Резиновый ползунок или range slider

Range slider с эффектом резиновости реализованном с помощью gsap tweenmax.

HTML

<div class="box">
    <h3>Price <span>Range</span></h3>
    <div class="values">
        <div>$<span id="first"></span></div> - <div>$<span id="second"></span></div>
    </div>
    <small>
        Current Range:
        <div>$<span id="third"></span></div>
    </small>
    <div class="slider" data-value-0="#first" data-value-1="#second" data-range="#third"></div>
</div>

SCSS

body {
    &.ui-slider-active {
        cursor: grabbing;
    }
}

.box {
    --primary: #275efe;
    --headline: #3F4656;
    --text: #99A3BA;
    width: 100%;
    max-width: 312px;
    padding: 36px 32px 48px 32px;
    background: #fff;
    border-radius: 9px;
    box-shadow: 0 1px 4px rgba(18, 22, 33, .12);
    h3 {
        font-family: inherit;
        font-size: 32px;
        font-weight: 700;
        margin: 0 0 20px 0;
        color: var(--headline);
        span {
            font-weight: 500;
        }
    }
    .values,
    small {
        div {
            display: inline-block;
            vertical-align: top;
        }
    }
    .values {
        margin: 0;
        font-weight: 500;
        color: var(--primary);
        & > div {
            &:first-child {
                margin-right: 2px;
            }
            &:last-child {
                margin-left: 2px;
            }
        }
    }
    small {
        color: var(--text);
        display: block;
        margin-top: 8px;
        font-size: 14px;
    }
    .slider {
        margin-top: 40px;
    }
}

.slider {
    --primary: #275efe;
    --handle: #fff;
    --handle-active: #{mix(white, #275efe, 70%)};
    --handle-hover: #{mix(white, #275efe, 90%)};
    --handle-border: 2px solid var(--primary);
    --line: #cdd9ed;
    --line-active: var(--primary);
    height: 23px;
    width: 100%;
    position: relative;
    pointer-events: none;
    .ui-slider-handle {
        --y: 0;
        --background: var(--handle);
        cursor: grab;
        -webkit-tap-highlight-color: transparent;
        top: 0;
        width: 23px;
        height: 23px;
        transform: translateX(-50%);
        position: absolute;
        outline: none;
        display: block;
        pointer-events: auto;
        div {
            width: 23px;
            height: 23px;
            border-radius: 50%;
            transition: background .4s ease;
            transform: translateY(calc(var(--y) * 1px));
            border: var(--handle-border);
            background: var(--background);
        }
        &:hover {
            --background: var(--handle-hover);
        }
        &:active {
            --background: var(--handle-active);
            cursor: grabbing;
        }
    }
    svg {
        --stroke: var(--line);
        display: block;
        height: 83px;
        path {
            fill: none;
            stroke: var(--stroke);
            stroke-width: 1;
        }
    }
    .active,
    & > svg {
        position: absolute;
        top: -30px;
        height: 83px;
    }
    & > svg {
        left: 0;
        width: 100%;
    }
    .active {
        position: absolute;
        overflow: hidden;
        left: calc(var(--l) * 1px);
        right: calc(var(--r) * 1px);
        svg {
            --stroke: var(--line-active);
            position: relative;
            left: calc(var(--l) * -1px);
            right: calc(var(--r) * -1px);
            path {
                stroke-width: 2;
            }
        }
    }
}

html {
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
}

* {
    box-sizing: inherit;
    &:before,
    &:after {
        box-sizing: inherit;
    }
}

JS

Необходимые библиотеки:

https://code.jquery.com/jquery-3.4.1.min.js
https://code.jquery.com/ui/1.12.0/jquery-ui.min.js
https://cdnjs.cloudflare.com/ajax/libs/jqueryui-touch-punch/0.2.3/jquery.ui.touch-punch.min.js
https://cdnjs.cloudflare.com/ajax/libs/gsap/2.1.3/TweenMax.min.js

скрипт

$('.slider').each(function(e) {

    var slider = $(this),
        width = slider.width(),
        handle,
        handleObj;

    let svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
    svg.setAttribute('viewBox', '0 0 ' + width + ' 83');

    slider.html(svg);
    slider.append($('<div>').addClass('active').html(svg.cloneNode(true)));

    slider.slider({
        range: true,
        values: [1800, 7800],
        min: 500,
        step: 5,
        minRange: 1000,
        max: 12000,
        create(event, ui) {

            slider.find('.ui-slider-handle').append($('<div />'));

            $(slider.data('value-0')).html(slider.slider('values', 0).toString().replace(/\B(?=(\d{3})+(?!\d))/g, '&thinsp;'));
            $(slider.data('value-1')).html(slider.slider('values', 1).toString().replace(/\B(?=(\d{3})+(?!\d))/g, '&thinsp;'));
            $(slider.data('range')).html((slider.slider('values', 1) - slider.slider('values', 0)).toString().replace(/\B(?=(\d{3})+(?!\d))/g, '&thinsp;'));

            setCSSVars(slider);

        },
        start(event, ui) {

            $('body').addClass('ui-slider-active');

            handle = $(ui.handle).data('index', ui.handleIndex);
            handleObj = slider.find('.ui-slider-handle');

