function SortByStoreOrder(elem) { return this.store.index(elem.id); } var default_sort = SortByStoreOrder; var default_filt = function(elem){ return true; }; function StoreView(store, filt, sortfun) { EventEmitter.call(this); filt = filt || default_filt; sortfun = sortfun || default_sort; this.store = store; this.add = this.add.bind(this); this.update = this.update.bind(this); this.remove = this.remove.bind(this); this.recalculate = this.recalculate.bind(this); this.store.addListener("add", this.add); this.store.addListener("update", this.update); this.store.addListener("remove", this.remove); this.store.addListener("recalculate", this.recalculate); this.recalculate(this.store.list, filt, sortfun); } _.extend(StoreView.prototype, EventEmitter.prototype, { close: function () { this.store.removeListener("add", this.add); this.store.removeListener("update", this.update); this.store.removeListener("remove", this.remove); this.store.removeListener("recalculate", this.recalculate); }, recalculate: function (elems, filt, sortfun) { if (filt) { this.filt = filt; } if (sortfun) { this.sortfun = sortfun.bind(this); } this.list = elems.filter(this.filt); this.list.sort(function (a, b) { return this.sortfun(a) - this.sortfun(b); }.bind(this)); this.emit("recalculate"); }, index: function (elem) { return _.sortedIndex(this.list, elem, this.sortfun); }, add: function (elem) { if (this.filt(elem)) { var idx = this.index(elem); if (idx === this.list.length) { //happens often, .push is way faster. this.list.push(elem); } else { this.list.splice(idx, 0, elem); } this.emit("add", elem, idx); } }, update: function (elem) { var idx; var i = this.list.length; // Search from the back, we usually update the latest entries. while (i--) { if (this.list[i].id === elem.id) { idx = i; break; } } if (idx === -1) { //not contained in list this.add(elem); } else if (!this.filt(elem)) { this.remove(elem.id); } else { if (this.sortfun(this.list[idx]) !== this.sortfun(elem)) { //sortpos has changed this.remove(this.list[idx]); this.add(elem); } else { this.list[idx] = elem; this.emit("update", elem, idx); } } }, remove: function (elem_id) { var idx = this.list.length; while (idx--) { if (this.list[idx].id === elem_id) { this.list.splice(idx, 1); this.emit("remove", elem_id, idx); break; } } } });