feat(json-crdt): 🎸 add ability to encode file without model view

Author: streamich

src/json-crdt/file/File.ts

@@ -62,7 +62,8 @@ export class File implements Printable {
   constructor(public readonly model: Model, public readonly log: PatchLog) {}
 
   public serialize(params: types.FileSerializeParams = {}): types.FileWriteSequence {
-    const view = this.model.view();
+    if (params.noView && (params.model === 'sidecar'))
+      throw new Error('SIDECAR_MODEL_WITHOUT_VIEW');
     const metadata: types.FileMetadata = [{}, FileModelEncoding.Auto];
     let model: Uint8Array | unknown | null = null;
     const modelFormat = params.model ?? 'sidecar';
@@ -123,7 +124,7 @@ export class File implements Printable {
       default:
         throw new Error(`Invalid history format: ${patchFormat}`);
     }
-    return [view, metadata, model, history];
+    return [params.noView ? null : this.model.view(), metadata, model, history];
   }
 
   public toBinary(params: types.FileEncodingParams): Uint8Array {

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

@@ -3,6 +3,7 @@ import {Model} from '../../model';
 import {File} from '../File';
 import {JsonDecoder} from '../../../json-pack/json/JsonDecoder';
 import {CborDecoder} from '../../../json-pack/cbor/CborDecoder';
+import {FileEncodingParams} from '../types';
 
 const setup = (view: unknown) => {
   const model = Model.withServerClock();
@@ -68,4 +69,36 @@ describe('.toBinary()', () => {
       expect(file.log.replayToEnd().view()).toEqual({foo: 'bar'});
     });
   });
+
+  const assertEncoding = (file: File, params: FileEncodingParams) => {
+    const blob = file.toBinary(params);
+    // if (params.format === 'ndjson') console.log(Buffer.from(blob).toString('utf8'))
+    const file2 = params.format === 'seq.cbor' ? File.fromSeqCbor(blob) : File.fromNdjson(blob);
+    expect(file2.model.view()).toEqual(file.model.view());
+    expect(file2.model !== file.model).toBe(true);
+    expect(file2.log.start.view()).toEqual(undefined);
+    expect(file2.log.replayToEnd().view()).toEqual(file.model.view());
+    expect(file2.log.patches.size()).toBe(file.log.patches.size());
+  };
+
+  describe('can encode/decode all format combinations', () => {
+    const formats: FileEncodingParams['format'][] = ['ndjson', 'seq.cbor'];
+    const modelFormats: FileEncodingParams['model'][] = ['sidecar', 'binary', 'compact', 'verbose'];
+    const historyFormats: FileEncodingParams['history'][] = ['binary', 'compact', 'verbose'];
+    const noViews = [true, false];
+    for (const format of formats) {
+      for (const model of modelFormats) {
+        for (const history of historyFormats) {
+          for (const noView of noViews) {
+            if (noView && (model === 'sidecar')) continue;
+            const params = {format, model, history, noView};
+            test(JSON.stringify(params), () => {
+              const {file} = setup({foo: 'bar'});
+              assertEncoding(file, params);
+            });
+          }
+        }
+      }
+    }
+  });
 });

src/util/trees/avl/AvlMap.ts

@@ -72,6 +72,15 @@ export class AvlMap<K, V> implements Printable {
     return !!this.find(k);
   }
 
+  public size(): number {
+    const root = this.root;
+    if (!root) return 0;
+    let curr = first(root);
+    let size = 1;
+    while ((curr = next(curr as HeadlessNode) as AvlNode<K, V> | undefined)) size++;
+    return size;
+  }
+
   public getOrNextLower(k: K): AvlNode<K, V> | undefined {
     return (findOrNextLower(this.root, k, this.comparator) as AvlNode<K, V>) || undefined;
   }