Sortable

The sortable preset provides the building blocks to build sortable interfaces.

Installation

To get started, install the sortable preset via npm or yarn:

npm install @dnd-kit/sortable

Overview

If you're eager to get started right away, here's the code you'll need:

App.jsx

import React, {useState} from 'react';
import {
  DndContext, 
  closestCenter,
  KeyboardSensor,
  PointerSensor,
  useSensor,
  useSensors,
} from '@dnd-kit/core';
import {
  arrayMove,
  SortableContext,
  sortableKeyboardCoordinates,
  verticalListSortingStrategy,
} from '@dnd-kit/sortable';

import {SortableItem} from './SortableItem';

function App() {
  const [items, setItems] = useState([1, 2, 3]);
  const sensors = useSensors(
    useSensor(PointerSensor),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    })
  );

  return (
    <DndContext 
      sensors={sensors}
      collisionDetection={closestCenter}
      onDragEnd={handleDragEnd}
    >
      <SortableContext 
        items={items}
        strategy={verticalListSortingStrategy}
      >
        {items.map(id => <SortableItem key={id} id={id} />)}
      </SortableContext>
    </DndContext>
  );
  
  function handleDragEnd(event) {
    const {active, over} = event;
    
    if (active.id !== over.id) {
      setItems((items) => {
        const oldIndex = items.indexOf(active.id);
        const newIndex = items.indexOf(over.id);
        
        return arrayMove(items, oldIndex, newIndex);
      });
    }
  }
}

SortableItem.jsx

For most sortable lists, we recommend you use a DragOverlay if your sortable list is scrollable or if the contents of the scrollable list are taller than the viewport of the window. Check out the sortable drag overlay guide below to learn more.

Architecture

The sortable preset builds on top of the primitives exposed by @dnd-kit/core to help building sortable interfaces.

The sortable preset exposes two main concepts: SortableContext and the useSortable hook:

• The SortableContext provides information via context that is consumed by the useSortable hook.

• The useSortable hook is an abstraction that composes the useDroppable and useDraggable hooks:

Single container

At a high level, the application structure to implement a sortable list with a single container looks as follows:

Multiple containers

To implement sortable list with items that can be dropped within multiple containers, the application structure is the same, but we add as many SortableContext providers as we have containers:

In this example, we would use the onDragOver callback of DndContext to detect when a draggable element is moved over a different container to insert it in that new container while dragging.

If you paid close attention to the illustration above, you may also have noticed that we added a droppable zone around each sortable context. This isn't required, but will likely be the behaviour most people want. If you move all sortable items from one column into the other, you will need a droppable zone for the empty column so that you may drag sortable items back into that empty column:

Concepts

Sortable Context

In addition to the DndContext provider, the Sortable preset requires its own context provider that contains the sorted array of the unique identifiers associated to each sortable item:

import React, {useState} from 'react';
import {DndContext} from '@dnd-kit/core';
import {SortableContext} from '@dnd-kit/sortable';

function App() {
  const [items] = useState(['1', '2', '3']);

  return (
    <DndContext>
      <SortableContext items={items}>
        {/* ... */}
      </SortableContext>
    </DndContext>
  );
}

The SortableContext provides information via context that is consumed by the useSortable hook, which is covered in greater detail in the next section.

It's important that the items prop passed to SortableContext be sorted in the same order in which the items are rendered, otherwise you may see unexpected results.

It does not expose any callback props. To know when a sortable (draggable) item is being picked or moved over another sortable (droppable) item, use the callback props of DndContext:

import React, {useState} from 'react';
import {DndContext} from '@dnd-kit/core';
import {SortableContext} from '@dnd-kit/sortable';

function App() {
  const [items] = useState(['1', '2', '3']);

  return (
    <DndContext onDragEnd={handleDragEnd}>
      <SortableContext items={items}>
        {/* ... */}
      </SortableContext>
    </DndContext>
  );
  
  function handleDragEnd(event) {
    /* ... */
  }
}

In order for the SortableContext component to function properly, make sure it is a descendant of a DndContext provider. You may nest multiple SortableContext components within the same parent DndContext.

useSortable

As outlined above, the useSortable hook combines both the useDraggable and useDroppable hooks to connect elements as both draggable sources and drop targets:

In most cases, the draggable and droppable hooks will be attached to the same node, and therefore be identical in size. They are represented as different nodes for illustration purposes above.

