From 25edd01a1cd3847c9b62a4036a30bfcaec9c2df0 Mon Sep 17 00:00:00 2001
From: Prokop Simek <prokopsimek@users.noreply.github.com>
Date: Mon, 5 Aug 2019 19:16:05 +0200
Subject: [PATCH] feat(toposort): second element of array can be undefined
 (#37104)

---
 types/toposort/index.d.ts        |  3 ++-
 types/toposort/toposort-tests.ts | 11 ++++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/types/toposort/index.d.ts b/types/toposort/index.d.ts
index c2c9940c3a..ed94597140 100644
--- a/types/toposort/index.d.ts
+++ b/types/toposort/index.d.ts
@@ -1,7 +1,8 @@
 // Type definitions for toposort 2.0
 // Project: https://github.com/marcelklehr/toposort
 // Definitions by: Daniel Byrne <https://github.com/danwbyrne>
+//                 Prokop Simek <https://github.com/prokopsimek>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
-declare function toposort(graph: ReadonlyArray<[string, string]>): ReadonlyArray<string>;
+declare function toposort(graph: Array<[string, string | undefined]>): string[];
 export = toposort;
diff --git a/types/toposort/toposort-tests.ts b/types/toposort/toposort-tests.ts
index 84f554033b..9dcd4fa10d 100644
--- a/types/toposort/toposort-tests.ts
+++ b/types/toposort/toposort-tests.ts
@@ -1,10 +1,11 @@
 import toposort = require('toposort');
 
-const testGraph: ReadonlyArray<[string, string]> = [
-    ["string1", "string2"],
-    ["string2", "string3"],
-    ["string3", "string1"]
+const testGraph: Array<[string, string | undefined]> = [
+    ['string1', 'string2'],
+    ['string2', 'string3'],
+    ['string3', 'string1'],
+    ['string4', undefined],
 ];
 
-// $ExpectType ReadonlyArray<string>
+// $ExpectType string[]
 toposort(testGraph);