improved change tracking not to track if value is same

.gitignore

@@ -1,2 +1,3 @@
 dist
 coverage
+node_modules

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', () => {

src/deep-equal.ts

@@ -0,0 +1,24 @@
+// 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;

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;