feat(deepMergeWithArray): new function

Author: antfu

src/object.test.ts

@@ -1,5 +1,5 @@
 import{describe,expect,it}from'vitest'
-import{deepMerge,objectMap}from'./object'
+import{deepMerge,deepMergeWithArray,objectMap}from'./object'
 
 it('objectMap',()=>{
 expect(objectMap({},(...args)=>args)).toEqual({})
@@ -64,3 +64,11 @@ describe('deepMerge', () => {
 expect(obj2.polluted).toBeUndefined()
 })
 })
+
+describe('deepMergeWithArray',()=>{
+it('should merge array values',()=>{
+constobj1={a: ['A','B']}
+constobj2={a: ['C'],b: ['D']}
+expect(deepMergeWithArray({},obj1,obj2)).toEqual({a: ['A','B','C'],b: ['D']})
+})
+})

src/object.ts

@@ -68,7 +68,10 @@ export function objectEntries<T extends object>(obj: T) {
 }
 
 /**
- * Deep merge :P
+ * Deep merge
+ *
+ * The first argument is the target object, the rest are the sources.
+ * The target object will be mutated and returned.
  *
  * @category Object
  */
@@ -105,6 +108,62 @@ export function deepMerge<T extends object = object, S extends object = T>(targe
 returndeepMerge(target, ...sources)
 }
 
+/**
+ * Deep merge
+ *
+ * Differs from `deepMerge` in that it merges arrays instead of overriding them.
+ *
+ * The first argument is the target object, the rest are the sources.
+ * The target object will be mutated and returned.
+ *
+ * @category Object
+ */
+exportfunctiondeepMergeWithArray<Textendsobject=object,Sextendsobject=T>(target: T, ...sources: S[]): DeepMerge<T,S>{
+if(!sources.length)
+returntargetasany
+
+constsource=sources.shift()
+if(source===undefined)
+returntargetasany
+
+if(Array.isArray(target)&&Array.isArray(source))
+target.push(...source)
+
+if(isMergableObject(target)&&isMergableObject(source)){
+objectKeys(source).forEach((key)=>{
+if(key==='__proto__'||key==='constructor'||key==='prototype')
+return
+
+// @ts-expect-error
+if(Array.isArray(source[key])){
+// @ts-expect-error
+if(!target[key])
+// @ts-expect-error
+target[key]=[]
+
+// @ts-expect-error
+deepMergeWithArray(target[key],source[key])
+}
+// @ts-expect-error
+elseif(isMergableObject(source[key])){
+// @ts-expect-error
+if(!target[key])
+// @ts-expect-error
+target[key]={}
+
+// @ts-expect-error
+deepMergeWithArray(target[key],source[key])
+}
+else{
+// @ts-expect-error
+target[key]=source[key]
+}
+})
+}
+
+returndeepMergeWithArray(target, ...sources)
+}
+
 functionisMergableObject(item: any): item is Object{
 returnisObject(item)&&!Array.isArray(item)
 }