feat: add serialization (save/load)

package.json

@@ -47,6 +47,7 @@
         "prosemirror-transform": "^1.3.3",
         "prosemirror-view": "1.18.7",
         "shuffle-seed": "^1.1.6",
+        "sializer": "^0.2.0",
         "ts-mocha": "^8.0.0",
         "uuid": "^3.4.0"
     },

src/micromerge.ts

@@ -14,9 +14,11 @@ import {
     getTextWithFormatting,
 } from "./peritext"
 
-const CHILDREN = Symbol("children")
-const ROOT = Symbol("_root")
-const HEAD = Symbol("_head")
+import { sia, desia } from "sializer";
+
+const CHILDREN = "children"
+const ROOT = "_root"
+const HEAD = "_head"
 
 /** A patch represents a change to make to a JSON document.
  *  These are a way for Micromerge to notify a listener of incremental changes
@@ -272,25 +274,52 @@ export default class Micromerge {
     /** Map from actorId to last sequence number seen from that actor. */
     public clock: Record<string, number> = {}
     /** Objects, keyed by the ID of the operation that created the object. */
-    private objects: Record<ObjectId, JsonComposite> & Record<typeof ROOT, Record<string, Json>> = {
-        [ROOT]: {},
-    }
+    private objects: Record<ObjectId, JsonComposite> & Record<typeof ROOT, Record<string, Json>>;
     /** Map from object ID to CRDT metadata for each object field. */
-    private metadata: Record<ObjectId, Metadata> = {
-        [ROOT]: { [CHILDREN]: {} },
-    }
+    private metadata: Record<ObjectId, Metadata>;
 
     constructor(actorId: string = uuid.v4()) {
         this.actorId = actorId
+        this.objects = {
+            [ROOT]: {},
+        }
+        this.metadata = {
+            [ROOT]: { [CHILDREN]: {} },
+        }
     }
-
     /**
      * Returns the document root object.
      */
     get root(): Record<string, Json> {
         return this.objects[ROOT]
     }
 
+    public save(): string {
+        const payload = {
+            actorId: this.actorId,
+            seq: this.seq,
+            maxOp: this.maxOp,
+            clock: this.clock,
+            objects: this.objects,
+            metadata: this.metadata
+        }
+
+        return sia(payload)
+    }
+
+    public static load(json: string): Micromerge {
+        const payload = desia(json)
+        const micromerge = new Micromerge()
+        micromerge.actorId = payload.actorId
+        micromerge.maxOp = payload.maxOp
+        micromerge.seq = payload.seq
+        micromerge.clock = payload.clock
+        micromerge.objects = payload.objects
+        micromerge.metadata = payload.metadata
+        return micromerge
+
+    }
+
     /**
      * Return the document root object, cast to a given shape.
      * The result will still make all fields optional, so the consumer

test/micromerge.ts

@@ -5,6 +5,7 @@ import type { RootDoc } from "../src/bridge"
 import { inspect } from "util"
 import { generateDocs } from "./generateDocs"
 import { accumulatePatches } from "./accumulatePatches"
+import Micromerge from '../src/micromerge';
 
 const defaultText = "The Peritext editor"
 const textChars = defaultText.split("")
@@ -47,7 +48,9 @@ const testConcurrentWrites = (args: TraceSpec): void => {
     const { initialText = "The Peritext editor", preOps, inputOps1 = [], inputOps2 = [], expectedResult } = args
 
     const { docs, patches } = generateDocs(initialText)
-    const [doc1, doc2] = docs
+    let [doc1, doc2] = docs
+    doc1 = Micromerge.load(doc1.save())
+    doc2 = Micromerge.load(doc2.save())
     let [patchesForDoc1, patchesForDoc2] = patches
 
     if (preOps) {
@@ -1414,5 +1417,17 @@ describe.only("Micromerge", () => {
 
             assert.deepStrictEqual(currentIndex, 0)
         })
+
+
+        it("de/re-serializes ", () => {
+            const { docs } = generateDocs()
+            const [doc1, doc2] = docs
+
+            let binary = doc1.save()
+            let copy = Micromerge.load(binary)
+
+            assert.deepStrictEqual(copy.getRoot(), doc1.getRoot())
+
+        })
     })
 })