[ADF-621] show drop effect on folders only (#1897)

* show drop effect on folders only

- fix `hasValue` api for data rows (avoid 'false' value to be evaluated as missing value)
- support for evaluating drop support for rows
- document list enables upload zones for folders only

* api improvements as per code review

ng2-components/ng2-alfresco-datatable/src/components/datatable/datatable.component.html

@@ -32,7 +32,7 @@
     <tr *ngFor="let row of data.getRows(); let idx = index" tabindex="0"
         class="alfresco-datatable__row"
         [class.alfresco-datatable__row--selected]="selectedRow === row"
-        [adf-upload]="allowDropFiles" [adf-upload-data]="row">
+        [adf-upload]="allowDropFiles && rowAllowsDrop(row)" [adf-upload-data]="row">
 
         <!-- Actions (left) -->
         <td *ngIf="actions && actionsPosition === 'left'" class="alfresco-datatable__actions-cell">

ng2-components/ng2-alfresco-datatable/src/components/datatable/datatable.component.ts

@@ -264,4 +264,8 @@ export class DataTableComponent implements AfterContentInit, OnChanges {
             this.executeRowAction.emit(new DataRowActionEvent(row, action));
         }
     }
+
+    rowAllowsDrop(row: DataRow): boolean {
+        return row.isDropTarget === true;
+    }
 }

ng2-components/ng2-alfresco-datatable/src/data/datatable-adapter.ts

@@ -32,6 +32,7 @@ export interface DataTableAdapter {
 
 export interface DataRow {
     isSelected: boolean;
+    isDropTarget?: boolean;
     hasValue(key: string): boolean;
     getValue(key: string): any;
 }

ng2-components/ng2-alfresco-datatable/src/data/object-datatable-adapter.ts

@@ -209,7 +209,7 @@ export class ObjectDataRow implements DataRow {
     }
 
     hasValue(key: string): boolean {
-        return this.getValue(key) ? true : false;
+        return this.getValue(key) !== undefined;
     }
 }
 

ng2-components/ng2-alfresco-documentlist/src/data/share-datatable-adapter.ts

@@ -234,6 +234,7 @@ export class ShareDataRow implements DataRow {
 
     cache: { [key: string]: any } = {};
     isSelected: boolean = false;
+    readonly isDropTarget;
 
     get node(): NodeMinimalEntry {
         return this.obj;
@@ -243,6 +244,8 @@ export class ShareDataRow implements DataRow {
         if (!obj) {
             throw new Error(ShareDataRow.ERR_OBJECT_NOT_FOUND);
         }
+
+        this.isDropTarget = obj.entry && obj.entry.isFolder;
     }
 
     cacheValue(key: string, value: any): any {
@@ -258,7 +261,7 @@ export class ShareDataRow implements DataRow {
     }
 
     hasValue(key: string): boolean {
-        return this.getValue(key) ? true : false;
+        return this.getValue(key) !== undefined;
     }
 }