From 0c2d5a0c30081034f9c0892c36904f533260b4f5 Mon Sep 17 00:00:00 2001
From: Damith Karunaratne <damithuom@gmail.com>
Date: Tue, 16 Mar 2021 11:30:06 +0530
Subject: [PATCH] improved change tracking not to track if value is same

---
 .gitignore                  |  1 +
 src/__tests__/index.spec.ts | 10 ++++++++++
 src/deep-equal.ts           | 25 +++++++++++++++++++++++++
 src/index.ts                | 10 ++++++++++
 4 files changed, 46 insertions(+)
 create mode 100644 src/deep-equal.ts

diff --git a/.gitignore b/.gitignore
index 009af54..5bcb6fe 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 dist
 coverage
+node_modules
diff --git a/src/__tests__/index.spec.ts b/src/__tests__/index.spec.ts
index 8f253f5..1778c84 100644
--- a/src/__tests__/index.spec.ts
+++ b/src/__tests__/index.spec.ts
@@ -585,6 +585,16 @@ describe('Sakota', () => {
         expect(proxy.__sakota__.getChanges('', /a/)).toEqual({ $set: { a: 1000 } });
         expect(proxy.__sakota__.getChanges('', /c/)).toEqual({ $unset: { c: true } });
       });
+
+      it('should not track changes if value is not changed', () => {
+        const proxy = Sakota.create({ a: 10, b: 20, c: 30 });
+        proxy.a = 10;
+        expect(proxy.__sakota__.getChanges()).toEqual({});
+        proxy.a = 12;
+        expect(proxy.__sakota__.getChanges()).toEqual({ $set: { a: 12 } });
+        proxy.a = 10;
+        expect(proxy.__sakota__.getChanges()).toEqual({});
+      });
     });
 
     describe('hasChanges', () => {
diff --git a/src/deep-equal.ts b/src/deep-equal.ts
new file mode 100644
index 0000000..5057a06
--- /dev/null
+++ b/src/deep-equal.ts
@@ -0,0 +1,25 @@
+// ref: https://stackoverflow.com/a/25456134
+
+const deepEqual = (x: any, y: any) => {
+    if (x === y) {
+        return true;
+    } else if ((typeof x == "object" && x != null) && (typeof y == "object" && y != null)) {
+        if (Object.keys(x).length != Object.keys(y).length) {
+            return false;
+        }
+
+        for (var prop in x) {
+            if (y.hasOwnProperty(prop)) {
+                if (!deepEqual(x[prop], y[prop]))
+                    return false;
+            } else {
+                return false;
+            }
+        }
+
+        return true;
+    }
+    return false;
+};
+
+export default deepEqual;
\ No newline at end of file
diff --git a/src/index.ts b/src/index.ts
index 6ab645d..c6e9f91 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,3 +1,5 @@
+import deepEqual from './deep-equal';
+
 /**
  * The key used to get the handler.
  */
@@ -237,6 +239,14 @@ export class Sakota<T extends object> implements ProxyHandler<T> {
     if (!this.diff) {
       this.diff = { $set: {}, $unset: {} };
     }
+    if (obj.hasOwnProperty(key) && deepEqual(obj[key], val)) {
+      if (this.diff.$unset[key] || this.diff.$set[key]) {
+          delete this.diff.$unset[key];
+          delete this.diff.$set[key];
+          this.onChange();
+      }
+      return true;
+    }
     delete this.diff.$unset[key];
     delete this.kids[key];
     this.diff.$set[key] = val;