areaInfoのデフォルト値が間違っていたのを修正

components/発車時刻表/LED_vidion.js

@@ -162,6 +162,7 @@ export default function LED_vision(props) {
     true
   );
   useEffect(() => {
+    if (!areaInfo) return () => {};
     setAreaString(
       areaInfo.substring(move, areaInfo.length) + areaInfo.substring(0, move)
     );

stateBox/useAreaInfo.js

@@ -1,6 +1,6 @@
 import React, { createContext, useContext, useState } from "react";
 const initialState = {
-  areaInfo: [],
+  areaInfo: "",
   setAreainfo: () => {},
 };
 
@@ -11,7 +11,7 @@ export const useAreaInfo = () => {
 };
 
 export const AreaInfoProvider = ({ children }) => {
-  const [areaInfo, setAreaInfo] = useState([]);
+  const [areaInfo, setAreaInfo] = useState("");
 
   return (
     <AreaInfoContext.Provider value={{ areaInfo, setAreaInfo }}>