feat(json-crdt-extensions): 🎸 improve slice deletions

src/json-crdt-extensions/peritext/Peritext.ts

@@ -212,7 +212,7 @@ export class Peritext<T = string> implements Printable {
     return this.range(start, end);
   }
 
-  // --------------------------------------------------------------------- text
+  // ---------------------------------------------------------- text (& slices)
 
   /**
    * Insert plain text at a view position in the text.
@@ -247,7 +247,7 @@ export class Peritext<T = string> implements Printable {
   }
 
   public del(range: Range<T>): void {
-    // this.delSlices(range);
+    this.delSlices(range);
     this.delStr(range);
   }
 
@@ -274,13 +274,16 @@ export class Peritext<T = string> implements Printable {
     return true;
   }
 
-  // public delSlices(range: Range): void {
-  //   this.overlay.refresh();
-  //   range = range.clone();
-  //   range.expand();
-  //   const slices = this.overlay.findContained(range);
-  //   this.slices.delMany(Array.from(slices));
-  // }
+  public delSlices(range: Range<T>): void {
+    this.overlay.refresh();
+    range = range.range();
+    range.expand();
+    const slices = this.overlay.findContained(range);
+    if (!slices.size) return;
+    this.savedSlices.delSlices(slices);
+    this.extraSlices.delSlices(slices);
+    this.localSlices.delSlices(slices);
+  }
 
   // public delSlice(sliceId: ITimestampStruct): void {
   //   this.slices.del(sliceId);

src/json-crdt-extensions/peritext/__tests__/Peritext.cursor.spec.ts

@@ -135,5 +135,3 @@ test('cursor can move across block boundary forwards', () => {
     [SliceTypes.Cursor]: [[[CursorAnchor.Start, void 0]], InlineAttrPos.Collapsed],
   });
 });
-
-test.todo('moving past text end keeps cursor at text end');

src/json-crdt-extensions/peritext/__tests__/Peritext.deletions.spec.ts

@@ -0,0 +1,47 @@
+import {setupAlphabetChunkSplitKit, setupAlphabetKit, Kit, setupAlphabetWithDeletesKit, setupAlphabetWithTwoChunksKit} from './setup';
+
+const run = (setup: () => Kit) => {
+  describe('.delAt()', () => {
+    test('can delete text', () => {
+      const {peritext} = setup();
+      peritext.delAt(0, 1);
+      peritext.delAt(0, 2);
+      peritext.delAt(1, 2);
+      peritext.delAt(3, 15);
+      peritext.delAt(4, 2);
+      expect(peritext.str.view()).toBe('dghx');
+    });
+
+    test('deletes slice if it is contained in deletion range', () => {
+      const {peritext, editor} = setup();
+      editor.cursor.setAt(2, 2);
+      editor.saved.insOverwrite('underline');
+      editor.cursor.setAt(0);
+      peritext.refresh();
+      expect(editor.saved.slices.size()).toBe(1);
+      peritext.delAt(1, 3);
+      peritext.refresh();
+      expect(editor.saved.slices.size()).toBe(0);
+    });
+
+    test('does not delete slice if it is only partially contained', () => {
+      const {peritext, editor} = setup();
+      editor.cursor.setAt(2, 10);
+      editor.extra.insOverwrite('underline');
+      editor.cursor.setAt(0);
+      peritext.refresh();
+      expect(peritext.extraSlices.size()).toBe(1);
+      peritext.delAt(1, 10);
+      peritext.refresh();
+      expect(peritext.extraSlices.size()).toBe(1);
+      peritext.delAt(1, 10);
+      peritext.refresh();
+      expect(peritext.extraSlices.size()).toBe(0);
+    });
+  });
+};
+
+describe('basic alphabet', () => run(setupAlphabetKit));
+describe('alphabet with chunk splits', () => run(setupAlphabetChunkSplitKit));
+describe('alphabet with deletes', () => run(setupAlphabetWithDeletesKit));
+describe('alphabet with two chunks', () => run(setupAlphabetWithTwoChunksKit));

src/json-crdt-extensions/peritext/editor/Editor.ts

@@ -70,7 +70,12 @@ export class Editor<T = string> {
    * the range is removed and the text is inserted at the start of the range.
    */
   public insert(text: string): void {
-    this.cursors((cursor) => cursor.insert(text));
+    let cnt = 0;
+    this.cursors((cursor) => {
+      cnt++;
+      cursor.insert(text);
+    });
+    if (!cnt) this.cursor.insert(text);
   }
 
   /**

src/json-crdt-extensions/peritext/editor/EditorSlices.ts

@@ -9,7 +9,7 @@ import type {Cursor} from './Cursor';
 export class EditorSlices<T = string> {
   constructor(
     protected readonly txt: Peritext<T>,
-    protected readonly slices: Slices<T>,
+    public readonly slices: Slices<T>,
   ) {}
 
   protected insAtCursors<S extends PersistedSlice<T>>(callback: (cursor: Cursor<T>) => S): S[] {

src/json-crdt-extensions/peritext/slice/Slices.ts

@@ -141,17 +141,16 @@ export class Slices<T = string> implements Stateful, Printable {
     api.apply();
   }
 
-  public delSlices(slices: Slice[]): void {
+  public delSlices(slices: Iterable<Slice<T>>): void {
     const api = this.set.doc.api;
     const spans: ITimespanStruct[] = [];
-    const length = slices.length;
-    for (let i = 0; i < length; i++) {
-      const slice = slices[i];
+    for (const slice of slices) {
       if (slice instanceof PersistedSlice) {
         const id = slice.id;
         spans.push(new Timespan(id.sid, id.time, 1));
       }
     }
+    if (!spans.length) return;
     api.builder.del(this.set.id, spans);
     api.apply();
   }