Install and setup i18n packages

next-i18next.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+    i18n: {
+        defaultLocale: 'ja',
+        locales: ['en', 'ja'],
+    }
+}

next.config.js

@@ -1,5 +1,6 @@
 /** @type {import('next').NextConfig} */
 const path = require('path')
+const { i18n } = require('./next-i18next.config')
 
 module.exports = {
   reactStrictMode: true,
@@ -7,6 +8,7 @@ module.exports = {
     prependData: '@import "variables";',
     includePaths: [path.join(__dirname, 'styles')],
   },
+  i18n,
   async rewrites() {
     return [
       {

package.json

@@ -22,14 +22,19 @@
     "@types/axios": "^0.14.0",
     "axios": "^0.25.0",
     "classnames": "^2.3.1",
+    "i18next": "^21.6.13",
+    "i18next-browser-languagedetector": "^6.1.3",
+    "i18next-http-backend": "^1.3.2",
     "lodash.clonedeep": "^4.5.0",
     "lodash.debounce": "^4.0.8",
     "meyer-reset-scss": "^2.0.4",
     "next": "12.0.8",
+    "next-i18next": "^10.5.0",
+    "next-remote-watch": "^1.0.0",
     "react": "17.0.2",
     "react-cookie": "^4.1.1",
     "react-dom": "^17.0.2",
-    "react-i18next": "^11.15.3",
+    "react-i18next": "^11.15.5",
     "react-linkify": "^1.0.0-alpha",
     "react-scroll": "^1.8.5",
     "sass": "^1.49.0",