110 lines
3 KiB
JavaScript
110 lines
3 KiB
JavaScript
// @license magnet:?xt=urn:btih:0b31508aeb0634b347b8270c7bee4d411b5d4109&dn=agpl-3.0.txt AGPL-v3-or-Later
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// Abstract Infinite Scroll View Super Class
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// Requires:
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// a stream model, assigned to this.stream
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// a stream's posts, assigned to this.collection
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// a postClass to be declared
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// a #paginate div in the layout
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// a call to setupInfiniteScroll
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app.views.InfScroll = app.views.Base.extend({
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setupInfiniteScroll : function() {
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this.postViews = this.postViews || [];
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this._resetPostFragments();
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this.bind("loadMore", this.fetchAndshowLoader, this);
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this.stream.bind("fetched", this.finishedLoading, this);
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this.stream.bind("allItemsLoaded", this.unbindInfScroll, this);
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this.collection.bind("add", this.addPostView, this);
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var throttledScroll = _.throttle(_.bind(this.infScroll, this), 200);
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$(window).scroll(throttledScroll);
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},
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_resetPostFragments: function() {
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this.appendedPosts = document.createDocumentFragment();
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this.prependedPosts = document.createDocumentFragment();
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},
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postRenderTemplate : function() {
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if(this.stream.isFetching()) { this.showLoader() }
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},
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createPostView : function(post){
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var postView = new this.postClass({ model: post, stream: this.stream });
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if (this.collection.at(0).id === post.id) {
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// post is first in collection - insert view at top of the list
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this.postViews.unshift(postView);
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} else {
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this.postViews.push(postView);
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}
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return postView;
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},
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// called for every item inserted in this.collection
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addPostView : function(post) {
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var el = this.createPostView(post).render().el;
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if (this.collection.at(0).id === post.id) {
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this.prependedPosts.insertBefore(el, this.prependedPosts.firstChild);
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} else {
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this.appendedPosts.appendChild(el);
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}
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},
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unbindInfScroll : function() {
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$(window).unbind("scroll");
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},
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renderTemplate : function(){
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this.renderInitialPosts();
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},
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renderInitialPosts : function(){
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this.$el.empty();
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var els = document.createDocumentFragment();
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this.stream.items.each(_.bind(function(post){
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els.appendChild(this.createPostView(post).render().el);
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}, this));
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this.$el.html(els);
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},
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fetchAndshowLoader : function(){
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if( this.stream.isFetching() ) return false;
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this.stream.fetch();
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this.showLoader();
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},
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showLoader: function(){
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$("#paginate .loader").removeClass("hidden");
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},
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finishedAdding: function() {
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this.$el.prepend(this.prependedPosts);
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this.$el.append(this.appendedPosts);
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this._resetPostFragments();
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},
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finishedLoading: function() {
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this.finishedAdding();
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this.hideLoader();
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},
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hideLoader: function() {
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$("#paginate .loader").addClass("hidden");
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},
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infScroll : function() {
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var $window = $(window)
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, distFromTop = $window.height() + $window.scrollTop()
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, distFromBottom = $(document).height() - distFromTop
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, bufferPx = 500;
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if(distFromBottom < bufferPx) {
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this.trigger("loadMore");
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}
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}
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});
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// @license-end
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