feat(json-crdt): 🎸 implement .remove() method

Author: streamich

src/json-crdt/model/api/ModelApi.ts

@@ -297,14 +297,18 @@ export class ModelApi<N extends JsonNode = JsonNode> implements SyncStore<JsonNo
     return this.r.read(path);
   }
 
-  public add(path: ApiPath, value: unknown) {
+  public add(path: ApiPath, value: unknown): boolean {
     return this.r.add(path, value);
   }
 
-  public replace(path: ApiPath, value: unknown) {
+  public replace(path: ApiPath, value: unknown): boolean {
     return this.r.replace(path, value);
   }
 
+  public remove(path: ApiPath, length?: number): boolean {
+    return this.r.remove(path, length);
+  }
+
   private inTx = false;
   public transaction(callback: () => void) {
     if (this.inTx) callback();

src/json-crdt/model/api/__tests__/NodeApi.spec.ts

@@ -387,5 +387,105 @@ describe('.replace()', () => {
   });
 });
 
+describe('.remove()', () => {
+  describe('"obj" node', () => {
+    test('can remove value in "obj" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/obj/str')).toBe('asdf');
+      const success = doc.api.remove('/obj/str');
+      expect(doc.api.read('/obj/str')).toBe(undefined);
+      expect(success).toBe(true);
+    });
+
+    test('returns false if key does not exist', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/obj/str')).toBe('asdf');
+      const success = doc.api.remove('/obj/nonexistent');
+      expect(doc.api.read('/obj/str')).toBe('asdf');
+      expect(success).toBe(false);
+    });
+  });
+
+  describe('"arr" node', () => {
+    test('can remove value in "arr" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/arr/1')).toBe(0);
+      const success = doc.api.remove('/arr/1');
+      expect(doc.api.read('/arr/1')).toBe(undefined);
+      expect(success).toBe(true);
+    });
+
+    test('returns false if index does not exist', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/arr/1')).toBe(0);
+      const success = doc.api.remove('/arr/9999');
+      expect(doc.api.read('/arr/1')).toBe(0);
+      expect(success).toBe(false);
+    });
+
+    test('can remove two elements at once', () => {
+      const doc = Model.create(s.arr([s.con(1), s.con(2), s.con(3), s.con(4), s.con(5)]));
+      expect(doc.api.read()).toEqual([1, 2, 3, 4, 5]);
+      const success = doc.api.remove('/1', 2);
+      expect(doc.api.read()).toEqual([1, 4, 5]);
+      expect(success).toBe(true);
+    });
+  });
+
+  describe('"str" node', () => {
+    test('can remove text from "str" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/obj/str')).toBe('asdf');
+      const success = doc.api.remove('/obj/str/1', 2);
+      expect(doc.api.read('/obj/str')).toBe('af');
+      expect(success).toBe(true);
+    });
+
+    test('can remove text from "str" node - 2', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/obj/str')).toBe('asdf');
+      const success = doc.api.remove(['obj', 'str', 0]);
+      expect(doc.api.read('/obj/str')).toBe('sdf');
+      expect(success).toBe(true);
+    });
+  });
+
+  describe('"bin" node', () => {
+    test('can remove bytes from "bin" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/bin')).toEqual(new Uint8Array([1, 2, 3]));
+      const success = doc.api.remove('/bin/1', 2);
+      expect(doc.api.read('/bin')).toEqual(new Uint8Array([1]));
+      expect(success).toBe(true);
+    });
+
+    test('can remove bytes from "bin" node - 2', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/bin')).toEqual(new Uint8Array([1, 2, 3]));
+      const success = doc.api.remove(['bin', 0]);
+      expect(doc.api.read('/bin')).toEqual(new Uint8Array([2, 3]));
+      expect(success).toBe(true);
+    });
+  });
+
+  describe('"vec" node', () => {
+    test('can remove value from "vec" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/vec/0')).toBe('asdf');
+      const success = doc.api.remove('/vec/0');
+      expect(doc.api.read('/vec/0')).toBe(undefined);
+      expect(success).toBe(true);
+    });
+
+    test('returns false if index does not exist', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/vec/0')).toBe('asdf');
+      const success = doc.api.remove('/vec/9999');
+      expect(doc.api.read('/vec/0')).toBe('asdf');
+      expect(success).toBe(false);
+    });
+  });
+});
+
 test.todo('.merge()');
 test.todo('.shallowMerge()');

src/json-crdt/model/api/nodes.ts

@@ -213,14 +213,8 @@ export class NodeApi<N extends JsonNode = JsonNode> implements Printable {
 
   public add(path: ApiPath, value: unknown): boolean {
     const [parent, key] = breakPath(path);
-    let node: NodeApi<any> = this;
-    try {
-      node = parent ? this.in(parent) : this;
-      while (node instanceof ValApi) node = node.in();
-    } catch {
-      return false;
-    }
-    ADD: {
+    ADD: try {
+      const node = this.select(parent, true);
       if (node instanceof ObjApi) {
         node.set({[key]: value});
       } else if (node instanceof ArrApi || node instanceof StrApi || node instanceof BinApi) {
@@ -247,20 +241,14 @@ export class NodeApi<N extends JsonNode = JsonNode> implements Printable {
         node.set([[~~key, value]]);
       } else break ADD;
       return true;
-    }
+    } catch {}
     return false;
   }
 
   public replace(path: ApiPath, value: unknown): boolean {
     const [parent, key] = breakPath(path);
-    let node: NodeApi<any> = this;
-    try {
-      node = parent ? this.in(parent) : this;
-      while (node instanceof ValApi) node = node.in();
-    } catch {
-      return false;
-    }
-    REPLACE: {
+    REPLACE: try {
+      const node = this.select(parent, true);
       if (node instanceof ObjApi) {
         const keyStr = key + '';
         if (!node.has(keyStr)) break REPLACE;
@@ -285,7 +273,34 @@ export class NodeApi<N extends JsonNode = JsonNode> implements Printable {
         node.set([[~~key, value]]);
       } else break REPLACE;
       return true;
-    }
+    } catch {}
+    return false;
+  }
+  
+  public remove(path: ApiPath, length: number = 1): boolean {
+    const [parent, key] = breakPath(path);
+    REMOVE: try {
+      const node = this.select(parent, true);
+      if (node instanceof ObjApi) {
+        const keyStr = key + '';
+        if (!node.has(keyStr)) break REMOVE;
+        node.del([keyStr]);
+      } else if (node instanceof ArrApi || node instanceof StrApi || node instanceof BinApi) {
+        const len = node.length();
+        let index: number = 0;
+        if (typeof key === 'number') index = key;
+        else if (key === '-') index = length;
+        else {
+          index = ~~key;
+          if (index + '' !== key) break REMOVE;
+        }
+        if (index !== index || index < 0 || index > len) break REMOVE;
+        node.del(index, Math.min(length, len - index));
+      } else if (node instanceof VecApi) {
+        node.set([[~~key, void 0]]);
+      } else break REMOVE;
+      return true;
+    } catch {}
     return false;
   }