Strict nulls for everything except logconsole

buildutils/src/ensure-repo.ts

@@ -304,7 +304,7 @@ export async function ensureIntegrity(): Promise<boolean> {
         return;
       }
       const depData = graph.getNodeData(depName);
-      if (depData.style) {
+      if (typeof depData.style === 'string') {
         cssData[depName] = [depData.style];
       }
     });

examples/cell/src/index.ts

@@ -62,11 +62,13 @@ function main(): void {
 
   // Handle the mimeType for the current kernel.
   session.kernelChanged.connect(() => {
-    void session.kernel.ready.then(() => {
-      const lang = session.kernel.info.language_info;
-      const mimeType = mimeService.getMimeTypeByLanguage(lang);
-      cellWidget.model.mimeType = mimeType;
-    });
+    if (session.kernel) {
+      void session.kernel.ready.then(() => {
+        const lang = session.kernel!.info!.language_info;
+        const mimeType = mimeService.getMimeTypeByLanguage(lang);
+        cellWidget.model.mimeType = mimeType;
+      });
+    }
   });
 
   // Use the default kernel.

packages/apputils/src/clipboard.ts

@@ -77,17 +77,21 @@ export namespace Clipboard {
     // Select the node content.
     let range = document.createRange();
     range.selectNodeContents(node);
-    sel.removeAllRanges();
-    sel.addRange(range);
+    if (sel) {
+      sel.removeAllRanges();
+      sel.addRange(range);
+    }
 
     // Execute the command.
     document.execCommand(type);
 
     // Restore the previous selection.
     sel = window.getSelection();
-    sel.removeAllRanges();
-    for (let i = 0, len = savedRanges.length; i < len; ++i) {
-      sel.addRange(savedRanges[i]);
+    if (sel) {
+      sel.removeAllRanges();
+      for (let i = 0, len = savedRanges.length; i < len; ++i) {
+        sel.addRange(savedRanges[i]);
+      }
     }
   }
 }

packages/apputils/src/mainareawidget.ts

@@ -103,6 +103,9 @@ export class MainAreaWidget<T extends Widget = Widget> extends Widget
    * Print method. Defered to content.
    */
   [Printing.symbol](): Printing.OptionalAsyncThunk {
+    if (!this._content) {
+      return null;
+    }
     return Printing.getPrintFunction(this._content);
   }
 
@@ -158,14 +161,16 @@ export class MainAreaWidget<T extends Widget = Widget> extends Widget
    * Handle `'update-request'` messages by forwarding them to the content.
    */
   protected onUpdateRequest(msg: Message): void {
-    MessageLoop.sendMessage(this._content, msg);
+    if (this._content) {
+      MessageLoop.sendMessage(this._content, msg);
+    }
   }
 
   /**
    * Update the title based on the attributes of the child widget.
    */
   private _updateTitle(): void {
-    if (this._changeGuard) {
+    if (this._changeGuard || !this.content) {
       return;
     }
     this._changeGuard = true;
@@ -184,7 +189,7 @@ export class MainAreaWidget<T extends Widget = Widget> extends Widget
    * Update the content title based on attributes of the main widget.
    */
   private _updateContentTitle(): void {
-    if (this._changeGuard) {
+    if (this._changeGuard || !this.content) {
       return;
     }
     this._changeGuard = true;
@@ -203,6 +208,9 @@ export class MainAreaWidget<T extends Widget = Widget> extends Widget
    * Give focus to the content.
    */
   private _focusContent(): void {
+    if (!this.content) {
+      return;
+    }
     // Focus the content node if we aren't already focused on it or a
     // descendent.
     if (!this.content.node.contains(document.activeElement)) {

packages/apputils/src/windowresolver.ts

@@ -158,7 +158,7 @@ namespace Private {
       known[reported] = null;
 
       // If a reported window name and candidate collide, reject the candidate.
-      if (candidate in known) {
+      if (!candidate || candidate in known) {
         reject();
       }
     });
@@ -212,7 +212,7 @@ namespace Private {
 
       // If the window name has not already been resolved, check one last time
       // to confirm it is not a duplicate before resolving.
-      if (candidate in known) {
+      if (!candidate || candidate in known) {
         return reject();
       }
 

packages/cells/src/widget.ts

@@ -1224,15 +1224,19 @@ export abstract class AttachmentsCell extends Cell {
    * Handle the `paste` event for the widget
    */
   private _evtPaste(event: ClipboardEvent): void {
-    this._attachFiles(event.clipboardData.items);
+    if (event.clipboardData) {
+      this._attachFiles(event.clipboardData.items);
+    }
     event.preventDefault();
   }
 
