From ce91cdc545bc27fdf17269eb56f217543d44c8a5 Mon Sep 17 00:00:00 2001
From: Jack Sun <syy1125@hotmail.com>
Date: Tue, 29 Aug 2017 16:45:21 -0700
Subject: [PATCH] [deepmerge] Allow partial types in deepmerge

Sometimes deepmerge is used for overwriting only a few properties in a larger object. Allowing partial types lets users deepmerge without having to typecast in those cases.
In addition, also updated the typings for arrayMerge to indicate that it will be operating on two arrays.
---
 types/deepmerge/deepmerge-tests.ts | 12 +++++++++++-
 types/deepmerge/index.d.ts         | 10 ++++++----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/types/deepmerge/deepmerge-tests.ts b/types/deepmerge/deepmerge-tests.ts
index 5467cb83f0..8e1ab07828 100644
--- a/types/deepmerge/deepmerge-tests.ts
+++ b/types/deepmerge/deepmerge-tests.ts
@@ -16,4 +16,14 @@ const expected = {
   quux: 5
 };
 
-const result = deepmerge<any>(x, y);
+const result = deepmerge(x, y);
+const anyResult = deepmerge<any>(x, y);
+
+function reverseConcat(dest: number[], src: number[]) {
+    return src.concat(dest);
+}
+
+const withOptions = deepmerge(x, y, {
+  clone: false,
+  arrayMerge: reverseConcat
+});
diff --git a/types/deepmerge/index.d.ts b/types/deepmerge/index.d.ts
index 96d0412aa6..5b5e3806bd 100644
--- a/types/deepmerge/index.d.ts
+++ b/types/deepmerge/index.d.ts
@@ -1,17 +1,19 @@
 // Type definitions for deepmerge 1.3
 // Project: https://github.com/KyleAMathews/deepmerge
 // Definitions by: marvinscharle <https://github.com/marvinscharle>
+//                 syy1125 <https://github.com/syy1125>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 export = deepmerge;
 
-declare function deepmerge<T>(x: T, y: T, options?: deepmerge.Options<T>): T;
+declare function deepmerge<T>(x: Partial<T>, y: Partial<T>, options?: deepmerge.Options): T;
+declare function deepmerge<T1, T2>(x: T1, y: T2, options?: deepmerge.Options): T1 & T2;
 
 declare namespace deepmerge {
-    interface Options<T> {
+    interface Options {
         clone?: boolean;
-        arrayMerge?(destination: T, source: T, options?: Options<T>): T;
+        arrayMerge?(destination: any[], source: any[], options?: Options): any[];
     }
 
-    function all<T>(objects: T[], options?: Options<T>): T;
+    function all<T>(objects: Array<Partial<T>>, options?: Options): T;
 }