If you're already familiar with the useDraggable hook, the useSortable hook should look very familiar, since, it is an abstraction on top of it.

In addition to the attributes, listeners,transform and setNodeRef properties, which you should already be familiar with if you've used the useDraggable hook before, you'll notice that the useSortable hook also provides a transition property.

The transform property for useSortable represents the displacement and change of scale transformation that a sortable item needs to apply to transition to its new position without needing to update the DOM order.

The transform property for the useSortable hook behaves similarly to the transform property of the useDraggable hook for the active sortable item, when there is no DragOverlay being used.

SortableItem.jsx

import React from 'react';
import {useSortable} from '@dnd-kit/sortable';
import {CSS} from '@dnd-kit/utilities';

function SortableItem(props) {
  const {
    attributes,
    listeners,
    setNodeRef,
    transform,
    transition,
  } = useSortable({id: props.id});
  
  const style = {
    transform: CSS.Transform.toString(transform),
    transition,
  };
  
  return (
    <div ref={setNodeRef} style={style} {...attributes} {...listeners}>
      {/* ... */}
    </div>
  );
}

The default transition is 250 milliseconds, with an easing function set to ease, but you can customize this and pass any valid CSS transition timing function, or set the transition argument to null to disable transitions entirely:

const {
  transition,
} = useSortable({
  id: props.id,
  transition: {
    duration: 150, // milliseconds
    easing: 'cubic-bezier(0.25, 1, 0.5, 1)',
  },
});

For more details on the useSortable hook, read the full API documentation.

Sensors

Sensors are an abstraction to manage and listen to different input methods. If you're unfamiliar with the concept of sensors, we recommend you read the introduction to sensors first.

By default, the Keyboard sensor moves the active draggable item by 25 pixels in the direction of the arrow key that was pressed. This is an arbitrary default, and can be customized using the coordinateGetter option of the keyboard sensor.

The sortable preset ships with a custom coordinate getter function for the keyboard sensor that moves the active draggable to the closest sortable element in a given direction within the same DndContext.

To use it, import the sortableKeyboardCoordinates coordinate getter function provided by @dnd-kit/sortable, and pass it to the coordiniateGetter option of the Keyboard sensor.

In this example, we'll also be setting up the Pointer sensor, which is the other sensor that is enabled by default on DndContext if none are defined. We use the useSensor and useSensors hooks to initialize the sensors:

import {
  DndContext,
  KeyboardSensor,
  PointerSensor,
  useSensor,
  useSensors,
} from '@dnd-kit/core';
import {
  SortableContext,
  sortableKeyboardCoordinates,
} from '@dnd-kit/sortable';

function App() {
  const [items] = useState(['1', '2', '3']);
  const sensors = useSensors(
    useSensor(PointerSensor),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    })
  );

  return (
    <DndContext sensors={sensors}>
      <SortableContext items={items}>
        {/* ... */}
      </SortableContext>
    </DndContext>
  );
}

If you'd like to use the Mouse and Touch sensors instead of the Pointer sensor, simply initialize those sensors instead:

import {
  DndContext,
  KeyboardSensor,
  MouseSensor,
  TouchSensor,
  useSensor,
  useSensors,
} from '@dnd-kit/core';
import {
  SortableContext,
  sortableKeyboardCoordinates,
} from '@dnd-kit/sortable';

function App() {
  const [items] = useState(['1', '2', '3']);
  const sensors = useSensors(
    useSensor(MouseSensor, {
      // Require the mouse to move by 10 pixels before activating
      activationConstraint: {
        distance: 10,
      },
    }),
    useSensor(TouchSensor, {
      // Press delay of 250ms, with tolerance of 5px of movement
      activationConstraint: {
        delay: 250,
        tolerance: 5,
      },
    }),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    })
  );

  return (
    <DndContext sensors={sensors}>
      <SortableContext items={items}>
        {/* ... */}
      </SortableContext>
    </DndContext>
  );
}

