fix: Map & Set size diff

Author: Thanga-Ganapathy

.changeset/heavy-buttons-smile.md

@@ -0,0 +1,5 @@
+---
+"@opentf/obj-diff": minor
+---
+
+Fixed Map & Set size diff.

apps/demo/src/App.tsx

@@ -23,6 +23,16 @@ function replacer(key, value) {
     return `__INTERNAL__UNDEFINED`;
   }
 
+  if (value instanceof Map) {
+    const arr = Array.from(value);
+    return `Map(${value.size}) ${JSON.stringify(arr)}`;
+  }
+
+  if (value instanceof Set) {
+    const arr = Array.from(value);
+    return `Set(${value.size}) ${JSON.stringify(arr)}`;
+  }
+
   return value;
 }
 
@@ -142,7 +152,8 @@ function App() {
         <Box sx={{ display: "flex", justifyContent: "center", mt: 2 }}>
           <Card size="sm">
             <Typography level="body-lg">
-              🚀 The Fast, Accurate, JavaScript Objects Diffing & Patching Library.
+              🚀 The Fast, Accurate, JavaScript Objects Diffing & Patching
+              Library.
             </Typography>
           </Card>
         </Box>

apps/demo/src/Visualizer.tsx

@@ -192,6 +192,37 @@ function getRows(k, o: unknown, path = [], diff) {
     );
   }
 
+  if (o instanceof Date) {
+    rows.push(
+      <Row key={randomUUID()} path={path} diff={diff}>
+        <Box sx={{ display: "inline" }}>{k}:</Box>
+        <Box sx={{ display: "inline", ml: 2 }}>{o.toString()}</Box>,
+      </Row>
+    );
+  }
+
+  if (o instanceof Map) {
+    const arr = Array.from(o);
+    const str = `Map(${o.size}) ${JSON.stringify(arr, null, 2)}`;
+    rows.push(
+      <Row key={randomUUID()} path={path} diff={diff}>
+        <Box sx={{ display: "inline" }}>{k}:</Box>
+        <Box sx={{ display: "inline", ml: 2 }}>{str}</Box>,
+      </Row>
+    );
+  }
+
+  if (o instanceof Set) {
+    const arr = Array.from(o);
+    const str = `Set(${o.size}) ${JSON.stringify(arr, null, 2)}`;
+    rows.push(
+      <Row key={randomUUID()} path={path} diff={diff}>
+        <Box sx={{ display: "inline" }}>{k}:</Box>
+        <Box sx={{ display: "inline", ml: 2 }}>{str}</Box>,
+      </Row>
+    );
+  }
+
   return rows;
 }
 

package.json

@@ -1,6 +1,7 @@
 {
   "private": true,
   "scripts": {
+    "dev": "pnpm --filter=demo run dev",
     "build": "pnpm --filter=@opentf/obj-diff run build",
     "test": "pnpm --filter=@opentf/obj-diff run test",
     "ci": "pnpm --filter=@opentf/obj-diff run ci",

packages/obj-diff/__tests__/diff.test.ts

@@ -33,7 +33,7 @@ describe("diff", () => {
 
   test("compare object with null", () => {
     expect(diff({}, null)).toEqual([{ t: 2, p: [], v: null }]);
-    expect(diff(null, { a: 1 })).toEqual([{ t: 2, p: [], v: {a: 1} }]);
+    expect(diff(null, { a: 1 })).toEqual([{ t: 2, p: [], v: { a: 1 } }]);
   });
 
   test("empty objects", () => {
@@ -320,6 +320,34 @@ describe("diff", () => {
       )
     ).toEqual([]);
 
+    expect(
+      diff(
+        {
+          m: new Map([
+            ["x", 1],
+            ["y", 2],
+          ]),
+        },
+        {
+          m: new Map([
+            ["x", 1],
+            ["y", 2],
+            ["z", 3],
+          ]),
+        }
+      )
+    ).toEqual([
+      {
+        p: ["m"],
+        t: 2,
+        v: new Map([
+          ["x", 1],
+          ["y", 2],
+          ["z", 3],
+        ]),
+      },
+    ]);
+
     expect(
       diff(
         {
@@ -352,6 +380,10 @@ describe("diff", () => {
     let b = { s: new Set([1, 2, 3]) };
     expect(diff(a, b)).toEqual([]);
 
+    a = { s: new Set([1, 2, 3]) };
+    b = { s: new Set([1, 2, 3, 4]) };
+    expect(diff(a, b)).toEqual([{ t: 2, p: ["s"], v: new Set([1, 2, 3, 4]) }]);
+
     a = { s: new Set([1, 3, 5, 2, 4]) };
     b = { s: new Set([1, 2, 3]) };
     expect(diff(a, b)).toEqual([{ t: 2, p: ["s"], v: new Set([1, 2, 3]) }]);

packages/obj-diff/src/diff.ts

@@ -90,14 +90,22 @@ function objDiff(
     }
 
     if (a instanceof Map) {
+      if (a.size !== (b as Map<unknown, unknown>).size) {
+        return [{ t: CHANGED, p: path, v: b }];
+      }
+
       for (const k of a.keys()) {
-        if (a.get(k) !== (b as Map<unknown, unknown>).get(k)) {
+        if (!Object.is(a.get(k), (b as Map<unknown, unknown>).get(k))) {
           return [{ t: CHANGED, p: path, v: b }];
         }
       }
     }
 
     if (a instanceof Set) {
+      if (a.size !== (b as Set<unknown>).size) {
+        return [{ t: CHANGED, p: path, v: b }];
+      }
+
       for (const v of a) {
         if (!(b as Set<unknown>).has(v)) {
           return [{ t: CHANGED, p: path, v: b }];