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    virtual-scroll

    2.1.1 • Public • Published

    virtual-scroll

    A 2kb gzipped low-level library to create custom scrollers with touch and keyboard support. This is heavily inspired by Bartek Drozdz VirtualScroll util. See his article for reference.

    Features

    • Can create multiple instances with different elements as targets
    • Let you do the actual scrolling logic: use CSS Transforms, WebGL animation or anything you like
    • Native arrow keys support and shift/space support mimicking default browser behaviour

    For high-level libraries based off virtual-scroll, check locomotive-scroll or smooth-scrolling.

    Installation

    npm i virtual-scroll -S
    

    Usage & API

    Constructor

    • new VirtualScroll(options)
      • el: the target element for mobile touch events. Defaults to window.
      • mouseMultiplier: General multiplier for all mousewheel (including Firefox). Default to 1.
      • touchMultiplier: Mutiply the touch action by this modifier to make scroll faster than finger movement. Defaults to 2.
      • firefoxMultiplier: Firefox on Windows needs a boost, since scrolling is very slow. Defaults to 15.
      • keyStep: How many pixels to move with each key press. Defaults to 120.
      • preventTouch: If true, automatically call e.preventDefault on touchMove. Defaults to false.
      • unpreventTouchClass: Elements with this class won't preventDefault on touchMove. For instance, useful for a scrolling text inside a VirtualScroll-controled element. Defaults to vs-touchmove-allowed.
      • passive: if used, will use passive events declaration for the wheel and touch listeners. Can be true or false. Defaults to undefined.
      • useKeyboard: if true, allows to use arrows to navigate, and space to jump from one screen. Defaults to true
      • useTouch: if true, uses touch events to simulate scrolling. Defaults to true

    Methods

    • instance.on(callback, context) Listen to the scroll event using the specified callback and optional context.

    • instance.off(callback, context) Remove the listener.

    • instance.destroy() Remove all events and unbind the DOM listeners.

    Events note: Each instance will listen only once to any DOM listener. These listener are enabled/disabled automatically. However, it's a good practice to always call destroy() on your VirtualScroll instance, especially if you are working with a SPA.

    Event

    When a scroll event happens, all the listeners attached with instance.on(callback, context) will get triggered with the following event:

    {
    	x, // total distance scrolled on the x axis
    	y, // total distance scrolled on the y axis
    	deltaX, // distance scrolled since the last event on the x axis
    	deltaY, // distance scrolled since the last event on the y axis
    	originalEvent // the native event triggered by the pointer device or keyboard
    }

    Example

    import VirtualScroll from 'virtual-scroll'
    
    const scroller = new VirtualScroll()
    scroller.on(event => {
    	wrapper.style.transform = `translateY(${event.y}px)`
    })

    License

    MIT.

    Install

    npm i virtual-scroll

    DownloadsWeekly Downloads

    5,324

    Version

    2.1.1

    License

    MIT

    Unpacked Size

    22.5 kB

    Total Files

    8

    Last publish

    Collaborators

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