feat: support deep merge

Author: zombieJ

src/utils/set.ts

@@ -66,10 +66,25 @@ function createEmpty<T>(source: T) {
 
 const keys = typeof Reflect === 'undefined' ? Object.keys : Reflect.ownKeys;
 
+// ================================ Merge ================================
+export type MergeFn = (srcVal: any, tgtVal: any) => any;
+
 /**
- * Merge objects which will create
+ * Merge multiple objects. Support custom merge logic.
+ * @param sources object sources
+ * @param config.prepareArray Customize array prepare function.
+ * It will return empty [] by default.
+ * So when match array, it will auto be override with next array in sources.
  */
-export function merge<T extends object>(...sources: T[]) {
+export function deepMerge<T extends object>(
+  sources: T[],
+  config: {
+    prepareArray?: MergeFn;
+  } = {},
+) {
+  const { prepareArray } = config;
+  const finalPrepareArray: MergeFn = prepareArray || (() => []);
+
   let clone = createEmpty(sources[0]);
 
   sources.forEach(src => {
@@ -89,7 +104,7 @@ export function merge<T extends object>(...sources: T[]) {
 
           if (isArr) {
             // Array will always be override
-            clone = set(clone, path, []);
+            clone = set(clone, path, finalPrepareArray(originValue, value));
           } else if (!originValue || typeof originValue !== 'object') {
             // Init container if not exist
             clone = set(clone, path, createEmpty(value));
@@ -109,3 +124,10 @@ export function merge<T extends object>(...sources: T[]) {
 
   return clone;
 }
+
+/**
+ * Merge objects which will create
+ */
+export function merge<T extends object>(...sources: T[]) {
+  return deepMerge(sources);
+}

tests/utils.test.ts

@@ -1,6 +1,6 @@
 import pickAttrs from '../src/pickAttrs';
 import get from '../src/utils/get';
-import set, { merge } from '../src/utils/set';
+import set, { deepMerge, merge } from '../src/utils/set';
 
 describe('utils', () => {
   it('get', () => {
@@ -252,6 +252,39 @@ describe('utils', () => {
           [symbol]: 1,
         });
       });
+
+      it('deepMerge for custom logic', () => {
+        const src = {
+          rest: 233,
+          list: [
+            {
+              a: 1,
+            },
+          ],
+        };
+        const tgt = {
+          list: [
+            {
+              b: 1,
+            },
+          ],
+        };
+
+        const merged = deepMerge<any>([src, tgt], {
+          prepareArray: srcVal => {
+            return [...(srcVal || [])];
+          },
+        });
+        expect(merged).toEqual({
+          rest: 233,
+          list: [
+            {
+              a: 1,
+              b: 1,
+            },
+          ],
+        });
+      });
     });
   });