   /**
    * Handle the `drop` event for the widget
    */
   private _evtNativeDrop(event: DragEvent): void {
-    this._attachFiles(event.dataTransfer.items);
+    if (event.dataTransfer) {
+      this._attachFiles(event.dataTransfer.items);
+    }
     event.preventDefault();
   }
 
@@ -1297,7 +1301,9 @@ export abstract class AttachmentsCell extends Cell {
       const item = items[i];
       if (item.kind === 'file') {
         const blob = item.getAsFile();
-        this._attachFile(blob);
+        if (blob) {
+          this._attachFile(blob);
+        }
       }
     }
   }

packages/codeeditor/src/widget.ts

@@ -252,13 +252,6 @@ export class CodeEditorWrapper extends Widget {
     if (data === undefined) {
       return;
     }
-    this.removeClass(DROP_TARGET_CLASS);
-    event.preventDefault();
-    event.stopPropagation();
-    if (event.proposedAction === 'none') {
-      event.dropAction = 'none';
-      return;
-    }
     const coordinate = {
       top: event.y,
       bottom: event.y,
@@ -270,6 +263,16 @@ export class CodeEditorWrapper extends Widget {
       height: 0
     };
     const position = this.editor.getPositionForCoordinate(coordinate);
+    if (position === null) {
+      return;
+    }
+    this.removeClass(DROP_TARGET_CLASS);
+    event.preventDefault();
+    event.stopPropagation();
+    if (event.proposedAction === 'none') {
+      event.dropAction = 'none';
+      return;
+    }
     const offset = this.editor.getOffsetAt(position);
     this.model.value.insert(offset, data);
   }

packages/codemirror-extension/src/index.ts

@@ -86,7 +86,7 @@ export const editorSyntaxStatus: JupyterFrontEndPlugin<void> = {
     let item = new EditorSyntaxStatus({ commands: app.commands });
     labShell.currentChanged.connect(() => {
       const current = labShell.currentWidget;
-      if (current && tracker.has(current)) {
+      if (current && tracker.has(current) && item.model) {
         item.model.editor = (current as IDocumentWidget<
           FileEditor
         >).content.editor;

packages/completer/src/model.ts

@@ -325,15 +325,16 @@ export class CompleterModel implements Completer.IModel {
   createPatch(patch: string): Completer.IPatch | undefined {
     const original = this._original;
     const cursor = this._cursor;
+    const current = this._current;
 
-    if (!original || !cursor) {
+    if (!original || !cursor || !current) {
       return undefined;
     }
 
     let { start, end } = cursor;
     // Also include any filtering/additional-typing that has occurred
     // since the completion request in the patched length.
-    end = end + (this.current.text.length - this.original.text.length);
+    end = end + (current.text.length - original.text.length);
 
     return { start, end, value: patch };
   }

packages/completer/src/widget.ts

@@ -820,7 +820,10 @@ namespace Private {
   export function itemValues(items: NodeList): string[] {
     let values: string[] = [];
     for (let i = 0, len = items.length; i < len; i++) {
-      values.push((items[i] as HTMLElement).getAttribute('data-value'));
+      const attr = (items[i] as HTMLElement).getAttribute('data-value');
+      if (attr) {
+        values.push(attr);
+      }
     }
     return values;
   }

packages/console-extension/src/index.ts

@@ -40,7 +40,7 @@ import { IRenderMimeRegistry } from '@jupyterlab/rendermime';
 
 import { find } from '@lumino/algorithm';
 
-import { ReadonlyJSONObject, JSONObject } from '@lumino/coreutils';
+import { JSONObject, ReadonlyPartialJSONObject } from '@lumino/coreutils';
 
 import { DisposableSet } from '@lumino/disposable';
 
@@ -333,7 +333,11 @@ async function activateConsole(
         const kernelPreference = args[
           'kernelPreference'
         ] as IClientSession.IKernelPreference;
-        return manager.specs.kernelspecs[kernelPreference.name].display_name;
+        return (
+          // TODO: Lumino command functions should probably be allowed to return undefined?
+          manager.specs?.kernelspecs[kernelPreference.name || '']
+            ?.display_name ?? ''
+        );
       }
       return 'Console';
     },

packages/console/src/widget.ts

@@ -799,7 +799,7 @@ export class CodeConsole extends Widget {
           if (this.isDisposed || !kernel || !kernel.info) {
             return;
           }
-          this._handleInfo(this.session.kernel.info);
+          this._handleInfo(kernel.info);
         })
         .catch(err => {
           console.error('could not get kernel info');

