From 58ae668f6486a0a46bd22fc21547ab7351c7e68d Mon Sep 17 00:00:00 2001
From: Roman Hotsiy <gotsijroman@gmail.com>
Date: Thu, 9 Aug 2018 08:44:01 +0300
Subject: [PATCH] fix: crash on any backticks code block without lang specified

---
 src/services/__tests__/prism.test.ts | 4 ++++
 src/utils/highlight.ts               | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/services/__tests__/prism.test.ts b/src/services/__tests__/prism.test.ts
index 8f982f1d..75396c7b 100644
--- a/src/services/__tests__/prism.test.ts
+++ b/src/services/__tests__/prism.test.ts
@@ -16,4 +16,8 @@ describe('prism.js helpers', () => {
   test('highlight raw text should just return text', () => {
     expect(highlight('Hello world', 'clike')).toBe('Hello world');
   });
+
+  test('highlight should not throw with lang undefined', () => {
+    expect(highlight('Hello world', undefined)).toBe('Hello world');
+  });
 });
diff --git a/src/utils/highlight.ts b/src/utils/highlight.ts
index a642e25a..feae2a3b 100644
--- a/src/utils/highlight.ts
+++ b/src/utils/highlight.ts
@@ -42,7 +42,7 @@ export function mapLang(lang: string): string {
  * @param lang highlight language
  * @return highlighted souce code as **html string**
  */
-export function highlight(source: string, lang: string): string {
+export function highlight(source: string, lang: string = DEFAULT_LANG): string {
   lang = lang.toLowerCase();
   let grammar = Prism.languages[lang];
   if (!grammar) {