        },
        change(event, ui) {
            setCSSVars(slider);
        },
        slide(event, ui) {

            let min = slider.slider('option', 'min'),
                minRange = slider.slider('option', 'minRange'),
                max = slider.slider('option', 'max');

            if(ui.handleIndex == 0) {
                if((ui.values[0] + minRange) >= ui.values[1]) {
                    slider.slider('values', 1, ui.values[0] + minRange);
                }
                if(ui.values[0] > max - minRange) {
                    return false;
                }
            } else if(ui.handleIndex == 1) {
                if((ui.values[1] - minRange) <= ui.values[0]) {
                    slider.slider('values', 0, ui.values[1] - minRange);
                }
                if(ui.values[1] < min + minRange) {
                    return false;
                }
            }

            $(slider.data('value-0')).html(ui.values[0].toString().replace(/\B(?=(\d{3})+(?!\d))/g, '&thinsp;'));
            $(slider.data('value-1')).html(ui.values[1].toString().replace(/\B(?=(\d{3})+(?!\d))/g, '&thinsp;'));
            $(slider.data('range')).html((slider.slider('values', 1) - slider.slider('values', 0)).toString().replace(/\B(?=(\d{3})+(?!\d))/g, '&thinsp;'));

            setCSSVars(slider);

        },
        stop(event, ui) {

            $('body').removeClass('ui-slider-active');

            let duration = .6,
                ease = Elastic.easeOut.config(1.08, .44);

            TweenMax.to(handle, duration, {
                '--y': 0,
                ease: ease
            });

            TweenMax.to(svgPath, duration, {
                y: 42,
                ease: ease
            });

            handle = null;

        }
    });

    var svgPath = new Proxy({
        x: null,
        y: null,
        b: null,
        a: null
    }, {
        set(target, key, value) {
            target[key] = value;
            if(target.x !== null && target.y !== null && target.b !== null && target.a !== null) {
                slider.find('svg').html(getPath([target.x, target.y], target.b, target.a, width));
            }
            return true;
        },
        get(target, key) {
            return target[key];
        }
    });

    svgPath.x = width / 2;
    svgPath.y = 42;
    svgPath.b = 0;
    svgPath.a = width;

    $(document).on('mousemove touchmove', e => {
        if(handle) {

            let laziness = 4,
                max = 24,
                edge = 52,
                other = handleObj.eq(handle.data('index') == 0 ? 1 : 0),
                currentLeft = handle.position().left,
                otherLeft = other.position().left,
                handleWidth = handle.outerWidth(),
                handleHalf = handleWidth / 2,
                y = e.pageY - handle.offset().top - handle.outerHeight() / 2,
                moveY = (y - laziness >= 0) ? y - laziness : (y + laziness <= 0) ? y + laziness : 0,
                modify = 1;

            moveY = (moveY > max) ? max : (moveY < -max) ? -max : moveY;
            modify = handle.data('index') == 0 ? ((currentLeft + handleHalf <= edge ? (currentLeft + handleHalf) / edge : 1) * (otherLeft - currentLeft - handleWidth <= edge ? (otherLeft - currentLeft - handleWidth) / edge : 1)) : ((currentLeft - (otherLeft + handleHalf * 2) <= edge ? (currentLeft - (otherLeft + handleWidth)) / edge : 1) * (slider.outerWidth() - (currentLeft + handleHalf) <= edge ? (slider.outerWidth() - (currentLeft + handleHalf)) / edge : 1));
            modify = modify > 1 ? 1 : modify < 0 ? 0 : modify;

            if(handle.data('index') == 0) {
                svgPath.b = currentLeft / 2  * modify;
                svgPath.a = otherLeft;
            } else {
                svgPath.b = otherLeft + handleHalf;
                svgPath.a = (slider.outerWidth() - currentLeft) / 2 + currentLeft + handleHalf + ((slider.outerWidth() - currentLeft) / 2) * (1 - modify);
            }

            svgPath.x = currentLeft + handleHalf;
            svgPath.y = moveY * modify + 42;

            handle.css('--y', moveY * modify);

        }
    });

});

function getPoint(point, i, a, smoothing) {
    let cp = (current, previous, next, reverse) => {
            let p = previous || current,
                n = next || current,
                o = {
                    length: Math.sqrt(Math.pow(n[0] - p[0], 2) + Math.pow(n[1] - p[1], 2)),
                    angle: Math.atan2(n[1] - p[1], n[0] - p[0])
                },
                angle = o.angle + (reverse ? Math.PI : 0),
                length = o.length * smoothing;
            return [current[0] + Math.cos(angle) * length, current[1] + Math.sin(angle) * length];
        },
        cps = cp(a[i - 1], a[i - 2], point, false),
        cpe = cp(point, a[i - 1], a[i + 1], true);
    return `C ${cps[0]},${cps[1]} ${cpe[0]},${cpe[1]} ${point[0]},${point[1]}`;
}

function getPath(update, before, after, width) {
    let smoothing = .16,
        points = [
            [0, 42],
            [before <= 0 ? 0 : before, 42],
            update,
            [after >= width ? width : after, 42],
            [width, 42]
        ],
        d = points.reduce((acc, point, i, a) => i === 0 ? `M ${point[0]},${point[1]}` : `${acc} ${getPoint(point, i, a, smoothing)}`, '');
    return `<path d="${d}" />`;
}

function setCSSVars(slider) {
    let handle = slider.find('.ui-slider-handle');
    slider.css({
        '--l': handle.eq(0).position().left + handle.eq(0).outerWidth() / 2,
        '--r': slider.outerWidth() - (handle.eq(1).position().left + handle.eq(1).outerWidth() / 2)
    });
}