content-scroll-tracker

About

Widget is used to track & display user scrolled content percentage.

Usualy it's just a top bar :)

Install

npm install content-scroll-tracker

Usage

Initialize your tracker component like:

// your imports
import ContentScrollTracker from 'content-scroll-tracker';
// ... some code maybe...
const scrollTracker = new ContentScrollTracker('#tracker', 'width');
// ... and other additional props can be applyed to component (more about it in Props section) ...
// ... Also feel free to checkout example inside of a package (example/index.html & exm/example.js) ...

Props

Property	Meaning	Example	Required
selector	Selector of tracker instance in HTML	#tracker	- [x]
behaviour	Defines what property of tracker should change on scroll (width or height can be accepted)	width	- [x]
scrollColors	JSON object witch consists of percentage number of scrolled length & color which should be appled	{0: "red", 25: "rgb(0, 0, 0)", 50: "rgba(0, 0, 0, 0.5)", 75: #ff0000, 100: "green"}	- []
trackHeadingsItemSelector	Selector for additional component to display section name on scroll	#tracker--section	- []
trackHeadingsSelector	Selector for elements (usaly h$ (headers)) to track on which section is currently scrolled on	.tracker--heading	- []
headingChangeEvent	Function, which is executed when content of section header will change. (item represents header tracking DOM; event(fn) represents function, which will change headings tracking DOM content to the next one and if some function is passed to it, after the change it will be executed.)	(item, event) => {}	- []
hideOnScrolledToTop	Hides heading tracking element, when user scrolls to top	true/false	- []

Examples

Simple scroll tracker with changing background

    <!-- -->
    <div class="tracker" id="tracker"></div>
    <!-- -->

    import ContentScrollTracker from 'content-scroll-tracker';
    // ...
    const st = new ContentScrollTracker('#tracker', 'width', {
        0: "red",
        10: "green",
        20: "blue",
        30: "rgb(255, 0, 0)",
        40: "rgb(0, 255, 0)",
        50: "rgb(0, 0, 255)",
        60: "rgb(0, 0, 255, 0.5)",
        70: "rgb(0, 0, 255, 0)",
        80: "#ff0000",
        90: "#00ff00",
        100: "#0000ff",
    });
    // ...

Scroll tracker with heading tracking element

    <!-- -->
    <div class="tracker" id="tracker"></div>
    <div class="tracker--section" id="tracker--section"></div>
    <div>
        <h1 class="tracker--heading">Heading1</h1>
        <h1 class="tracker--heading">Heading2</h1>
        <h1 class="tracker--heading">Heading3</h1>
        <h1 class="tracker--heading">Heading4</h1>
        <h1 class="tracker--heading">Heading5</h1>
    </div>
    <!-- -->

    import ContentScrollTracker from 'content-scroll-tracker';
    // ...
    // '#tracker--section' is a div selector, which content will be changed by h2 DOM content when user scrolls on it
    // '.tracking--heading' is a DOM elements selector
    const st = new ContentScrollTracker('#tracker', {}, '#tracker--section',  '.tracker--heading');
 
    // Also if you want to add some animating through CSS classes
    // (or as in this particular case JS)
    // you can append 'OnChange' event function on which you can:
    // * do something before content change.
    // * trigger change event (which will change content).
    //   - on triggering, you can pass function, which will be executed after content change.
    const st = new ContentScrollTracker('#tracker', 'width', {
        0: "red",
        10: "green",
        20: "blue",
        30: "rgb(255, 0, 0)",
        40: "rgb(0, 255, 0)",
        50: "rgb(0, 0, 255)",
        60: "rgb(0, 0, 255, 0.5)",
        70: "rgb(0, 0, 255, 0)",
        80: "#ff0000",
        90: "#00ff00",
        100: "#0000ff",
    }, '#tracker--section', '.tracker--heading', (item, event) => {
        // before change...
        item.style.left = '-150px';
        item.style.opacity = 0;
        setTimeout(() => {
            // triggering change event...
            event(() => {
                // post change event...
                item.style.left = '15px';
                item.style.opacity = 1;
            });
        }, 150);
    }, true);
    // boolean on end of constructor is a notation to hide heading tracker DOM when user reaches very top of first section or above it.

Styling of tracker bar

All styling depends on you how it will be presented, where & etc.