From 82ee5d005cb35a93e5ff7b287f884bca4398f8f8 Mon Sep 17 00:00:00 2001
From: Joseph R Miles <joe@jrm.dev>
Date: Fri, 9 Jul 2021 12:25:14 -0700
Subject: [PATCH] :white_check_mark: test: Changes are applied as patches

---
 src/patching.spec.ts | 29 ++++++++++++++++++++++++++++-
 src/patching.ts      | 26 ++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/src/patching.spec.ts b/src/patching.spec.ts
index 5769d61..dcccfb4 100644
--- a/src/patching.spec.ts
+++ b/src/patching.spec.ts
@@ -1,4 +1,6 @@
-import { getChangeList, } from "./patching";
+import * as Y from "yjs";
+import { objectToYMap, } from "./mapping";
+import { getChangeList, patchSharedType, } from "./patching";
 
 describe("getChangeList", () =>
 {
@@ -74,4 +76,29 @@ describe("getChangeList", () =>
         .toEqual([ change ]);
     }
   );
+});
+
+describe("patchSharedType", () =>
+{
+  it("Applies additions to the given shared type.", () =>
+  {
+    const ydoc = new Y.Doc();
+    const ymap = ydoc.getMap("tmp");
+
+    ymap.set("state", objectToYMap({ }));
+    patchSharedType({ }, { "foo": 1, }, ymap.get("state"));
+
+    expect(ymap.get("state").get("foo")).toBe(1);
+  });
+
+  it("Applies updates to the given shared type.", () =>
+  {
+    const ydoc = new Y.Doc();
+    const ymap = ydoc.getMap("tmp");
+
+    ymap.set("state", objectToYMap({ "foo": 1, }));
+    patchSharedType({ "foo": 1, }, { "foo": 2, }, ymap.get("state"));
+
+    expect(ymap.get("state").get("foo")).toBe(2);
+  });
 });
\ No newline at end of file
diff --git a/src/patching.ts b/src/patching.ts
index 29008a2..36ee9b4 100644
--- a/src/patching.ts
+++ b/src/patching.ts
@@ -1,3 +1,4 @@
+import * as Y from "yjs";
 import { diff, } from "json-diff";
 
 export type Change = [
@@ -59,4 +60,29 @@ export const getChangeList = (a: any, b: any): Change[] =>
   }
 
   return changes;
+};
+
+export const patchSharedType = (
+  a: any,
+  b: any,
+  sharedType: Y.Map<any> | Y.Array<any>
+): any =>
+{
+  const changes = getChangeList(a, b);
+
+  changes.forEach(([ type, property, value ]) =>
+  {
+    switch (type)
+    {
+    case "add":
+    case "update":
+      if (sharedType instanceof Y.Map)
+        sharedType.set(property as string, value);
+
+      break;
+
+    default:
+      break;
+    }
+  });
 };
\ No newline at end of file