smooth-scrollbar/events/wheel.js

Customize scrollbar in modern browsers with smooth scrolling experience.

import { eventScope, } from '../utils/';
export function wheelHandler(scrollbar) {
    var addEvent = eventScope(scrollbar);
    var target = scrollbar.options.delegateTo || scrollbar.containerEl;
    var eventName = ('onwheel' in window || document.implementation.hasFeature('Events.wheel', '3.0')) ? 'wheel' : 'mousewheel';
    addEvent(target, eventName, function (evt) {
        var _a = normalizeDelta(evt), x = _a.x, y = _a.y;
        scrollbar.addTransformableMomentum(x, y, evt, function (willScroll) {
            if (willScroll) {
                evt.preventDefault();
            }
        });
    });
}
// Normalizing wheel delta
var DELTA_SCALE = {
    STANDARD: 1,
    OTHERS: -3,
};
var DELTA_MODE = [1.0, 28.0, 500.0];
var getDeltaMode = function (mode) { return DELTA_MODE[mode] || DELTA_MODE[0]; };
function normalizeDelta(evt) {
    if ('deltaX' in evt) {
        var mode = getDeltaMode(evt.deltaMode);
        return {
            x: evt.deltaX / DELTA_SCALE.STANDARD * mode,
            y: evt.deltaY / DELTA_SCALE.STANDARD * mode,
        };
    }
    if ('wheelDeltaX' in evt) {
        return {
            x: evt.wheelDeltaX / DELTA_SCALE.OTHERS,
            y: evt.wheelDeltaY / DELTA_SCALE.OTHERS,
        };
    }
    // ie with touchpad
    return {
        x: 0,
        y: evt.wheelDelta / DELTA_SCALE.OTHERS,
    };
}
//# sourceMappingURL=wheel.js.map