🥨 Snap Slider

Simple JavaScript plugin to manage sliders using CSS Scroll Snap.

⚡️ Quick Start

npm install @tannerhodges/snap-slider
import SnapSlider from '@tannerhodges/snap-slider'; -- OR -- <script async src="snap-slider.min.js"></script>
Add data-snap-slider to your elements.

📖 Outline

Why?
Install
HTML API
JavaScript API
CodePen Examples
Changelog

🤔 Why?

CSS Scroll Snap makes sliders as simple as a few lines of CSS, but you still need JavaScript for things like buttons and event handlers.

Snap Slider makes that as easy as adding a data-snap-slider attribute.

👉 For a full explanation & demos, check out the docs.

⚙️ Install

Install the package.

npm install @tannerhodges/snap-slider

Import the package into your application script.

import SnapSlider from '@tannerhodges/snap-slider';

Or, if you prefer, include the script in your HTML.

<script async src="snap-slider.min.js"></script>

Add data attributes to your CSS sliders.

<ul class="slider" data-snap-slider="example">
  <li class="slide">...</li>
  <li class="slide">...</li>
  <li class="slide">...</li>
  <li class="slide">...</li>
</ul>

<ul class="slider-nav" data-snap-slider-nav="example">
  <li><button type="button">Previous</button></li>
  <li><button type="button">1</button></li>
  <li><button type="button">2</button></li>
  <li><button type="button">3</button></li>
  <li><button type="button">4</button></li>
  <li><button type="button">Next</button></li>
</ul>

👨‍🏫 HTML API

Elements

data-snap-slider="<ID>" - Container. Create a slider for this container element. Should have CSS position: relative, overflow: scroll, and scroll-snap-type defined.
data-snap-slider-nav="<ID>" - Nav. Wrap around a group of buttons to specify which slider they control.
data-snap-slider-goto="<SLIDE>" - "Goto" Button. Tell a button which slide it should go to. (Can target specific sliders using <ID>:<SLIDE> syntax.)
- Possible values: Numbers (starting at 1), first, middle, last, prev, next.

Options

data-snap-slider-slides - By default, Snap Slider assumes all the container's children are slides. If you have non-slide elements in your slider, add this attribute to the container to specify which elements should be treated as slides.
data-snap-slider-align="<ALIGN>" - Snap Slider checks each slide's CSS scroll-snap-align to calculate its scroll position, but older browsers fail to return this value. If you need to support center or end alignments in Internet Explorer, add this attribute to a container or slide to specify its alignment.
- Possible values: start, end, or center.
data-snap-slider-start="<SLIDE>" - Sliders start on slide 1 by default. Add this attribute to a container to specify a different slide to start on.
- Possible values: Numbers (starting at 1), first, middle, last.
data-snap-slider-loop="<BOOLEAN>" - Previous/next buttons are disabled on the first/last slides by default. Add this attribute to a container to enable them to loop around to the other end of the slider (e.g., clicking a previous button on slide 1 will goto the last slide).
data-snap-slider-buttons="<SELECTOR>" - Snap Slider automatically inits buttons in nav elements as goto buttons. Add this attribute to a container or nav to specify which elements should be treated as goto buttons.
data-snap-slider-prev="<SELECTOR>" - Snap Slider tries to detect previous buttons based on their content and class names (e.g., if the text or class contains the string "prev"). Add this attribute to a container or nav to target a custom selector for previous buttons.
data-snap-slider-next="<SELECTOR>" - Snap Slider tries to detect next buttons based on their content and class names (e.g., if the text or class contains the string "next"). Add this attribute to a container or nav to target a custom selector for next buttons.

🤖 JavaScript API

Constructor

const slider = new SnapSlider(
  // `container` - This is the slider's container element.
  // You can pass in a string selector, Element, NodeList, or jQuery object.
  container,

  // `options` - This object extends the default settings.
  {
    // `options.id` - String ID for this slider.
    //   Use this to associate containers, navs, and goto buttons.
    //   If empty, defaults to `container.children`.
    id: '',

    // `options.slides` - String selector to target slide elements.
    //   Useful if you have non-slide elements in your container.
    //   If empty, defaults to `container.children`.
    slides: '',

    // `options.align` - String to specify fallback alignment for older browsers.
    //   Mimics `scroll-snap-align` for browsers that don't support CSS Scroll Snap.
    align: '',

    // `options.nav` - String selector to target nav elements.
    //   Looks for matches across the whole document.
    nav: '',

