Updated documentation for ListView component

Author: estruyf

docs/documentation/docs/controls/ListView.md

@@ -67,6 +67,7 @@ The Placeholder component can be configured with the following properties:
 | selectionMode | SelectionMode | no | Specify if the items in the list view can be selected and how. Options are: none, single, multi. |
 | selection | function | no | Selection event that passes the selected item(s) from the list view. |
 | groupByFields | IGrouping[] | no | Defines the field on which you want to group the items in the list view. |
+| defaultSelection | number[] | no | The index of the items to be select by default |
 
 The `IViewField` has the following implementation:
 

src/controls/listView/IListView.ts

@@ -41,7 +41,7 @@ export interface IListViewProps {
    */
   selection?: (items: any[]) => void;
   /**
-   * The index if items to be select by default.
+   * The index of the items to be select by default
    */
   defaultSelection?: number[];
 }

src/controls/listView/ListView.tsx

@@ -58,7 +58,10 @@ export class ListView extends React.Component<IListViewProps, IListViewState> {
    * Select all the items that should be selected by default
    */
   private _setSelectedItems(): void {
-    if (this.props.items && this.props.items.length > 0 && this.props.defaultSelection && this.props.defaultSelection.length > 0) {
+    if (this.props.items &&
+        this.props.items.length > 0 &&
+        this.props.defaultSelection &&
+        this.props.defaultSelection.length > 0) {
       for (const index of this.props.defaultSelection) {
         if (index > -1) {
           this._selection.setIndexSelected(index, true, false);