To learn more about sensors, read the in-depth documentation on sensors:

Sensors

Sorting strategies

The supported use cases of the Sortable preset include vertical lists, horizontal lists, grids, and virtualized lists. Because of the wide variety of use cases supported, it would be difficult to write a single strategy to cover all of these different use cases. Instead, the sortable preset exposes a number of different strategies you can use, that are tailored to these various use cases:

• rectSortingStrategy: This is the default value, and is suitable for most use cases. This strategy does not support virtualized lists.

• verticalListSortingStrategy: This strategy is optimized for vertical lists, and supports virtualized lists.

• horizontalListSortingStrategy: This strategy is optimized for horizontal lists, and supports virtualized lists.

• rectSwappingStrategy: Use this strategy to achieve swappable functionality.

Make sure to use the sorting strategy that is the most adapted to the use case you are building for.

Collision detection algorithm

The default collision detection algorithm of DndContext is the rectangle intersection algorithm. While the rectangle intersection strategy is well suited for many use cases, it can be unforgiving, since it requires both the draggable and droppable bounding rectangles to come into direct contact and intersect.

For sortable lists, we recommend using a more forgiving collision detection strategy such as the closest center or closest corners algorithms.

In this example, we'll be using the closest center algorithm:

import {DndContext, closestCenter} from '@dnd-kit/core';
import {SortableContext} from '@dnd-kit/sortable';

function App() {
  const [items] = useState(['1', '2', '3']);

  return (
    <DndContext collisionDetection={closestCenter}>
      <SortableContext items={items}>
        {/* ... */}
      </SortableContext>
    </DndContext>
  );
}

To learn more about collision detection algorithms and when to use one over the other, read our guide on collision detection algorithms:

碰撞检测算法

Connecting all the pieces

First, let's go ahead and render all of our sortable items:

App.jsx

import React, {useState} from 'react';
import {DndContext} from '@dnd-kit/core';
import {SortableContext} from '@dnd-kit/sortable';

import {SortableItem} from './SortableItem';

function App() {
  const [items] = useState(['1', '2', '3']);
  
  return (
    <DndContext>
      <SortableContext items={items}>
        {items.map(id => <SortableItem key={id} id={id} />)}
      </SortableContext>
    </DndContext>
  );
}

SortableItem.jsx

Next, let's wire up the custom sensors for DndContext and add a custom collision detection strategy:

App.jsx

import React, {useState} from 'react';
import {
  DndContext, 
  closestCenter,
  KeyboardSensor,
  PointerSensor,
  useSensor,
  useSensors,
} from '@dnd-kit/core';
import {
  SortableContext,
  sortableKeyboardCoordinates,
} from '@dnd-kit/sortable';


import {SortableItem} from './SortableItem';

function App() {
  const [items] = useState(['1', '2', '3']);
  const sensors = useSensors(
    useSensor(PointerSensor),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    })
  );
  
  return (
    <DndContext sensors={sensors} collisionDetection={closestCenter}>
      <SortableContext items={items}>
        {items.map(id => <SortableItem key={id} id={id} />)}
      </SortableContext>
    </DndContext>
  );
}

SortableItem.jsx

In this example, we'll be building a vertical sortable list, so we will be using the verticalListSortingStrategy sorting strategy:

import React, {useState} from 'react';
import {
  DndContext, 
  closestCenter,
  KeyboardSensor,
  PointerSensor,
  useSensor,
  useSensors,
} from '@dnd-kit/core';
import {
  SortableContext,
  sortableKeyboardCoordinates,
  verticalListSortingStrategy,
} from '@dnd-kit/sortable';

import {SortableItem} from './SortableItem';

function App() {
  const [items] = useState(['1', '2', '3']);
  const sensors = useSensors(
    useSensor(PointerSensor),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    })
  );

  return (
    <DndContext sensors={sensors} collisionDetection={closestCenter}>
      <SortableContext 
        items={items}
        strategy={verticalListSortingStrategy}
      >
        {items.map(id => <SortableItem key={id} id={id} />)}
      </SortableContext>
    </DndContext>
  );
}

