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This software is maintained under a new repository located at yowainwright/stickybits

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StickyBits banner

Make things get sticky …in a good way

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StickyBits 🍬

Stickybits is a lightweight alternative to position: sticky polyfills. It works perfectly for things like sticky headers.

Stickybits is awesome because

  • it can add a CSS Sticky Class (.js-is-sticky) when position: sticky elements become active and a CSS Stuck Class (.js-is-stuck) when they become stuck. See useStickyClasses.
  • it loosely mimics position: sticky to consistently stick elements vertically across multiple platforms
  • it does not have the jumpiness that plugins that are built around position: fixed have because it tries to support position: sticky first.
  • in its simplest use case, a scroll event listener will not be used if position: sticky is supported.
  • it is super simple & lightweight
  • it provides a wiki that digs deeply into fundementals of position: sticky and position: fixed and it works with them.

Installation   Setup   Usage   Feature   Options   Examples   Debugging   Notes   Contributing   Wiki

Installing from a package manager

yarn

yarn add stickybits

npm

npm i stickybits

Setup

Add dist/stickybits.min.js

Or as a module with import stickybits from 'stickybits'

Basic Usage

stickybits('selector');

By default, a selected stickybits element will

  • Stick elements to the top of the viewport when scrolled to vertically.
  • Stick elements at the bottom of their parent element when scrolled past.

Key Note: Stickybits expects and works best when the element that will become sticky is wrapped within a parent element that defines when the element starts being sticky and stops being sticky. See below for visual reference.

<main id="some-stickybit-parent">
  <nav id="some-stickybit-nav"></nav>
</main>

useStickyClasses Feature

Stickybits allows customers to add CSS to elements when they become sticky and when they become stuck at the bottom of their parent element.

By default, if position: sticky is supported, StickyBits will exit allowing the browser to manage stickiness and avoid adding a scroll event listener.

If the useStickyClasses argument is set to true then even if a browser supports position: sticky, StickyBits will still add a scroll event listener to add and remove sticky CSS Classes. This option is available so that CSS styles can use when StickyBits elements become sticky or stuck at the bottom of their parent.

To provide more feature richness to the Stickybits experience, a .js-is-sticky--change CSS class is added after the Stickybit element is sticky for a certain duration of scroll. By default this duration of scrolling is the height of the Stickybit element. The scroll duration for when .js-is-sticky--change is added can be modified by providing a number for customStickyChangeNumber option.

To use useStickyClasses:

stickybits('selector', {useStickyClasses: true});

Then, in css you can do:

.some-sticky-element.js-is-sticky {
  background-color: red;
}
.some-sticky-element.js-is-sticky--change {
  height: 50px;
}
.some-sticky-element.js-is-stuck {
  background-color: green;
}

View add css classes for more information on StickyBits CSS Classes.

Options

Vertical Layout Position

By default, a StickyBits element will stick to the top of the viewport when vertically scrolled to.

Stickybits loosely works for bottom positioning as well.

To have a StickyBits element stick to the bottom:

stickybits('selector', {verticalPosition: 'bottom'});

Custom Scroll Element

By default, if Stickybits uses window scrolling to define Sticky Elements. An element besides window can be used if window is undefined by selecting the desired scrolling element with the scrollEl option. For more custom sticky featuring, the scrollEl option can be used. However, those implementations require the implementing developers support.

To have Stickybit use an selector besides window:

stickybits('selector', {scrollEl: 'an-id'});

StickyBit Sticky Offset

By default, a StickyBits element will have a 0px sticky layout top offset. This means that the element will stick flush to the top of the viewport.

To have a StickyBits element stick with a 20px offset to its vertical layout position:

stickybits('selector', {stickyBitStickyOffset: 20});

StickyBits Cleanup

To cleanup an instance of Stickybits:

const stickybitsInstancetoBeCleanedup = stickybits('selector');
stickybitsInstancetoBeCleanedup.cleanup();

StickyBits Update

To update the calculations of an instance of Stickybits:

const stickybitsInstancetoBeUpdated = stickybits('selector');
stickybitsInstancetoBeUpdated.update();

Re-calculates each Stickybits instance's offsets (stickyStart, stickyStop). If the Stickybits implementer would like re-calculate offsets when the DOM window is resized or when the url changes. .update() can be invoked within an event listener.

const stickybitsInstancetoBeUpdated = stickybits('selector');
stickybitsInstancetoBeUpdated.update({ stickyBitStickyOffset: 20 });

More Stickybits Update Examples

// when the window is resized
const stickybitsInstancetoBeUpdated = stickybits('selector');
window.addEventListener('resize', () => {
  stickybitsInstancetoBeUpdated.update();
});
// when the url hash changes
window.addEventListener('hashchange', () => {
  stickybitsInstancetoBeUpdated.update();
});

Note: .update does not re-initialize classnames or pre-set calculations. Perhaps the update value can help you with that (see the paragraph below).

StickBits Update Props

Props can be updated to each instance by passing then into the .update function as an object.

