Keep arrays as arrays #23

src/diff/index.js

@@ -1,6 +1,6 @@
 import { isDate, isEmpty, isObject, properObject } from '../utils';
 
-const diff = (lhs, rhs) => {
+const diff = (lhs, rhs, keepArrayValue = false) => {
   if (lhs === rhs) return {}; // equal return no diff
 
   if (!isObject(lhs) || !isObject(rhs)) return rhs; // return updated rhs
@@ -18,14 +18,19 @@ const diff = (lhs, rhs) => {
   }
 
   return Object.keys(r).reduce((acc, key) => {
-    if (!l.hasOwnProperty(key)) return { ...acc, [key]: r[key] }; // return added r key
 
-    const difference = diff(l[key], r[key]);
+    if (!l.hasOwnProperty(key)) return { ...acc, [key]: r[key] }; // return added r key
 
+    const difference = diff(l[key], r[key], keepArrayValue);
     if (isObject(difference) && isEmpty(difference) && !isDate(difference)) return acc; // return no diff
+    if (keepArrayValue && Array.isArray(r[key])) {
+      return { ...acc, [key]: r[key] };
+    } else {
+      return { ...acc, [key]: difference }; // return updated key
+    }
 
-    return { ...acc, [key]: difference }; // return updated key
   }, deletedValues);
 };
 
 export default diff;
+

src/diff/index.test.js

@@ -56,7 +56,7 @@ describe('.diff', () => {
       });
 
       test('returns subset of right hand side value when nested values differ', () => {
-        expect(diff({ a: { b: 1, c: 2} }, { a: { b: 1, c: 3 } })).toEqual({ a: { c: 3 } });
+        expect(diff({ a: { b: 1, c: 2 } }, { a: { b: 1, c: 3 } })).toEqual({ a: { c: 3 } });
       });
 
       test('returns subset of right hand side value when nested values differ at multiple paths', () => {
@@ -72,7 +72,7 @@ describe('.diff', () => {
       });
 
       test('returns keys as undefined when deleted from right hand side', () => {
-        expect(diff({ a: 1, b: { c: 2 }}, { a: 1 })).toEqual({ b: undefined });
+        expect(diff({ a: 1, b: { c: 2 } }, { a: 1 })).toEqual({ b: undefined });
       });
     });
 
@@ -139,7 +139,7 @@ describe('.diff', () => {
 
       test('returns subset of right hand side value when nested values differ', () => {
         const lhs = Object.create(null);
-        lhs.a = { b: 1, c: 2};
+        lhs.a = { b: 1, c: 2 };
         const rhs = Object.create(null);
         rhs.a = { b: 1, c: 3 };
         expect(diff(lhs, rhs)).toEqual({ a: { c: 3 } });
@@ -172,6 +172,28 @@ describe('.diff', () => {
         rhs.b = 2;
         expect(diff(lhs, rhs)).toEqual({ b: 2 });
       });
+
+      test('returns value of modified array', () => {
+        const lhs = Object.create(null);
+        lhs.a = [1];
+        const rhs = Object.create(null);
+        rhs.a = [1];
+        rhs.a.push(2)
+        expect(diff(lhs, rhs, true)).toEqual(rhs);
+      });
+
+      test('returns value of modified array in nested object', () => {
+        const lhs = Object.create(null);
+        lhs.foo = { bar: [1] };
+        lhs.a = 1
+        const rhs = Object.create(null);
+        rhs.a = 1
+        rhs.foo = { bar: [1] };
+        rhs.foo.bar.push(2)
+        const res = diff(lhs, rhs, true);
+        console.log(res);
+        expect(res).toEqual({ foo: { bar: [1, 2] } });
+      });
     });
   });
 });