fix crash simpler way

Author: williamstein

src/package.json

@@ -6,6 +6,7 @@
     "make": "pnpm run build",
     "make-dev": "pnpm run build-dev",
     "build": "./workspaces.py install && ./workspaces.py build && pnpm python-api",
+    "tsc-all": "./workspaces.py tsc --parallel",
     "build-dev": "./workspaces.py install && ./workspaces.py build --dev && pnpm python-api",
     "clean": "rm -rf packages/node_modules && ./workspaces.py clean && cd compute/compute && pnpm clean ",
     "hub": "cd packages/hub && npm run hub-project-dev-nobuild",

src/packages/jupyter/util/cell-utils.ts

@@ -113,6 +113,9 @@ export function new_cell_pos(
     Returned undefined whenever don't really know what to do; then caller
     just makes up a pos, and it'll get sorted out.
   */
+  if (cells == null) {
+    return 0;
+  }
   let cell_list_0: List<string>;
   if (cell_list == null) {
     cell_list_0 = sorted_cell_list(cells)!;
@@ -129,8 +132,8 @@ export function new_cell_pos(
       return false; // break iteration
     }
   });
-  const adjacent_pos = cells?.getIn([adjacent_id, "pos"]) as number | undefined;
-  const current_pos = (cells?.getIn([cur_id, "pos"]) ?? 0) as number;
+  const adjacent_pos = cells.getIn([adjacent_id, "pos"]) as number | undefined;
+  const current_pos = cells.getIn([cur_id, "pos"]) as number;
   let pos: number;
   if (adjacent_pos != null) {
     // there is a cell after (or before) cur_id cell