From 9803253363105c6b0ae6f7651fc8ec11c90b14b1 Mon Sep 17 00:00:00 2001
From: David Laban <alsuren@gmail.com>
Date: Mon, 7 Jan 2019 14:53:01 +0000
Subject: [PATCH] flow type update: babel-types.isType(?string, string):
 boolean (#9275)

---
 packages/babel-types/src/validators/isType.js | 2 +-
 packages/babel-types/test/validators.js       | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/babel-types/src/validators/isType.js b/packages/babel-types/src/validators/isType.js
index 6b5e0feade..cf9a681a0a 100644
--- a/packages/babel-types/src/validators/isType.js
+++ b/packages/babel-types/src/validators/isType.js
@@ -4,7 +4,7 @@ import { FLIPPED_ALIAS_KEYS, ALIAS_KEYS } from "../definitions";
 /**
  * Test if a `nodeType` is a `targetType` or if `targetType` is an alias of `nodeType`.
  */
-export default function isType(nodeType: string, targetType: string): boolean {
+export default function isType(nodeType: ?string, targetType: string): boolean {
   if (nodeType === targetType) return true;
 
   // This is a fast-path. If the test above failed, but an alias key is found, then the
diff --git a/packages/babel-types/test/validators.js b/packages/babel-types/test/validators.js
index 4b59edeb27..ce47402881 100644
--- a/packages/babel-types/test/validators.js
+++ b/packages/babel-types/test/validators.js
@@ -136,5 +136,8 @@ describe("validators", function() {
     it("returns false if nodeType and targetType are unrelated", function() {
       expect(t.isType("ArrayExpression", "ClassBody")).toBe(false);
     });
+    it("returns false if nodeType is undefined", function() {
+      expect(t.isType(undefined, "Expression")).toBe(false);
+    });
   });
 });