Handle SSR check of JWT

Author: chrissearle

frontend/app/composables/jwt.ts

@@ -1,36 +1,43 @@
-import type { User } from '@/types/user'
+import type {User} from '@/types/user'
 
 export const useJwt = () => {
-  const parseJwt = (token: string): User | undefined => {
-    const base64Payload = token.split('.')[1]
+    const parseJwt = (token: string): User | undefined => {
+        const base64Payload = token.split('.')[1]
 
-    if (base64Payload === undefined) {
-      return undefined
-    }
+        if (base64Payload === undefined) {
+            return undefined
+        }
 
-    const base64 = base64Payload.replace(/-/g, '+').replace(/_/g, '/')
+        const base64 = base64Payload.replace(/-/g, '+').replace(/_/g, '/')
 
-    const jsonPayload = decodeURIComponent(
-      window
-        .atob(base64)
-        .split('')
-        .map(function (c) {
-          return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
-        })
-        .join('')
-    )
+        let jsonPayload: string
 
-    const jsonUser = JSON.parse(jsonPayload)
+        if (typeof window !== 'undefined') {
+            // Running in browser
+            jsonPayload = decodeURIComponent(
+                window
+                    .atob(base64)
+                    .split('')
+                    .map((c) => '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2))
+                    .join('')
+            )
+        } else {
+            // Running in Node (SSR)
+            const buffer = Buffer.from(base64, 'base64')
+            jsonPayload = buffer.toString('utf-8')
+        }
 
-    return {
-      id: jsonUser['slack_id'],
-      name: jsonUser['name'],
-      avatar: jsonUser['avatar'],
-      email: jsonUser['email'],
+        const jsonUser = JSON.parse(jsonPayload)
+
+        return {
+            id: jsonUser['slack_id'],
+            name: jsonUser['name'],
+            avatar: jsonUser['avatar'],
+            email: jsonUser['email'],
+        }
     }
-  }
 
-  return {
-    parseJwt,
-  }
+    return {
+        parseJwt,
+    }
 }