feat(json-crdt): 🎸 add NodeApi .replace() method

Author: streamich

src/json-crdt/model/Model.ts

@@ -272,13 +272,15 @@ export class Model<N extends JsonNode = JsonNode<any>> implements Printable {
   /**
    * Experimental node retrieval API using proxy objects. Returns a strictly
    * typed proxy wrapper around the value of the root node.
-   *
-   * @todo consider renaming this to `_`.
    */
   public get s() {
     return this.api.r.proxy().val;
   }
 
+  /**
+   * Experimental strictly typed node retrieval API using proxy objects.
+   * Automatically resolves nested "val" nodes.
+   */
   public get $() {
     return this.api.$;
   }

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

@@ -107,7 +107,11 @@ export class ModelApi<N extends JsonNode = JsonNode> implements SyncStore<JsonNo
     return new ValApi(this.model.root, this);
   }
 
-  /** @ignore */
+  /**
+   * @ignore
+   * 
+   * @todo Remove this getter?
+   */
   public get node() {
     return this.r.get();
   }
@@ -277,6 +281,10 @@ export class ModelApi<N extends JsonNode = JsonNode> implements SyncStore<JsonNo
     return this.model.view();
   }
 
+  public select(path?: ApiPath, leaf?: boolean) {
+    return this.r.select(path, leaf);
+  }
+
   /**
    * Reads the value at the given path in the model. If no path is provided,
    * returns the root node's view.
@@ -293,6 +301,10 @@ export class ModelApi<N extends JsonNode = JsonNode> implements SyncStore<JsonNo
     return this.r.add(path, value);
   }
 
+  public replace(path: ApiPath, value: unknown) {
+    return this.r.replace(path, value);
+  }
+
   private inTx = false;
   public transaction(callback: () => void) {
     if (this.inTx) callback();

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

@@ -186,6 +186,15 @@ describe('.add()', () => {
       expect(doc.api.read('/arr/1')).toBe('asdf');
       expect(success).toBe(true);
     });
+    
+    test('can add element to the beginning of array (on "arr" node)', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/arr/0')).toBe('asdf');
+      const success = doc.api.arr('/arr').add('/0', 0);
+      expect(doc.api.read('/arr/0')).toBe(0);
+      expect(doc.api.read('/arr/1')).toBe('asdf');
+      expect(success).toBe(true);
+    });
 
     test('can add element to the middle of array', () => {
       const doc = createTypedModel();
@@ -322,5 +331,61 @@ describe('.add()', () => {
   });
 });
 
+describe('.replace()', () => {
+  describe('"obj" node', () => {
+    test('can replace value in "obj" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/obj/str')).toBe('asdf');
+      const success = doc.api.replace('/obj/str', 'newValue');
+      expect(doc.api.read('/obj/str')).toBe('newValue');
+      expect(success).toBe(true);
+    });
+
+    test('can replace value in "obj" node - 2', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/obj/str')).toBe('asdf');
+      const success = doc.api.obj(['obj']).replace('/str', s.arr([s.con(true)]));
+      expect(doc.api.read('/obj/str')).toEqual([true]);
+      expect(success).toBe(true);
+    });
+
+    test('cannot replace non-existing key', () => {
+      const doc = createTypedModel();
+      const success = doc.api.replace('/obj/asdfasdf', 'newValue');
+      expect(doc.api.read('/obj/asdfasdf')).toBe(undefined);
+      expect(success).toBe(false);
+    });
+
+    test('cannot replace non-existing key - 2', () => {
+      const doc = createTypedModel();
+      const success = doc.api.obj('obj').replace('/asdfasdf', 'newValue');
+      expect(doc.api.read('/obj/asdfasdf')).toBe(undefined);
+      expect(success).toBe(false);
+    });
+  });
+  
+  describe('"arr" node', () => {
+    test('can replace "val" value in "arr" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/arr/1')).toBe(0);
+      expect(doc.api.select('/arr')?.asArr().length()).toBe(2);
+      const success = doc.api.replace('/arr/1', 'newValue');
+      expect(doc.api.read('/arr/1')).toBe('newValue');
+      expect(doc.api.select('/arr')?.asArr().length()).toBe(2);
+      expect(success).toBe(true);
+    });
+
+    test('can replace non-"val" value in "arr" node', () => {
+      const doc = createTypedModel();
+      expect(doc.api.read('/arr/0')).toBe('asdf');
+      expect(doc.api.select('/arr')?.asArr().length()).toBe(2);
+      const success = doc.api.replace('/arr/0', 'newValue');
+      expect(doc.api.read('/arr/0')).toBe('newValue');
+      expect(doc.api.select('/arr')?.asArr().length()).toBe(2);
+      expect(success).toBe(true);
+    });
+  });
+});
+
 test.todo('.merge()');
 test.todo('.shallowMerge()');