Finally, we'll need to set up event handlers on the DndContext provider in order to update the order of the items on drag end.

import React, {useState} from 'react';
import {
  DndContext, 
  closestCenter,
  KeyboardSensor,
  PointerSensor,
  useSensor,
  useSensors,
} from '@dnd-kit/core';
import {
  arrayMove,
  SortableContext,
  sortableKeyboardCoordinates,
  verticalListSortingStrategy,
} from '@dnd-kit/sortable';

import {SortableItem} from './SortableItem';

function App() {
  const [items, setItems] = useState(['1', '2', '3']);
  const sensors = useSensors(
    useSensor(PointerSensor),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    })
  );

  return (
    <DndContext 
      sensors={sensors}
      collisionDetection={closestCenter}
      onDragEnd={handleDragEnd}
    >
      <SortableContext 
        items={items}
        strategy={verticalListSortingStrategy}
      >
        {items.map(id => <SortableItem key={id} id={id} />)}
      </SortableContext>
    </DndContext>
  );
  
  function handleDragEnd(event) {
    const {active, over} = event;
    
    if (active.id !== over.id) {
      setItems((items) => {
        const oldIndex = items.indexOf(active.id);
        const newIndex = items.indexOf(over.id);
        
        return arrayMove(items, oldIndex, newIndex);
      });
    }
  }
}

Drag Overlay

For most sortable lists, we recommend you use a DragOverlay if your sortable list is scrollable or if the contents of the scrollable list are taller than the viewport of the window.

The <DragOverlay> component provides a way to render a draggable overlay that is removed from the normal document flow and is positioned relative to the viewport. The drag overlay also implements drop animations.

A common pitfall when using the DragOverlay component is rendering the same component that calls useSortable inside the DragOverlay. This will lead to unexpected results, since there will be an id collision between the two components both calling useDraggable with the same id, since useSortable is an abstraction on top of useDraggable.

Instead, create a presentational version of your component that you intend on rendering in the drag overlay, and another version that is sortable and renders the presentational component. There are two recommended patterns for this, either using wrapper nodes or ref forwarding.

In this example, we'll use the ref forwarding pattern to avoid introducing wrapper nodes:

App.jsx

import React, {useState} from 'react';
import {
  closestCenter,
  DndContext, 
  DragOverlay,
  KeyboardSensor,
  PointerSensor,
  useSensor,
  useSensors,
} from '@dnd-kit/core';
import {
  arrayMove,
  SortableContext,
  sortableKeyboardCoordinates,
  verticalListSortingStrategy,
} from '@dnd-kit/sortable';

import {SortableItem} from './SortableItem';
import {Item} from './Item';

function App() {
  const [activeId, setActiveId] = useState(null);
  const [items, setItems] = useState(['1', '2', '3']);
  const sensors = useSensors(
    useSensor(PointerSensor),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    })
  );

  return (
    <DndContext 
      sensors={sensors}
      collisionDetection={closestCenter}
      onDragStart={handleDragStart}
      onDragEnd={handleDragEnd}
    >
      <SortableContext 
        items={items}
        strategy={verticalListSortingStrategy}
      >
        {items.map(id => <SortableItem key={id} id={id} />)}
      </SortableContext>
      <DragOverlay>
        {activeId ? <Item id={activeId} /> : null}
      </DragOverlay>
    </DndContext>
  );
  
  function handleDragStart(event) {
    const {active} = event;
    
    setActiveId(active.id);
  }
  
  function handleDragEnd(event) {
    const {active, over} = event;
    
    if (active.id !== over.id) {
      setItems((items) => {
        const oldIndex = items.indexOf(active.id);
        const newIndex = items.indexOf(over.id);
        
        return arrayMove(items, oldIndex, newIndex);
      });
    }
    
    setActiveId(null);
  }
}

SortableItem.jsx

Item.jsx