frdh-mmenu-js/dist/core/scrollbugfix/mmenu.scrollbugfix.js
2022-11-18 21:38:41 +01:00

92 lines
3.6 KiB
JavaScript

import Mmenu from './../oncanvas/mmenu.oncanvas';
import options from './_options';
import { extendShorthandOptions } from './_options';
import * as DOM from '../../_modules/dom';
import * as support from '../../_modules/support';
import { extend, touchDirection } from '../../_modules/helpers';
// Add the options.
Mmenu.options.scrollBugFix = options;
export default function () {
var _this = this;
// The scrollBugFix add-on fixes a scrolling bug
// 1) on touch devices
// 2) in an off-canvas menu
// 3) that -when opened- blocks the UI from interaction
if (!support.touch || // 1
!this.opts.offCanvas || // 2
!this.opts.offCanvas.blockUI // 3
) {
return;
}
// Extend options.
var options = extendShorthandOptions(this.opts.scrollBugFix);
this.opts.scrollBugFix = extend(options, Mmenu.options.scrollBugFix);
if (!options.fix) {
return;
}
var touchDir = touchDirection(this.node.menu);
/**
* Prevent an event from doing its default and stop its propagation.
* @param {ScrollBehavior} evnt The event to stop.
*/
function stop(evnt) {
evnt.preventDefault();
evnt.stopPropagation();
}
// Prevent the page from scrolling when scrolling in the menu.
this.node.menu.addEventListener('scroll', stop, {
// Make sure to tell the browser the event will be prevented.
passive: false
});
// Prevent the page from scrolling when dragging in the menu.
this.node.menu.addEventListener('touchmove', function (evnt) {
var panel = evnt.target.closest('.mm-panel');
if (panel) {
// When dragging a non-scrollable panel,
// we can simple preventDefault and stopPropagation.
if (panel.scrollHeight === panel.offsetHeight) {
stop(evnt);
}
// When dragging a scrollable panel,
// that is fully scrolled up (or down).
// It will not trigger the scroll event when dragging down (or up) (because you can't scroll up (or down)),
// so we need to match the dragging direction with the scroll position before preventDefault and stopPropagation,
// otherwise the panel would not scroll at all in any direction.
else if (
// When scrolled up and dragging down
(panel.scrollTop == 0 && touchDir.get() == 'down') ||
// When scrolled down and dragging up
(panel.scrollHeight ==
panel.scrollTop + panel.offsetHeight &&
touchDir.get() == 'up')) {
stop(evnt);
}
// When dragging anything other than a panel.
}
else {
stop(evnt);
}
}, {
// Make sure to tell the browser the event can be prevented.
passive: false
});
// Some small additional improvements
// Scroll the current opened panel to the top when opening the menu.
this.bind('open:start', function () {
var panel = DOM.children(_this.node.pnls, '.mm-panel_opened')[0];
if (panel) {
panel.scrollTop = 0;
}
});
// Fix issue after device rotation change.
window.addEventListener('orientationchange', function (evnt) {
var panel = DOM.children(_this.node.pnls, '.mm-panel_opened')[0];
if (panel) {
panel.scrollTop = 0;
// Apparently, changing the overflow-scrolling property triggers some event :)
panel.style['-webkit-overflow-scrolling'] = 'auto';
panel.style['-webkit-overflow-scrolling'] = 'touch';
}
});
}