feat(json-crdt-extensions): 🎸 can return block marker when iterating

src/json-crdt-extensions/peritext/block/Block.ts

@@ -50,12 +50,16 @@ export class Block<Attr = unknown> implements IBlock, Printable, Stateful {
    * Iterate through all overlay points of this block, until the next marker
    * (regardless if that marker is a child or not).
    */
-  public points0(): UndefIterator<OverlayPoint<T>> {
+  public points0(withMarker: boolean = false): UndefIterator<OverlayPoint<T>> {
     const txt = this.txt;
     const overlay = txt.overlay;
     const iterator = overlay.points0(this.marker);
     let closed = false;
     return () => {
+      if (withMarker) {
+        withMarker = false;
+        return this.marker ?? overlay.START;
+      }
       if (closed) return;
       const point = iterator();
       if (!point) return;
@@ -67,8 +71,8 @@ export class Block<Attr = unknown> implements IBlock, Printable, Stateful {
     };
   }
 
-  public points(): IterableIterator<OverlayPoint<T>> {
-    return new UndefEndIter(this.points0());
+  public points(withMarker?: boolean): IterableIterator<OverlayPoint<T>> {
+    return new UndefEndIter(this.points0(withMarker));
   }
 
   // ----------------------------------------------------------------- Stateful

src/json-crdt-extensions/peritext/block/__tests__/Block.iteration.spec.ts

@@ -1,4 +1,5 @@
 import {setupHelloWorldKit} from '../../__tests__/setup';
+import {MarkerOverlayPoint} from '../../overlay/MarkerOverlayPoint';
 import {OverlayPoint} from '../../overlay/OverlayPoint';
 
 describe('points', () => {
@@ -11,6 +12,16 @@ describe('points', () => {
     expect(iterator()).toBe(undefined);
   });
 
+  test('using flag, can receive START marker in empty document', () => {
+    const {peritext} = setupHelloWorldKit();
+    peritext.refresh();
+    const blocks = peritext.blocks;
+    const block = blocks.root.children[0]!;
+    const iterator = block.points0(true);
+    expect(iterator()).toBeInstanceOf(OverlayPoint);
+    expect(iterator()).toBe(undefined);
+  });
+
   test('returns all overlay points in single block document', () => {
     const {peritext} = setupHelloWorldKit();
     peritext.editor.cursor.setAt(3, 3);
@@ -26,8 +37,22 @@ describe('points', () => {
     expect(point3).toBe(undefined);
   });
 
-  test('returns only points within that block, in two-block document', () => {
+  test('returns all overlay points in single block document, including start marker', () => {
     const {peritext} = setupHelloWorldKit();
+    peritext.editor.cursor.setAt(3, 3);
+    peritext.editor.saved.insStack('bold');
+    peritext.refresh();
+    const block = peritext.blocks.root.children[0]!;
+    const iterator = block.points0(true);
+    expect(iterator()).toBeInstanceOf(OverlayPoint);
+    expect(iterator()).toBeInstanceOf(OverlayPoint);
+    expect(iterator()).toBeInstanceOf(OverlayPoint);
+    expect(iterator()).toBe(undefined);
+  });
+
+  const setupTwoBlockDocument = () => {
+    const kit = setupHelloWorldKit();
+    const {peritext} = kit;
     peritext.editor.cursor.setAt(1, 2);
     peritext.editor.saved.insStack('bold');
     peritext.editor.cursor.setAt(7, 2);
@@ -38,6 +63,11 @@ describe('points', () => {
     peritext.editor.saved.insMarker('p');
     peritext.editor.delCursors();
     peritext.refresh();
+    return kit;
+  };
+
+  test('returns only points within that block, in two-block document', () => {
+    const {peritext} = setupTwoBlockDocument();
     expect(peritext.blocks.root.children.length).toBe(2);
     const block1 = peritext.blocks.root.children[0]!;
     const block2 = peritext.blocks.root.children[1]!;
@@ -46,4 +76,18 @@ describe('points', () => {
     expect(points1.length).toBe(2);
     expect(points2.length).toBe(4);
   });
+
+  test('can iterate including marker points, in two-block document', () => {
+    const {peritext} = setupTwoBlockDocument();
+    expect(peritext.blocks.root.children.length).toBe(2);
+    const block1 = peritext.blocks.root.children[0]!;
+    const block2 = peritext.blocks.root.children[1]!;
+    const points1 = [...block1.points(true)];
+    const points2 = [...block2.points(true)];
+    expect(points1.length).toBe(3);
+    expect(points2.length).toBe(5);
+    expect(points1[0]).toBeInstanceOf(OverlayPoint);
+    expect(points1[0]).toBe(peritext.overlay.START);
+    expect(points2[0]).toBeInstanceOf(MarkerOverlayPoint);
+  });
 });