scrollbooster

ScrollBooster

Enjoyable content drag-to-scroll micro (~2KB gzipped) library.

Installation

You can install it via npm package manager or just drop a script tag:

npm i scrollbooster

<script src="https://unpkg.com/scrollbooster@1.0.3/dist/scrollbooster.min.js"></script>

Usage

import ScrollBooster from 'scrollbooster'

let sb = new ScrollBooster({
  viewport: document.querySelector('.viewport') // required
  // ...other options
})

Options

Option	Type	Default	Description
viewport	element	null	Viewport - outer element
content	element	First child of viewport element	Scrollable content inside viewport
handle	element	Viewport element	Element that respond to drag event
bounce	boolean	true	Inertia bounce effect (scroll past viewport borders)
friction	float	0.05	Scroll friction factor (scroll inertia after pointer release)
bounceForce	float	0.1	Bounce effect factor
emulateScroll	boolean	false	Emulate viewport mouse wheel events (for cases when scrolling with transform property)
onUpdate	function	noop	User function that updates element properties according to received coordinates (see demo examples). Receives object with properties: position, viewport and content. Each property contains metrics to perform an actual scrolling

Methods

Method	Description
setPosition	Sets new scroll position in viewport. Receives an object with properties x and y
updateMetrics	Updates element sizes. Useful for images loading or other dynamic content
getUpdate	Returns current metrics and coordinates in a same format as onUpdate
destroy	Destroys all instance's event listeners

Full Example

let viewport = document.querySelector('.viewport')
let content = document.querySelector('.viewport-content')

let sb = new ScrollBooster({
  viewport: viewport,
  content: content,
  handle: document.querySelector('.viewport-scroller'), 
  bounce: true,
  emulateScroll: false,
  onUpdate: (data)=> {
    content.style.transform = `translate(
      ${-data.position.x}px,
      ${-data.position.y}px
    )`
    // and also metrics: data.viewport['width'|'height'] and data.cotent['width'|'height']
  }
})

// methods example:
sb.updateMetrics()
sb.setPosition({
  x: 100,
  y: 100
})
sb.destroy()

Browser support

ScrollBooster has been tested in IE 11, Edge and other modern browsers (Chrome, Firefox, Safari).

Special thanks

David DeSandro for his talk "Practical UI Physics".

License

MIT License (c) Ilya Shubin