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

@@ -192,6 +192,16 @@ export class NodeApi<N extends JsonNode = JsonNode> implements Printable {
     return this.node.view() as unknown as JsonNodeView<N>;
   }
 
+  public select(path?: ApiPath, leaf?: boolean) {
+    try {
+      let node = path ? this.find(path) : this.node;
+      if (leaf) while (node instanceof ValNode) node = node.child();
+      return this.api.wrap(node);
+    } catch (e) {
+      return;
+    }
+  }
+
   public read(path?: ApiPath): unknown {
     const view = this.view();
     if (Array.isArray(path)) return get(view, path);
@@ -203,38 +213,79 @@ 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 {
-      let node: unknown = parent ? this.in(parent) : this;
+      node = parent ? this.in(parent) : this;
       while (node instanceof ValApi) node = node.in();
+    } catch {
+      return false;
+    }
+    ADD: {
       if (node instanceof ObjApi) {
         node.set({[key]: value});
-        return true;
       } else if (node instanceof ArrApi || node instanceof StrApi || node instanceof BinApi) {
         const length = node.length();
         let index: number = 0;
         if (typeof key === 'number') index = key;
         else if (key === '-') index = length;
         else {
           index = ~~key;
-          if (index + '' !== key) return false;
+          if (index + '' !== key) break ADD;
         }
-        if (index !== index) return false;
+        if (index !== index) break ADD;
         if (index < 0) index = 0;
         if (index > length) index = length;
         if (node instanceof ArrApi) {
           node.ins(index, Array.isArray(value) ? value : [value]);
         } else if (node instanceof StrApi) {
           node.ins(index, value + '');
         } else if (node instanceof BinApi) {
-          if (!(value instanceof Uint8Array)) return false;
+          if (!(value instanceof Uint8Array)) break ADD;
           node.ins(index, value);
         }
-        return true;
       } else if (node instanceof VecApi) {
         node.set([[~~key, value]]);
-        return true;
-      }
-    } catch {}
+      } else break ADD;
+      return true;
+    }
+    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: {
+      if (node instanceof ObjApi) {
+        const keyStr = key + '';
+        if (!node.has(keyStr)) break REPLACE;
+        node.set({[key]: value});
+      } else if (node instanceof ArrApi) {
+        const length = node.length();
+        let index: number = 0;
+        if (typeof key === 'number') index = key;
+        else {
+          index = ~~key;
+          if (index + '' !== key) break REPLACE;
+        }
+        if (index !== index || index < 0 || index > length - 1) break REPLACE;
+        const element = node.node.getNode(index);
+        if (element instanceof ValNode) {
+          this.api.wrap(element).set(value);
+        } else {
+          node.ins(index, [value]);
+          node.del(index + 1, 1);
+        }
+      } else if (node instanceof VecApi) {
+        node.set([[~~key, value]]);
+      } else break REPLACE;
+      return true;
+    }
     return false;
   }
 
@@ -435,6 +486,16 @@ export class ObjApi<N extends ObjNode<any> = ObjNode<any>> extends NodeApi<N> {
     api.apply();
   }
 
+  /**
+   * Checks if a key exists in the object.
+   *
+   * @param key Key to check.
+   * @returns True if the key exists, false otherwise.
+   */
+  public has(key: string): boolean {
+    return this.node.keys.has(key);
+  }
+
   /**
    * Returns a proxy object for this node. Allows to access object properties
    * by key.