feat(json-crdt): 🎸 add ability for file to sync to model

Author: streamich

src/json-crdt/file/File.ts

@@ -76,6 +76,22 @@ export class File implements Printable {
     this.log.push(patch);
   }
 
+  public sync(): (() => void) {
+    const {model, log} = this;
+    const api = model.api;
+    const onPatchUnsubscribe = api.onPatch.listen((patch) => {
+      log.push(patch);
+    });
+    const onLocalChangeUnsubscribe = api.onLocalChange.listen(() => {
+      const patch = api.flush();
+      if (patch.ops.length) this.log.push(patch);
+    });
+    return () => {
+      onPatchUnsubscribe();
+      onLocalChangeUnsubscribe();
+    };
+  }
+
   public serialize(params: types.FileSerializeParams = {}): types.FileWriteSequence {
     if (params.noView && params.model === 'sidecar') throw new Error('SIDECAR_MODEL_WITHOUT_VIEW');
     const metadata: types.FileMetadata = [{}, FileModelEncoding.Auto];

src/json-crdt/file/__tests__/File.spec.ts

@@ -119,3 +119,28 @@ describe('.unserialize()', () => {
     expect(file2.model.view()).toEqual({foo: 'bar', xyz: 123});
   });
 });
+
+describe('.sync()', () => {
+  test('keeps track of local changes', async () => {
+    const {file, model} = setup({foo: 'bar'});
+    file.sync();
+    model.api.obj([]).set({x: 1});
+    await Promise.resolve();
+    expect(file.model.view()).toEqual({foo: 'bar', x: 1});
+    expect(file.log.replayToEnd().view()).toEqual({foo: 'bar', x: 1});
+  });
+
+  test('keeps track of remote changes', async () => {
+    const {file, model} = setup({foo: 'bar'});
+    const clone = model.clone();
+    file.sync();
+    clone.api.obj([]).set({x: 1});
+    expect(clone.view()).toEqual({foo: 'bar', x: 1});
+    expect(file.model.view()).toEqual({foo: 'bar'});
+    const patch = clone.api.flush();
+    file.model.applyPatch(patch);
+    await Promise.resolve();
+    expect(file.model.view()).toEqual({foo: 'bar', x: 1});
+    expect(file.log.replayToEnd().view()).toEqual({foo: 'bar', x: 1});
+  });
+});