragAndDropGroup	string	yes	Unique identifier for the drag and drop group the context uses
outerScrollBar	boolean	no	Enables or disables global outer scrolling of the context (triggered by dragging)
scrollYSpeed	number	no	Custom scroll speed for global page scrolling (y-axis)
scrollXSpeed	number	no	Custom scroll speed for global page scrolling (x-axis)
autoScrollThreshold	number	no	Distance (in px) from the edges of the context where auto scroll is triggered during drag
scrollContainerHeight	number	no, yes with outerScrollBar	Height of the outer scrollable container
scrollContainerMinHeight	number	no	Minimum height of the outer scrollable container
onScroll	func	no	Function fired when the DragDropContext's outer scrollbar scrolls. Returns {scrollX, scrollY}
onDragEnd	function	no	Function fired on drag end with the source object, the droppableId of the destination, and the ID of the placeholder dropped on as params
onDragCancel	function	no	Function fired on drag end if the drop did not occur inside a droppable with the draggableId of the dragged element as params
onDragStart	function	no	Function fired on drag start with the draggableId of the dragged element as params

The placeholder ID can be used to determine where to place the dragged element on drag end. The placeholderID returns the string "END_OF_LIST" if dragged below the last element of a droppable.

Draggable

Props

Prop	Type	Required	Description
dragAndDropGroup	string	yes	Unique identifier for the drag and drop group the context uses
draggableId	string	yes	Unique identifier for the draggable
dragActiveClass	string	no	CSS class applied to a draggable element during an active drag
disabled	bool	no	Flag to disabled dragging of element
minDragDistanceThreshold	number	no	Minimum pixels a drag should move, before registering new elements dragged over (for updating placeholder). Defaults to 5px, increase for better performance, but fewer scans
usePointerEvents	bool	no	Flag to enable pointer-event based implementation. Experimental for now.

Draggables will ignore drags started by clicking on any element with the "no-drag" css class. This can be used to control drag interactions with interactive elements, such as inputs or buttons.

Droppable

Props

Prop	Type	Required	Description
dragAndDropGroup	string	yes	Unique identifier for the drag and drop group the context uses
droppableId	string	yes	Unique identifier for the droppable
containerHeight	Number	yes	Height of the virtualizing scroll container
placeholderStyle	Object	no	CSS style object to style the placeholder during drag
enforceContainerMinHeight	boolean	no	Force height of the droppable to always minimally match the containerHeight
rowHeight	Number	no	Height of each row with borders. Default is 50px.
disableScroll	boolean	no	Flag to disable scrollbars. This disables virtualization as well
listHeader	HTML element	no	Element to use as header for a droppable list, to react to drops on top of the list.
listHeaderHeight	Number	no (yes with listHeader)	Height of the header element, necessary for calculations.
activeHeaderClass	string	no	CSS class added to the header when an active drag is hovering over the list header
hideList	boolean	no	hides all droppable elements in the list
dynamicElemHeight	boolean	no	Flag to indicate differing/dynamicly changing heights of children elements.*
virtualizationThreshold	Number	no	Minimum number of elements in the list, before the virtualization kicks in. Useful if virtualizing very small lists produces flickers.
minElemHeight	Number	no (yes with dynamicElemHeight)	Minimum height of children elements. Necessary for calulating scrolling space.
customScrollbars	component	no	Component that uses forwardRef to generate scrollbars using react-custom-scrollbars
initialElemsToRender	Number	no	Number of elements to initially render. Defaults to an optimistic guess about the number of elements that can fit in the viewport.

*Enabling dynamic element height fundamentally changes how the scrolling works, and requries some more complex logic that is completely separate from the normal virtualization. If you experience issues with it, I recommend using the static element height approach, or trying to make the rendered children more similar in size.

Droppable

Props

Prop	Type	Required	Description
minHeight	Number	no	Minimum Height of the Scroll Container
maxHeight	Number	no	Maximum Height of the Scroll Container
autoScrollThreshold	Number	no	Distance (in px) from the edges of the scroll container where auto scroll is triggered during drag
onScroll	Function	no	Function fired when the Scrollbar scrolls. Returns {scrollX, scrollY}

Example Custom Scroll Bar

This component requires the usage of React's forwardRef to pass along the parent reference to the Scrollbars Element.
Please see react-custom-scrollbars for more information on how to customize a scrollbar.

Usage:

import {Scrollbars} from 'react-custom-scrollbars';

const CustomScrollBars = React.forwardRef((props, ref) => {
	const {children, ...rest} = props;
	return (
		<Scrollbars ref={ref} renderThumbVertical={({style, ...props}) => <div style={{...style, backgroundColor: 'blue'}} {...props} />} {...rest}>
			{children}
		</Scrollbars>
	);
});