jackdeadman / use-mouse-drag

A react hook for creating interaction by dragging the mouse e.g., moving elements and drawing boxes

use-mouse-drag

Examples

• Demo
• Sandbox

A react hook for creating interaction by dragging the mouse e.g., moving elements and drawing boxes

Install

npm install --save use-mouse-drag

Basic Usage

const { mousePosition, dragging } = useMouseDrag(element, constraints)

The mousePosition variable changes whenever the mouse moves. The object contains a start attribute and an end attribute indicating the location of the mouse at the start and the end of dragging. The dragging variable indicates whether or not the mouse is currently down. The mousePosition.start is an undefined value when not being dragged, use mousePosition.end to get current mousePosition.

Both the parameters passed into the hook are optional, The element parameter is the element that will listen for drags and will default to the entire page. The constraints parameter is an array of functions, the function gets passed a mousePosition and if any of the functions are false a drag will not begin.

See the Example below to see how it all fits together.

Example

import React, { useRef, useCallback, useState, useEffect } from 'react'
import { useMouseDrag, useChange } from 'use-mouse-drag'

const App = () => {
  const [ allowDragging, setAllowDragging ] = useState(true);
  const canvasRef = useRef();
  const allowDraggingRef = useRef(allowDragging);

  const { mousePosition, dragging } = useMouseDrag(canvasRef.current, [
    mousePosition => allowDraggingRef.current
  ]);

  useEffect(() => {
    allowDraggingRef.current = allowDragging;
  }, [ allowDragging ]);

  useChange(() => {
    // Drag ended
    if (!dragging) {
      alert('Dragged: ' + JSON.stringify(mousePosition))
    }
  }, [ dragging ]);

  return (
    <React.Fragment>
      <div ref={canvasRef} className="canvas"
      style={
        { opacity: allowDragging ? 1: 0.4 }
      }>
      </div>

      <div>Dragging: { dragging.toString() }</div>
      <div>Position: { JSON.stringify(mousePosition) }</div>
      <button onClick={() => setAllowDragging(!allowDragging)}>
        Turn dragging { allowDragging ? 'Off' : 'On' }
      </button>
    </React.Fragment>
  )
}
export default App

License

MIT © jackdeadman

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This hook is created using create-react-hook.