Selection_service.js

'use strict';
angular.module('mpList', []);
// This service is useful to mark items as selected, SelectAll, unselectAll,etc
// The service requieres that items must have a SID identifier property.
//
angular.module('mpList').factory('Selection',
  function () {

    var vm = {
      allSelected: false,  // Boolean: True if all items are selected, other case is False.
      someSelected: false, // Boolean: True if at least one item is selected, False if no item is selected.
      selectedCount: 0,
      itemsList: {}
    };

    function updateListInfo(selectedCount) {
      vm.allSelected = selectedCount === _.size(vm.itemsList);
      vm.selectedCount = selectedCount;
      vm.someSelected = vm.selectedCount > 0;
    }

    var init = function (items) {
      reset();
      //create keys out of each ID and set their value to false
      angular.forEach(items, function(item){
        vm.itemsList[item.sid] = false;
      });
    };

    var selectItem = function(sid) {
      // Select or deselect.
      if (angular.isUndefined(vm.itemsList[sid]))
        throw new Error('There was an error. This item may not be valid for selection.');
      vm.itemsList[sid] = !vm.itemsList[sid];
      if (vm.itemsList[sid]) {
        updateListInfo(vm.selectedCount + 1);
      } else {
        updateListInfo(vm.selectedCount - 1);
      }
    };

    var selectAll = function(select){
      // Select or deselect all.
      angular.forEach(vm.itemsList, function (val, key) {
        vm.itemsList[key] = select;
      });
      updateListInfo((select) ? _.size(vm.itemsList) : 0);
    };

    var reset = function () {
      vm.allSelected = false;
      vm.someSelected = false;
      vm.selectedCount = 0;
      vm.itemsList = {};
    };

    var getItems = function () {
      return vm.itemsList;
    };

    var getItemsCount = function () {
      return _.size(vm.itemsList);
    };

    var getItemsSelected = function () {
      // Array of sids selected
      return _.keys(_.pickBy(vm.itemsList, function (item) {
        return item;
      }));
    };

    var getItemsSelectedCount = function () {
      return vm.selectedCount;
    };

    var isSelected = function (sid) {
      if (sid in vm.itemsList) {
        return vm.itemsList[sid];
      } else {
        return false;
      }
    };

    var allSelected = function () {
      return vm.allSelected;
    };

    var someSelected = function () {
      return vm.someSelected;
    };

    var toggleSelectAll = function(){
      // Selects all if none or some items but not all are selected.
      // Deselect all items if All items were selected.
      selectAll(!allSelected());
    };


    return {
      init: init,
      selectItem: selectItem,
      selectAll: selectAll,
      reset: reset,
      getItems: getItems,
      getItemsCount: getItemsCount,
      getItemsSelected: getItemsSelected,
      getItemsSelectedCount: getItemsSelectedCount,
      isSelected: isSelected,
      allSelected: allSelected,
      someSelected: someSelected,
      toggleSelectAll: toggleSelectAll
    };
  }
);