From 4eb811cea573fc7cf600a750ae4aec32708864d0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juho=20Veps=C3=A4l=C3=A4inen?= <bebraw@gmail.com>
Date: Tue, 18 Aug 2020 18:37:45 +0200
Subject: [PATCH] fix: Allow overriding an object field with null

Closes #144.
---
 CHANGELOG.md       |  4 ++++
 src/join-arrays.ts |  4 ++++
 test/merge.test.ts | 14 ++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5583859..568fd40 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## 5.1.2 / 2020-08-18
+
+- Fix - Allow overriding an object field with `null` #144
+
 ## 5.1.1 / 2020-08-04
 
 - Fix - Drop `<reference types="webpack-dev-server" />` from **index.d.ts** #143
diff --git a/src/join-arrays.ts b/src/join-arrays.ts
index d05c45b..3254089 100644
--- a/src/join-arrays.ts
+++ b/src/join-arrays.ts
@@ -61,5 +61,9 @@ function isFunction(functionToCheck) {
 }
 
 function isPlainObject(a) {
+  if (a === null) {
+    return false;
+  }
+
   return typeof a === "object";
 }
diff --git a/test/merge.test.ts b/test/merge.test.ts
index 9712d43..c5cd39a 100644
--- a/test/merge.test.ts
+++ b/test/merge.test.ts
@@ -27,6 +27,20 @@ function normalMergeTest(merge, loadersKey) {
     assert.deepEqual(merge([]), {});
   });
 
+  it.only("should override with null (#144)", function () {
+    const result = { devServer: null };
+
+    assert.deepEqual(
+      merge(
+        {
+          devServer: { base: true },
+        },
+        result
+      ),
+      result
+    );
+  });
+
   it("should error on promise", function () {
     const a = {
       module: {},