Enable strict null checks (#15)

* Enable strict null checks

* Keep the undefined sentinel value in ordered tags

* Improve ordering code

Co-authored-by: Frederic COLLONVAL <fcollonval@gmail.com>

Author: jtpio

package.json

@@ -55,6 +55,7 @@
     "@jupyterlab/settingregistry": "^3.0.0",
     "@jupyterlab/ui-components": "^3.0.0",
     "@lumino/commands": "^1.12.0",
+    "@lumino/coreutils": "^1.5.3",
     "@lumino/disposable": "^1.4.3",
     "@lumino/widgets": "^1.16.1"
   },

src/celltoolbartracker.ts

@@ -109,8 +109,10 @@ export class CellToolbarTracker implements IDisposable {
       this._settings.changed.disconnect(this._onSettingsChanged, this);
     }
 
-    const cells = this._panel.context.model.cells;
-    cells.changed.disconnect(this.updateConnectedCells, this);
+    const cells = this._panel?.context.model.cells;
+    if (cells) {
+      cells.changed.disconnect(this.updateConnectedCells, this);
+    }
     this._panel = null;
   }
 
@@ -162,8 +164,8 @@ export class CellToolbarTracker implements IDisposable {
     }
   }
 
-  private _getCell(model: ICellModel): Cell {
-    return this._panel.content.widgets.find(widget => widget.model === model);
+  private _getCell(model: ICellModel): Cell | undefined {
+    return this._panel?.content.widgets.find(widget => widget.model === model);
   }
 
   private _findToolbarWidgets(cell: Cell): Widget[] {
@@ -185,7 +187,7 @@ export class CellToolbarTracker implements IDisposable {
    */
   private _onSettingsChanged(): void {
     // Update menu items
-    const leftItems = (this._settings.composite['leftMenu'] as any) as
+    const leftItems = (this._settings?.composite['leftMenu'] as any) as
       | ICellMenuItem[]
       | null;
     // Test to avoid useless signal emission
@@ -199,7 +201,7 @@ export class CellToolbarTracker implements IDisposable {
     } else {
       this._leftMenuItems.pushAll(DEFAULT_LEFT_MENU);
     }
-    const rightItems = ((this._settings.composite['rightMenu'] as any) ||
+    const rightItems = ((this._settings?.composite['rightMenu'] as any) ||
       []) as ICellMenuItem[];
     // Test to avoid useless signal emission
     if (this._rightMenuItems.length > 0) {
@@ -211,7 +213,7 @@ export class CellToolbarTracker implements IDisposable {
 
     // Update tags
     const newDefaultTags =
-      (this._settings.composite['defaultTags'] as string[]) || [];
+      (this._settings?.composite['defaultTags'] as string[]) || [];
     // Update default tag in shared tag list
     const toAdd = newDefaultTags.filter(
       tag => !this._previousDefaultTags.includes(tag)
@@ -226,11 +228,13 @@ export class CellToolbarTracker implements IDisposable {
 
     // Update left space
     const leftSpace = (this._settings?.composite['leftSpace'] as number) || 0;
-    this._panel.node
-      .querySelectorAll(`div.${LEFT_SPACER_CLASSNAME}`)
-      .forEach(node => {
-        (node as HTMLElement).style.width = `${leftSpace}px`;
-      });
+    if (this._panel) {
+      this._panel.node
+        .querySelectorAll(`div.${LEFT_SPACER_CLASSNAME}`)
+        .forEach(node => {
+          (node as HTMLElement).style.width = `${leftSpace}px`;
+        });
+    }
   }
 
   private _allTags: ObservableList<string> = new ObservableList<string>();
@@ -240,7 +244,7 @@ export class CellToolbarTracker implements IDisposable {
     ICellMenuItem
   >();
   private _previousDefaultTags = new Array<string>();
-  private _panel: NotebookPanel;
+  private _panel: NotebookPanel | null;
   private _rightMenuItems: ObservableList<ICellMenuItem> = new ObservableList<
     ICellMenuItem
   >();

src/index.ts

@@ -16,7 +16,8 @@ const extension: JupyterFrontEndPlugin<void> = {
     app: JupyterFrontEnd,
     settingRegistry: ISettingRegistry | null
   ) => {
-    const settings = await settingRegistry.load(`${EXTENSION_ID}:plugin`);
+    const settings =
+      (await settingRegistry?.load(`${EXTENSION_ID}:plugin`)) ?? null;
     app.docRegistry.addWidgetExtension(
       'Notebook',
       new CellBarExtension(app.commands, settings)

src/tagbar.ts

@@ -133,12 +133,14 @@ export class TagTool extends Widget {
     });
 
     // Sort the widgets in tag alphabetical order
-    //  - undefined matches the AddTag widget
-    const orderedTags = allTags.concat([undefined]);
     [...layout.widgets].forEach((widget: Widget, index: number) => {
-      const tagIndex = orderedTags.findIndex(
+      let tagIndex = allTags.findIndex(
         tag => (widget as TagWidget).name === tag
       );
+      // Handle AddTag widget case
+      if (tagIndex === -1) {
+        tagIndex = allTags.length;
+      }
       if (tagIndex !== index) {
         layout.insertWidget(tagIndex, widget);
       }
@@ -186,7 +188,7 @@ export class TagTool extends Widget {
    */
   protected onCellMetadataChanged(
     metadata: IObservableJSON,
-    changes: IObservableMap.IChangedArgs<ReadonlyPartialJSONValue>
+    changes: IObservableMap.IChangedArgs<ReadonlyPartialJSONValue | undefined>
   ): void {
     if (changes.key === 'tags') {
       const oldTags = [...new Set((changes.oldValue as string[]) || [])];

tsconfig.json

@@ -16,7 +16,7 @@
     "outDir": "lib",
     "rootDir": "src",
     "strict": true,
-    "strictNullChecks": false,
+    "strictNullChecks": true,
     "target": "es2017",
     "types": []
   },