(core) Revealing hidden pages with visible children.

Summary:
When a page is hidden, all its nested pages are shown as children of
a different page that happens to be before (as in pagePos) that page.

This diff shows those pages as CENSORED.

Test Plan: Updated

Reviewers: alexmojaki

Reviewed By: alexmojaki

Subscribers: alexmojaki

Differential Revision: https://phab.getgrist.com/D3670

app/client/models/TreeModel.ts

@@ -24,6 +24,7 @@ import reverse = require("lodash/reverse");
  * `TreeModel` and any item in it implements `TreeItem`.
  */
 export interface TreeNode {
+  hidden?: boolean;
   // Returns an observable array of children. Or null if the node does not accept children.
   children(): ObsArray<TreeItem>|null;
 
@@ -61,7 +62,7 @@ export interface TreeTableData {
 }
 
 // describes a function that builds dom for a particular record
-type DomBuilder = (id: number) => HTMLElement;
+type DomBuilder = (id: number, hidden: boolean) => HTMLElement;
 
 
 // Returns a list of the records from table that is suitable to build the tree model, ie: records
@@ -108,8 +109,9 @@ export function fromTableData(table: TreeTableData, buildDom: DomBuilder, oldMod
     const children = indentations[rec.indentation + 1] || [];
     delete indentations[rec.indentation + 1];
     const item = oldItems[rec.id] || new TreeItemRecord();
+    item.hidden = rec.hidden;
     item.init(storage, index, reverse(children));
-    item.buildDom = () => buildDom(rec.id);
+    item.buildDom = () => buildDom(rec.id, rec.hidden);
     siblings.push(item);
   });
   return new TreeModelRecord(storage, reverse(indentations[0] || []));
@@ -123,7 +125,7 @@ interface Storage {
 
 // TreeNode implementation that uses a grist table.
 export class TreeNodeRecord implements TreeNode {
-
+  public hidden: boolean = false;
   public storage: Storage;
   public index: number|"root";
   public children: () => ObsArray<TreeItemRecord>;
@@ -187,6 +189,7 @@ export class TreeNodeRecord implements TreeNode {
       forEach(update[0], (val, key) => values[key] = update.map(rec => rec[key]));
       const rowIds = values.id;
       delete values.id;
+      delete values.hidden;
       userActions.push(["BulkUpdateRecord", rowIds, values]);
     }