fix(json-crdt-extensions): 🐛 improve .getOrNextHigher()

Author: streamich

src/json-crdt-extensions/peritext/overlay/Overlay.ts

@@ -1,6 +1,6 @@
 import {printTree} from 'tree-dump/lib/printTree';
 import {printBinary} from 'tree-dump/lib/printBinary';
-import {first, insertLeft, insertRight, next, prev, remove} from 'sonic-forest/lib/util';
+import {first, insertLeft, insertRight, last, next, prev, remove} from 'sonic-forest/lib/util';
 import {splay} from 'sonic-forest/lib/splay/util';
 import {Anchor} from '../rga/constants';
 import {Point} from '../rga/Point';
@@ -45,6 +45,10 @@ export class Overlay<T = string> implements Printable, Stateful {
     return this.root ? first(this.root) : undefined;
   }
 
+  public last(): OverlayPoint<T> | undefined {
+    return this.root ? last(this.root) : undefined;
+  }
+
   public iterator(): () => OverlayPoint<T> | undefined {
     let curr = this.first();
     return () => {
@@ -98,9 +102,11 @@ export class Overlay<T = string> implements Printable, Stateful {
    * Retrieve overlay point or the next one, measured in spacial dimension.
    */
   public getOrNextHigher(point: Point<T>): OverlayPoint<T> | undefined {
-    if (point.isAbsEnd()) point = this.txt.pointEnd()!;
-    else if (point.isAbsStart()) {
-      return undefined;
+    if (point.isAbsEnd()) {
+      const last = this.last();
+      if (!last) return;
+      if (last.isAbsEnd()) return last;
+      point = last;
     }
     let curr: OverlayPoint<T> | undefined = this.root;
     let result: OverlayPoint<T> | undefined = undefined;
@@ -111,7 +117,7 @@ export class Overlay<T = string> implements Printable, Stateful {
       else {
         const next = curr.l;
         result = curr;
-        if (!next) return result;
+        if (!next) return;
         curr = next;
       }
     }

src/json-crdt-extensions/peritext/overlay/__tests__/Overlay.getOrNextLH.spec.ts

@@ -3,6 +3,8 @@ import {size} from 'sonic-forest/lib/util';
 import {Peritext} from '../../Peritext';
 import {Anchor} from '../../rga/constants';
 import {setupNumbersWithTombstones} from '../../__tests__/setup';
+import {OverlayPoint} from '../OverlayPoint';
+import {OverlayRefSliceEnd, OverlayRefSliceStart} from '../refs';
 
 describe('.getOrNextLower()', () => {
   test('combines overlay points - right anchor', () => {
@@ -120,14 +122,28 @@ describe('.getOrNextHigher()', () => {
   });
 
   describe('when all text selected, using absolute range', () => {
-    test.skip('...', () => {
+    test('can select the ending point', () => {
       const {peritext, editor} = setupNumbersWithTombstones();
       const range = peritext.range(peritext.pointAbsStart(), peritext.pointAbsEnd());
       editor.cursor.setRange(range);
       peritext.refresh();
-      console.log(peritext + '');
-      // const overlayPoint = peritext.overlay.getOrNextHigher(peritext.pointAbsStart())!;
-      // expect(overlayPoint).toBe(undefined);
+      const overlayPoint = peritext.overlay.getOrNextHigher(peritext.pointAbsEnd())!;
+      expect(overlayPoint).toBeInstanceOf(OverlayPoint);
+      expect(overlayPoint.refs.length).toBe(1);
+      expect(overlayPoint.refs[0]).toEqual(new OverlayRefSliceEnd(editor.cursor));
+    });
+
+    test('can select the start point', () => {
+      const {peritext, editor} = setupNumbersWithTombstones();
+      const range = peritext.range(peritext.pointAbsStart(), peritext.pointAbsEnd());
+      editor.cursor.setRange(range);
+      peritext.refresh();
+      const overlayPoint = peritext.overlay.getOrNextHigher(peritext.pointAbsStart()!)!;
+      expect(overlayPoint).toBeInstanceOf(OverlayPoint);
+      expect(overlayPoint.refs.length).toBe(1);
+      expect(overlayPoint.refs[0]).toEqual(new OverlayRefSliceStart(editor.cursor));
+      expect(overlayPoint.layers.length).toBe(1);
+      expect(overlayPoint.layers[0]).toEqual(editor.cursor);
     });
   });
 });