packages/coreutils/src/statedb.ts

@@ -190,7 +190,9 @@ export class StateDB<T extends ReadonlyJSONValue = ReadonlyJSONValue>
    */
   private async _merge(contents: StateDB.Content<T>): Promise<void> {
     await Promise.all(
-      Object.keys(contents).map(key => this._save(key, contents[key]))
+      Object.keys(contents).map(
+        key => contents[key] && this._save(key, contents[key]!)
+      )
     );
   }
 

packages/csvviewer/src/parse.ts

@@ -468,7 +468,7 @@ export function parseDSV(options: IParser.IOptions): IParser.IResults {
     }
   }
 
-  return { nrows, ncols: columnOffsets ? ncols : 0, offsets };
+  return { nrows, ncols: columnOffsets ? ncols ?? 0 : 0, offsets };
 }
 
 /**
@@ -571,5 +571,5 @@ export function parseDSVNoQuotes(options: IParser.IOptions): IParser.IResults {
     currRow = rowEnd + rowDelimiterLength;
   }
 
-  return { nrows, ncols: columnOffsets ? ncols : 0, offsets };
+  return { nrows, ncols: columnOffsets ? ncols ?? 0 : 0, offsets };
 }

packages/csvviewer/src/widget.ts

@@ -106,6 +106,7 @@ export class GridSearchService {
           return config.matchBackgroundColor;
         }
       }
+      return '';
     };
   }
 

packages/docmanager/src/manager.ts

@@ -88,6 +88,9 @@ export class DocumentManager implements IDocumentManager {
     // For each existing context, start/stop the autosave handler as needed.
     this._contexts.forEach(context => {
       const handler = Private.saveHandlerProperty.get(context);
+      if (!handler) {
+        return;
+      }
       if (value === true && !handler.isActive) {
         handler.start();
       } else if (value === false && handler.isActive) {
@@ -109,6 +112,9 @@ export class DocumentManager implements IDocumentManager {
     // For each existing context, set the save interval as needed.
     this._contexts.forEach(context => {
       const handler = Private.saveHandlerProperty.get(context);
+      if (!handler) {
+        return;
+      }
       handler.saveInterval = value || 120;
     });
   }

packages/docregistry/src/mimedocument.ts

@@ -188,10 +188,12 @@ export class MimeContent extends Widget {
       if (data !== this._context.model.toString()) {
         this._context.model.fromString(data);
       }
-    } else {
-      if (!JSONExt.deepEqual(data, this._context.model.toJSON())) {
-        this._context.model.fromJSON(data);
-      }
+    } else if (
+      data !== null &&
+      data !== undefined &&
+      !JSONExt.deepEqual(data, this._context.model.toJSON())
+    ) {
+      this._context.model.fromJSON(data);
     }
   };
 

packages/documentsearch/src/providers/codemirrorsearchprovider.ts

@@ -307,7 +307,7 @@ export class CodeMirrorSearchProvider
   private _onDocChanged(_: any, changeObj: CodeMirror.EditorChange) {
     // If we get newlines added/removed, the line numbers across the
     // match state are all shifted, so here we need to recalculate it
-    if (changeObj.text.length > 1 || changeObj.removed.length > 1) {
+    if (changeObj.text.length > 1 || (changeObj.removed?.length ?? 0) > 1) {
       this._setInitialMatches(this._query);
       this._changed.emit(undefined);
     }

packages/filebrowser-extension/src/index.ts

@@ -469,11 +469,13 @@ function addCommands(
         const item = await Private.navigateToPath(path, factory);
         if (item.type !== 'directory') {
           const browserForPath = Private.getBrowserForPath(path, factory);
-          browserForPath.clearSelectedItems();
-          const parts = path.split('/');
-          const name = parts[parts.length - 1];
-          if (name) {
-            await browserForPath.selectItemByName(name);
+          if (browserForPath) {
+            browserForPath.clearSelectedItems();
+            const parts = path.split('/');
+            const name = parts[parts.length - 1];
+            if (name) {
+              await browserForPath.selectItemByName(name);
+            }
           }
         }
       } catch (reason) {
@@ -989,7 +991,9 @@ namespace Private {
       .execute('launcher:create', { cwd: model.path })
       .then((launcher: MainAreaWidget<Launcher>) => {
         model.pathChanged.connect(() => {
-          launcher.content.cwd = model.path;
+          if (launcher.content) {
+            launcher.content.cwd = model.path;
+          }
         }, launcher);
         return launcher;
       });