    // `options.buttons` - String selector to target goto buttons.
    //   Looks for matches in container and nav elements.
    buttons: '',

    // `options.prev` - String selector to target previous buttons.
    //   Looks for matches in container and nav elements.
    prev: '',

    // `options.next` - String selector to target next buttons.
    //   Looks for matches in container and nav elements.
    next: '',

    // `options.start` - Number or string alias to change which slide is current on load.
    //   Accepts any valid goto alias (numbers starting at 1, `first`, `middle`, `last`).
    start: 1,

    // `options.loop` - Boolean to enable prev/next buttons to loop around to the other end of the slider.
    loop: false,

    // `options.on` - Object to add callbacks for different events.
    on: {
      'load': () => {},
      'change': () => {},
      'change.click': () => {},
      'change.scroll': () => {},
      'change.keydown': () => {},
      'change.focusin': () => {},
      'scroll': () => {},
      'scroll.start': () => {},
      'scroll.end': () => {},
    },
  }
);

Properties

align - What's this slider's CSS scroll-snap-align?
callbacks - Functions to fire for each slider event.
container - Container element.
current - Index of current slide. Values start at 1.
id - Slider ID.
loop - Boolean. Should slide loop or not?
options - Slider options (default values + custom overrides).
scrolling - Boolean. Is the slider scrolling at this moment?
slides - Array of slides.
transition - Object. Are we in the middle of a transition? Where from, to, etc.?

Instance Methods

getSlide(index) - Get a specific slide element. Accepts any valid goto alias.
getCurrentSlide() - Get the current slide element.
goto(index, [options]) - Go to a slide.
- Goto Aliases - Numbers (starting at 1), first, middle, last, prev, next.
- options.focus - By default, we focus slides when you go to them (except for relative changes like prev and next). Use this option to disable the default focus handling.
- options.force - Force-update the scroll position, even if we're already on the current slide.
- options.ignoreCallbacks - Ignore custom callbacks for events.
- options.immediate - Immediately update position without smooth scrolling.
addNav(containerOrOptions, [options]) - Add a nav element for the current slider. Automatically hooks up any nav buttons inside the nav.
- options.container - The nav element. Defaults to containerOrOptions. Limits the query for buttons, prev, and next to be inside the nav container (instead of the whole document).
- options.buttons - String selector to target goto buttons inside the nav container. If empty, defaults to button.
- options.prev - String selector to target previous buttons inside the nav container.
- options.next - String selector to target next buttons inside the nav container.
addGotoButtons(buttonsOrOptions, [options]) - Add goto buttons for the current slider.
- options.container - A parent nav element. If set, limits the query for buttons, prev, and next to be inside the nav container (instead of the whole document).
- options.buttons - String selector to target goto buttons. Defaults to buttonsOrOptions.
- options.prev - String selector to target previous buttons.
- options.next - String selector to target next buttons.
update() - Update this slider (e.g., on resize). Basically just repositions the current slide.
reset() - Reset this slider (e.g., after adding or removing a slide). Updates the slide elements, our internal slides array, and repositions the current slide.
destroy() - Destroy this slider. Stop any active transitions, remove its event listeners, and delete it from our internal array of slider instances.
on(event, callback) - Add callbacks to fire on specific events.
- change - Fires any time the current slide changes.
- change.click - Fires when a user clicks a goto button.
- change.scroll - Fires when a user scrolls to another slide.
- change.keydown - Fires when a user is focused inside the container and presses an arrow key to change the current slide (e.g., up, down, left, or right).
- change.focusin - Fires when a slide gains focus.
  - Note: For keyboard accessibility, we automatically focus the target slide whenever a user clicks a non-relative goto button. In other words, if you goto any index besides prev or next we'll auto-focus that slide.

Static Methods

SnapSlider.get(id) - Get the SnapSlider object for a slider based on its ID.
SnapSlider.debug([idOrElements]) - console.log info about a slider, its nav, or goto buttons.

HTML Properties

Element.SnapSlider - After a slider is intialized, you can access its SnapSlider instance by getting the element's SnapSlider property. For example, document.querySelector('.example').SnapSlider.

Example

import SnapSlider from '@tannerhodges/snap-slider';

// Create a new slider.
const slider = new SnapSlider('.example', {
  id: 'example-slider',
  nav: '.example-nav',
  start: 'middle',
});

// The rest is up to you!
// 🏃‍♂️ Go make something!

✍️ CodePen Examples

TODO: Examples

tannerhodges/snap-slider