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scrollbooster

3.0.2 • Public • Published

ScrollBooster

Enjoyable drag-to-scroll micro library (~2KB gzipped). Supports smooth content scroll via mouse/touch dragging, trackpad or mouse wheel. Zero dependencies.

Easy to setup yet flexible enough to support any custom scrolling logic.

Installation

You can install it via npm or yarn package manager or via script tag:

npm i scrollbooster
yarn add scrollbooster
<script src="https://unpkg.com/scrollbooster@2/dist/scrollbooster.min.js"></script>

Usage

The most simple setup with default settings:

import ScrollBooster from 'scrollbooster';
 
new ScrollBooster({
    viewport: document.querySelector('.viewport'),
    scrollMode: 'transform'
});

Please note that in order to support IE11 you should replace arrow functions and string templates from code examples to supported equivalents or just use Babel.

Options

Option Type Default Description
viewport DOM Node null Content viewport element (required)
content DOM Node viewport child element Scrollable content element inside viewport
scrollMode String undefined Scroll technique - via CSS transform or natively. Could be 'transform' or 'native'
direction String 'all' Scroll direction. Could be 'horizontal', 'vertical' or 'all'
bounce Boolean true Enables elastic bounce effect when hitting viewport borders
textSelection Boolean false Enables text selection inside viewport
inputsFocus Boolean true Enables focus for elements: 'input', 'textarea', 'button', 'select' and 'label'
pointerMode String 'all' Specify pointer type. Supported values - 'touch' (scroll only on touch devices), 'mouse' (scroll only on desktop), 'all' (mobile and desktop)
friction Number 0.05 Scroll friction factor - how fast scrolling stops after pointer release
bounceForce Number 0.1 Elastic bounce effect factor
emulateScroll Boolean false Enables mouse wheel/trackpad emulation inside viewport
preventDefaultOnEmulateScroll String false Prevents horizontal or vertical default when emulateScroll is enabled (eg. useful to prevent horizontal trackpad gestures while enabling vertical scrolling). Could be 'horizontal' or 'vertical'.
lockScrollOnDragDirection String false Detect drag direction and either prevent default mousedown/touchstart event or lock content scroll. Could be 'horizontal', 'vertical' or 'all'
dragDirectionTolerance Number 40 Tolerance for horizontal or vertical drag detection
onUpdate Function noop Handler function to perform actual scrolling. Receives scrolling state object with coordinates
onClick Function noop Click handler function. Here you can, for example, prevent default event for click on links. Receives object with scrolling metrics and event object. Calls after each click in scrollable area
onPointerDown Function noop mousedown/touchstart events handler
onPointerUp Function noop mouseup/touchend events handler
onPointerMove Function noop mousemove/touchmove events handler
onWheel Function noop wheel event handler
shouldScroll Function noop Function to permit or disable scrolling. Receives object with scrolling state and event object. Calls on pointerdown (mousedown, touchstart) in scrollable area. You can return true or false to enable or disable scrolling

List of methods

Method Description
setPosition Sets new scroll position in viewport. Receives an object with properties x and y
scrollTo Smooth scroll to position in viewport. Receives an object with properties x and y
updateMetrics Forces to recalculate elements metrics. Useful for cases when content in scrollable area change its size dynamically
updateOptions Sets option value. All properties from Options config object are supported
getState Returns current scroll state in a same format as onUpdate
destroy Removes all instance's event listeners

Full Example

const viewport = document.querySelector('.viewport');
const content = document.querySelector('.scrollable-content');
 
const sb = new ScrollBooster({
  viewport,
  content,
  bounce: true,
  textSelection: false,
  emulateScroll: true,
  onUpdate: (state) => {
    // state contains useful metrics: position, dragOffset, dragAngle, isDragging, isMoving, borderCollision
    // you can control scroll rendering manually without 'scrollMethod' option:
    content.style.transform = `translate(
      ${-state.position.x}px,
      ${-state.position.y}px
    )`;
  },
  shouldScroll: (state, event) => {
    // disable scroll if clicked on button
    const isButton = event.target.nodeName.toLowerCase() === 'button';
    return !isButton;
  },
  onClick: (state, event, isTouchDevice) => {
    // prevent default link event
    const isLink = event.target.nodeName.toLowerCase() === 'link';
    if (isLink) {
      event.preventDefault();
    }
  }
});
 
// methods usage examples:
sb.updateMetrics();
sb.scrollTo({ x: 100, y: 100 });
sb.updateOptions({ emulateScroll: false });
sb.destroy();

Live ScrollBooster Examples On CodeSandbox

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

Install

npm i scrollbooster

DownloadsWeekly Downloads

1,960

Version

3.0.2

License

MIT

Unpacked Size

120 kB

Total Files

21

Last publish

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