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nodebb/public/src/client/infinitescroll.js

91 lines
2.2 KiB
JavaScript

'use strict';
define('forum/infinitescroll', function () {
var scroll = {};
var callback;
var previousScrollTop = 0;
var loadingMore = false;
var container;
scroll.init = function (el, cb) {
if (typeof el === 'function') {
callback = el;
container = $('body');
} else {
callback = cb;
container = el || $('body');
}
$(window).off('scroll', onScroll).on('scroll', onScroll);
};
function onScroll() {
var bsEnv = utils.findBootstrapEnvironment();
var mobileComposerOpen = (bsEnv === 'xs' || bsEnv === 'sm') && $('html').hasClass('composing');
if (loadingMore || mobileComposerOpen) {
return;
}
var currentScrollTop = $(window).scrollTop();
var wh = $(window).height();
var viewportHeight = container.height() - wh;
var offsetTop = container.offset() ? container.offset().top : 0;
var scrollPercent = 100 * (currentScrollTop - offsetTop) / (viewportHeight <= 0 ? wh : viewportHeight);
var top = 20;
var bottom = 80;
var direction = currentScrollTop > previousScrollTop ? 1 : -1;
if (scrollPercent < top && currentScrollTop < previousScrollTop) {
callback(direction);
} else if (scrollPercent > bottom && currentScrollTop > previousScrollTop) {
callback(direction);
} else if (scrollPercent < 0 && direction > 0 && viewportHeight < 0) {
callback(direction);
}
previousScrollTop = currentScrollTop;
}
scroll.loadMore = function (method, data, callback) {
if (loadingMore) {
return;
}
loadingMore = true;
var hookData = { method: method, data: data };
$(window).trigger('action:infinitescroll.loadmore', hookData);
socket.emit(hookData.method, hookData.data, function (err, data) {
if (err) {
loadingMore = false;
return app.alertError(err.message);
}
callback(data, function () {
loadingMore = false;
});
});
};
scroll.removeExtra = function (els, direction, count) {
if (els.length <= count) {
return;
}
var removeCount = els.length - count;
if (direction > 0) {
var height = $(document).height();
var scrollTop = $(window).scrollTop();
els.slice(0, removeCount).remove();
$(window).scrollTop(scrollTop + ($(document).height() - height));
} else {
els.slice(els.length - removeCount).remove();
}
};
return scroll;
});