// .update({ someProp: somePropValue })
const stickybitsInstancetoBeUpdated = stickybits('selector');
stickybitsInstancetoBeUpdated.update({ stickyBitStickyOffset: 20 });

StickyBits NoStyles

To use StickyBits without inline styles except for position: sticky or position: fixed:

stickybits('selector', {noStyles: true});

StickyBits Custom CSS Classes

To use custom CSS classes for Stickybits, add the appropriate properties and values.

parentClass:

stickybits('selector', {parentClass: 'new-parent-classname'});

stickyClass:

stickybits('selector', {stickyClass: 'new-sticky-classname'});

stuckClass:

stickybits('selector', {stuckClass: 'new-stuck-classname'});

StickyBits useFixed

To not use position: sticky ever, add the following key value to a stickybit initalization.

parentClass:

stickybits('selector', {useFixed: true});

To change all of the CSS classes

stickybits('selector', {
  parentClass: 'new-parent-classname',
  stickyClass: 'new-sticky-classname',
  stuckClass: 'new-stuck-classname',
  stickyChangeClass: 'new-sticky-change-classname'
});

StickyBits useGetBoundingClientRect

To not use offsetTop provide the optional boolean useGetBoundingClientRect. This feature is optimal when dealing with things like CSS calc which can throw off offsetTop calculations. Read more about this functionality here.

stickybits('selector', {useGetBoundingClientRect: true});

* For jQuery and Zepto support, read the jQuery notes below.

StickyBits applyStyle

If you want to take control of how styles and classes are applied to elements provide a function applyStyle. This is useful for example if you want to integrate with a framework or view library and want to delegate DOM manipulations to it.

stickybits('selector', {
  applyStyle: ({ classes, styles }, instance) => {
    // Apply styles and classes to your element
  }
});

Examples

Extended Examples

Have another example or question? Feel free to comment. 🙌

Notes

CSS Class Usage

3 CSS classes will be added and removed by Stickybits if position: sticky is not supported or if the useStickyClasses: true option is added to the plugin call. These Classes can be modified as desired. See the With Custom Classes example above.

  • js-is-sticky if the selected element is sticky.
  • js-is-stuck if the selected element is stopped at the bottom of its parent.
  • js-stickybit-parent so that styles can easily be added to the parent of a Stickybits element

Not a Polyfill

Stickybits is not a Shim or Polyfill for position: sticky because full support would require more code. This plugin makes elements vertically sticky very similarly to position: fixed but in a sticky sort of way. Read more about position sticky here or follow its browser implementation here.

Stickybits is a no dependency JavaScript plugin. It provides the smallest API possible in both features and kb size to deliver working sticky elements. This means that opinionated featuring is left out as much as possible and that it works with minimal effort in Frameworks.

CSS when position: sticky is not supported

Sticky Start and Sticky Stop: Because Stickybits is minimal, when position: sticky is not supported Stickybits will use position: fixed which is relative to the browser window. If the StickyBits parent element has a height recognized by the browser, Stickybits will take care of the sticky top and sticky bottom invocation. If the parent's height is not recognized by the browser there will be issues.

Left and Right Positioning: With position: fixed the Stickybit element will work relative to the browser window by default. To work with this issue, there are several options. Some are noted here. More solutions to come!

jQuery and Zepto Usage

Basic

$('selector').stickybits();

With scrollEl

$('selector').stickybits({scrollEl: '#scrollEl'});

// or

const el = document.querySelector('#scrollEl');
$('selector').stickybits({scrollEl: el});

With .update

const  instance = $('selector').stickybits();
instance.update();

With useStickyClasses

$('selector').stickybits({useStickyClasses: true});

With verticalPosition

$('selector').stickybits({verticalPosition: 'bottom'});

With stickyBitStickyOffset

$('selector').stickybits({stickyBitStickyOffset: 20});

Debugging

Stickybits 2.0 provides the same API but with more debugging feedback.

To view the Stickybits API in it's simpliest form:

const  stickybit = stickybits('a selection');
console.log(stickybit);

For more debugging and managing Stickybits, view the wiki.

Utility properties

Stickybits provides both version and userAgent properties which were added to offer insight into the browser and Stickybits.

These utility properties can be accessed as direct child properties of the instantiated Stickybits item.

const stickybit = stickybits('a selection')
stickybit.version // will show the version of stickybits being used
stickybit.userAgent // will show which userAgent stickybits is detecting

Browser Compatibility

Stickybits works in all modern browsers including Internet Explorer 9 and above. Please file and issue with browser compatibility quirks.

Contributing

Please contribute to Stickybits by filing an issue, responding to issues, adding to the wiki, or reaching out socially—etc.

Stickybits is a utility. It may often not be needed! With shared understanding of position: sticky and position: fixed along with product awareness, Stickybits can improve as can a shared understanding of the "sticky element issue". Is this paragraph over-reaching? Yes! Help improve it.

Thanks

This plugin was heavily influenced by Filament Group's awesome Fixed-sticky jQuery plugin. Thanks to them for getting my mind going on this a while back. Thanks to Peloton Cycle's Frame Throttle for an insightful solve for optimizing frame throttling.

Architecture discussions and Pull Request help has been provided by Jacob Kelley, Brian Gonzalez, and Matt Young. It is much appreciated!

Created and maintained by Jeff Wainwright with Dollar Shave Club Engineering.

More great contributors