React drag-to-select

A highly-performant React library which adds drag-to-select to your app.

✨ Features

• Near 60 fps in 6x CPU slowdown on 2.3 GHz Quad-Core Intel Core i7
• Simple API. It doesn't actually select items; just draws the selection box and passes you coordinates so you can determine that (we provided a utility to help though)
• Fully built in TypeScript
• Unit and e2e tested
• Actively battle-tested in a production-scale application

Install

npm install --save @air/react-drag-to-select

yarn add @air/react-drag-to-select

Usage

import { useSelectionContainer } from '@air/react-drag-to-select'

const App = () => {
  const { DragSelection } = useSelectionContainer();

  return (
    <div>
      <DragSelection/>
      <div>Selectable element</div>
    </div>
  )
}

Check out this codesandbox for a complete working example: https://codesandbox.io/s/billowing-lake-rzhid4

useSelectionContainer arguments

Name	Required	Type	Default	Description
onSelectionStart	No	() => void		Method called when selection starts (mouse is down and moved)
onSelectionEnd	No	() => void		Method called when selection ends (mouse is up)
onSelectionChange	Yes	(box: Box) => void		Method called when selection moves
isEnabled	No	boolean	true	If false, selection does not fire
eventsElement	No	Window, HTMLElement or null	window	Element to listen mouse events
selectionProps	No	React.HTMLAttributes		Props of selection - you can pass style here as shown below
shouldStartSelecting	No	() => boolean	undefined	If supplied, this callback is fired on mousedown and can be used to prevent selection from starting. This is useful when you want to prevent certain areas of your application from being able to be selected. Returning true will enable selection and returning false will prevent selection from starting.

Selection styling

To style the selection box, pass selectionProps: { style } prop:

  const { DragSelection } = useSelectionContainer({
    ...,
    selectionProps: {
      style: {
        border: '2px dashed purple',
        borderRadius: 4,
        backgroundColor: 'brown',
        opacity: 0.5,
      },
    },
  });

The default style for the selection box is

{
  border: '1px solid #4C85D8',
  background: 'rgba(155, 193, 239, 0.4)',
  position: `absolute`,
  zIndex: 99,
}

Disabling selecting in certain areas

Sometimes you want to disable a user being able to start selecting in a certain area. You can use the shouldStartSelecting prop for this.

const { DragSelection } = useSelectionContainer({
  shouldStartSelecting: (target) => {
    /**
     * In this example, we're preventing users from selecting in elements
     * that have a data-disableselect attribute on them or one of their parents
     */
    if (target instanceof HTMLElement) {
      let el = target;
      while (el.parentElement && !el.dataset.disableselect) {
        el = el.parentElement;
      }
      return el.dataset.disableselect !== "true";
    }

    /**
    * If the target doesn't exist, return false
    * This would most likely not happen. It's really a TS safety check
    */
    return false;
  }
});

See full example here: https://codesandbox.io/s/exciting-rubin-xxf6r0

Scrolling

Because we use the mouse position to calculate the selection box's coordinates, if your <DragSelection /> is inside of an area that scrolls, you'll need to make some adjustments on your end. Our library can't inherently know which parent is being scrolled nor of it's position inside of the scrolling parent (if there are other sibling elements above it).

How this is solved on your end is modifiying the left (for horizontal scrolling) and top (for vertical scrolling) of the selectionBox that is passed to handleSelectionChange. See the onSelectionChange in the example for an idea of how to do this.