From a07395855a05e5e6a3cdd19d691c39d6435bdf3f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jaros=C5=82aw=20Sadzi=C5=84ski?=
 <jaroslaw.sadzinski@gmail.com>
Date: Thu, 22 Jul 2021 11:14:35 +0200
Subject: [PATCH] (core) Fixing anchor link navigation.

Summary: Last document position was overwritting anchor link navigation.

Test Plan: Browser tests

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D2934
---
 app/client/components/CursorMonitor.ts | 16 +++++++++++-----
 app/client/components/GristDoc.ts      | 10 ++++++++--
 app/common/gutil.ts                    | 21 +++++++++++++++++++--
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/app/client/components/CursorMonitor.ts b/app/client/components/CursorMonitor.ts
index 3ed1eed9..33d4e468 100644
--- a/app/client/components/CursorMonitor.ts
+++ b/app/client/components/CursorMonitor.ts
@@ -1,8 +1,8 @@
-import { CursorPos } from "app/client/components/Cursor";
-import { getStorage } from "app/client/lib/localStorageObs";
-import { IDocPage } from "app/common/gristUrls";
-import { Disposable } from "grainjs";
-import { GristDoc } from "app/client/components/GristDoc";
+import {CursorPos} from 'app/client/components/Cursor';
+import {GristDoc} from 'app/client/components/GristDoc';
+import {getStorage} from 'app/client/lib/localStorageObs';
+import {IDocPage} from 'app/common/gristUrls';
+import {Disposable} from 'grainjs';
 
 /**
  * Enriched cursor position with a view id
@@ -54,6 +54,12 @@ export class CursorMonitor extends Disposable {
   }
 
   private _whenDocumentLoadsRestorePosition(doc: GristDoc) {
+    // if doc was opened with a hash link, don't restore last position
+    if (doc.hasCustomNav.get()) {
+      this._restored = true;
+      return;
+    }
+
     // on view shown
     this.autoDispose(doc.currentView.addListener(async view => {
       // if the position was restored for this document do nothing
diff --git a/app/client/components/GristDoc.ts b/app/client/components/GristDoc.ts
index 94eaca55..adafeae1 100644
--- a/app/client/components/GristDoc.ts
+++ b/app/client/components/GristDoc.ts
@@ -43,7 +43,7 @@ import {isSchemaAction} from 'app/common/DocActions';
 import {OpenLocalDocResult} from 'app/common/DocListAPI';
 import {HashLink, IDocPage} from 'app/common/gristUrls';
 import {RecalcWhen} from 'app/common/gristTypes';
-import {encodeQueryParams, waitObs} from 'app/common/gutil';
+import {encodeQueryParams, undef, waitObs} from 'app/common/gutil';
 import {StringUnion} from 'app/common/StringUnion';
 import {TableData} from 'app/common/TableData';
 import {DocStateComparison} from 'app/common/UserAPI';
@@ -106,7 +106,8 @@ export class GristDoc extends DisposableWithEvents {
   public editorMonitor: EditorMonitor;
   // component for keeping track of a cell that is being edited
   public draftMonitor: Drafts;
-
+  // will document perform its own navigation (from anchor link)
+  public hasCustomNav: Observable<boolean>;
   // Emitter triggered when the main doc area is resized.
   public readonly resizeEmitter = this.autoDispose(new Emitter());
 
@@ -297,6 +298,11 @@ export class GristDoc extends DisposableWithEvents {
       return undefined;
     });
 
+    this.hasCustomNav = Computed.create(this, urlState().state, (_, state) => {
+      const hash = state.hash;
+      return !!(hash && (undef(hash.colRef, hash.rowId, hash.sectionId) !== undefined));
+    });
+
     this.draftMonitor = Drafts.create(this, this);
     this.cursorMonitor = CursorMonitor.create(this, this);
     this.editorMonitor = EditorMonitor.create(this, this);
diff --git a/app/common/gutil.ts b/app/common/gutil.ts
index a788b8bf..e4d2f346 100644
--- a/app/common/gutil.ts
+++ b/app/common/gutil.ts
@@ -105,8 +105,7 @@ export function undefDefault<T>(x: T|undefined, y: T): T {
 // for typescript 4
 // type Undef<T> = T extends [infer A, ...infer B] ? undefined extends A ? NonNullable<A> | Undef<B> : A : unknown;
 
-type Undef1<T> = T extends [infer A] ?
-    undefined extends A ? NonNullable<A> : A : unknown;
+type Undef1<T> = T extends [infer A] ? A : unknown;
 
 type Undef2<T> = T extends [infer A, infer B] ?
     undefined extends A ? NonNullable<A> | Undef1<[B]> : A : Undef1<T>;
@@ -117,6 +116,23 @@ type Undef3<T> = T extends [infer A, infer B, infer C] ?
 type Undef<T> = T extends [infer A, infer B, infer C, infer D] ?
     undefined extends A ? NonNullable<A> | Undef3<[B, C, D]> : A : Undef3<T>;
 
+/*
+
+Undef<T> can detect correct type that will be returned as a first defined value:
+
+const t1: number = undef(1, 1 as number | undefined);
+const t1: number | undefined = undef(2 as number | undefined, 3 as number | undefined);
+const t3: number = undef(3 as number | undefined, undefined, 4);
+const t4: number = undef(1, '');
+const t5: number = undef(1 as number | undefined, 4);
+const t6: string = undef('1', 2);
+const t7: string | number = undef(undefined, 2 as number | undefined, '3');
+const t8: string = undef(undefined, undefined, '3');
+const t9: string = undef(undefined, '2' as string | undefined, '3');
+const ta: string | number | undefined = undef(undefined, '2' as string | undefined, 3 as number | undefined);
+const tb: string | number = undef(undefined, '2' as string | undefined, 3 as number | undefined, 5);
+*/
+
 /**
  * Returns the first defined value from the list or unknown.
  * Use with typed result, so the typescript type checker can provide correct type.
@@ -128,6 +144,7 @@ export function undef<T extends Array<any>>(...list: T): Undef<T> {
   return undefined as any;
 }
 
+
 /**
  * Parses json and returns the result, or returns defaultVal if parsing fails.
  */