[modern-react] 리액트 스터디 파일 추가

2025-09-30 23:55:13 +09:00
parent 31bcb2efe1
commit 75ec02d506
546 changed files with 141345 additions and 0 deletions
--- a/modern-react/my-modern/optional.js
+++ b/modern-react/my-modern/optional.js
@@ -0,0 +1,13 @@
+const str = null;
+console.log(str.substring(1));
+    
+// if (str !== null && str !== undefined) {
+//   console.log(str.substring(1));
+// }
+
+// const str = null;
+// console.log(str?.substring(1));
+
+// const str = '위키북스';
+// console.log(str?.substring(1));
+