Add plugin save and restore api to perspective-viewer-datagrid

packages/perspective-viewer-datagrid/src/js/datagrid.js

@@ -116,4 +116,17 @@ export class DatagridViewModel extends DatagridViewEventModel {
             this.appendChild(this.table_model.table);
         }
     }
+
+    save() {
+        const selected = this._get_selected();
+        if (selected !== undefined) {
+            return {selected};
+        }
+    }
+
+    restore(config) {
+        if (config.selected) {
+            this._set_selected(config.selected);
+        }
+    }
 }

packages/perspective-viewer-datagrid/src/js/events.js

@@ -185,6 +185,32 @@ export class DatagridViewEventModel extends DatagridVirtualTableViewModel {
             }
         }
     }
+    /**
+     * Get the id of the selected row
+     *
+     * @memberof DatagridVirtualTableViewModel
+     */
+    _get_selected() {
+        return this._selected_id;
+    }
+    /**
+     * sets the selected row to the `selected_id`. The row for the id
+     * will be highlighted if it's in the viewport
+     *
+     * @param {*} selected_id
+     * @memberof DatagridVirtualTableViewModel
+     */
+    _set_selected(selected_id) {
+        this._selected_id = selected_id;
+    }
+    /**
+     * Clears selected row
+     *
+     * @memberof DatagridVirtualTableViewModel
+     */
+    _clear_selected() {
+        delete this._selected_id;
+    }
 
     /**
      * Datagrid event which handles row selection.
@@ -198,13 +224,13 @@ export class DatagridViewEventModel extends DatagridVirtualTableViewModel {
             return;
         }
 
-        const is_deselect = isEqual(metadata.id, this._selected_id);
+        const is_deselect = isEqual(metadata.id, this._get_selected());
         let filters = [];
         if (is_deselect) {
-            this._selected_id = undefined;
+            this._clear_selected();
             await this.draw({invalid_viewport: true});
         } else {
-            this._selected_id = metadata.id;
+            this._set_selected(metadata.id);
             await this.draw({invalid_viewport: true});
             filters = await getCellConfig(this._view_cache, metadata.ridx, metadata.cidx);
             filters = filters.config.filters;

packages/perspective-viewer-datagrid/src/js/index.js

@@ -66,6 +66,10 @@ class DatagridPlugin {
     static async create(div, view) {
         const datagrid = get_or_create_datagrid(this, div);
         const options = await datagrid.set_view(view);
+        if (this._plugin_config) {
+            datagrid.restore(this._plugin_config);
+            delete this._plugin_config;
+        }
         await datagrid.draw(options);
     }
 
@@ -76,6 +80,29 @@ class DatagridPlugin {
             await datagrid.draw({invalid_viewport: true});
         }
     }
+
+    static delete() {
+        if (this.view && VIEWER_MAP.has(this._datavis)) {
+            const datagrid = VIEWER_MAP.get(this._datavis);
+            datagrid.clear();
+        }
+    }
+
+    static save() {
+        if (this.view && VIEWER_MAP.has(this._datavis)) {
+            const datagrid = VIEWER_MAP.get(this._datavis);
+            return datagrid.save();
+        }
+    }
+
+    static restore(config) {
+        if (this.view && VIEWER_MAP.has(this._datavis)) {
+            const datagrid = VIEWER_MAP.get(this._datavis);
+            datagrid.restore(config);
+        } else {
+            this._plugin_config = config;
+        }
+    }
 }
 
 /**