devextreme/dist/transpiled/events/core/wheel.js

HTML5 JavaScript Component Suite for Responsive Web Development

"use strict";

var $ = require("../../core/renderer"),
    eventsEngine = require("../../events/core/events_engine"),
    domAdapter = require("../../core/dom_adapter"),
    callOnce = require("../../core/utils/call_once"),
    registerEvent = require("./event_registrator"),
    eventUtils = require("../utils");

var EVENT_NAME = "dxmousewheel",
    EVENT_NAMESPACE = "dxWheel";

var getWheelEventName = callOnce(function () {
    return domAdapter.hasDocumentProperty("onwheel") ? "wheel" : "mousewheel";
});

var wheel = {

    setup: function setup(element) {
        var $element = $(element);
        eventsEngine.on($element, eventUtils.addNamespace(getWheelEventName(), EVENT_NAMESPACE), wheel._wheelHandler.bind(wheel));
    },

    teardown: function teardown(element) {
        eventsEngine.off(element, "." + EVENT_NAMESPACE);
    },

    _wheelHandler: function _wheelHandler(e) {
        var delta = this._getWheelDelta(e.originalEvent);

        eventUtils.fireEvent({
            type: EVENT_NAME,
            originalEvent: e,
            delta: delta,
            pointerType: "mouse"
        });

        e.stopPropagation();
    },

    _getWheelDelta: function _getWheelDelta(event) {
        return event.wheelDelta ? event.wheelDelta : -event.deltaY * 30;
    }

};

registerEvent(EVENT_NAME, wheel);

exports.name = EVENT_NAME;