From a9c67da7192ea19daffea664a94dfbd19ef49d28 Mon Sep 17 00:00:00 2001
From: Robert Stocks <stocksr@users.noreply.github.com>
Date: Fri, 27 Sep 2019 00:06:08 +0100
Subject: [PATCH] lodash: fix flattenDeep to correctly handle strings (#38625)

* lodash: fix flattenDeep to correctly handle strings

* fix whitespace
---
 types/lodash/ts3.1/common/array.d.ts | 4 +++-
 types/lodash/ts3.1/lodash-tests.ts   | 3 +++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/types/lodash/ts3.1/common/array.d.ts b/types/lodash/ts3.1/common/array.d.ts
index 73e4e642c2..3831ba97ce 100644
--- a/types/lodash/ts3.1/common/array.d.ts
+++ b/types/lodash/ts3.1/common/array.d.ts
@@ -488,7 +488,9 @@ declare module "../index" {
          */
         flatten(): T extends Many<infer U> ? CollectionChain<U> : CollectionChain<T>;
     }
-    type Flat<T> = (T extends List<any> ? never : T);
+
+    type Flat<T> = T extends string ? T : (T extends List<any> ? never : T);
+
     interface LoDashStatic {
         /**
          * Recursively flattens a nested array.
diff --git a/types/lodash/ts3.1/lodash-tests.ts b/types/lodash/ts3.1/lodash-tests.ts
index 339f1f2c3e..927a8fae8c 100644
--- a/types/lodash/ts3.1/lodash-tests.ts
+++ b/types/lodash/ts3.1/lodash-tests.ts
@@ -497,6 +497,9 @@ _.chain([1, 2, 3, 4]).unshift(5, 6); // $ExpectType CollectionChain<number>
     _.flattenDeep([1, [2, [3, [4, 5]]]]); // $ExpectType number[]
     _.flattenDeep({0: 1, 1: [2, [3, [4, 5]]], length: 2}); // $ExpectType number[]
 
+    _.flattenDeep(['x']); // $ExpectType string[]
+    _.flattenDeep(['x', ['y']]); // $ExpectType string[]
+
     _.flattenDeep<number>([1, 2, 3]); // $ExpectType number[]
     _.flattenDeep<number>([[1, 2, 3]]); // $ExpectType number[]
     _.flattenDeep<number>([1, [2, [3, [4, 5]]]]); // $ExpectType number[]