fix: add error boundary, safe base64 encoding, and proper fetch error handling

src/component/ErrorBoundary.jsx

@@ -0,0 +1,52 @@
+import React from 'react';
+
+const crashStyle = {
+    minHeight: '100vh',
+    display: 'flex',
+    alignItems: 'center',
+    justifyContent: 'center',
+    padding: '24px',
+    backgroundColor: 'var(--bg-primary)',
+    color: 'var(--text-primary)',
+    textAlign: 'center',
+};
+
+class ErrorBoundary extends React.Component {
+    constructor(props) {
+        super(props);
+        this.state = { hasError: false };
+    }
+
+    static getDerivedStateFromError() {
+        return { hasError: true };
+    }
+
+    render() {
+        const { hasError } = this.state;
+        const { children } = this.props;
+
+        if (hasError) {
+            return (
+                <div style={crashStyle}>
+                    <div>
+                        <h2 style={{ marginBottom: '8px' }}>Something went wrong</h2>
+                        <p style={{ marginBottom: '16px', opacity: 0.9 }}>
+                            The app hit an unexpected error. Reload to continue.
+                        </p>
+                        <button
+                            type="button"
+                            className="btn btn-primary"
+                            onClick={() => window.location.reload()}
+                        >
+                            Reload
+                        </button>
+                    </div>
+                </div>
+            );
+        }
+
+        return children;
+    }
+}
+
+export default ErrorBoundary;

src/graph-builder/local-storage-manager.js

@@ -1,5 +1,28 @@
 import { toast } from 'react-toastify';
 
+const encodeBase64 = (value) => {
+    const bytes = new TextEncoder().encode(value);
+    let binary = '';
+    bytes.forEach((byte) => {
+        binary += String.fromCharCode(byte);
+    });
+    return window.btoa(binary);
+};
+
+const decodeBase64 = (value) => {
+    const binary = window.atob(value);
+    const bytes = Uint8Array.from(binary, (char) => char.charCodeAt(0));
+    return new TextDecoder().decode(bytes);
+};
+
+const parseStoredJson = (raw) => {
+    try {
+        return JSON.parse(decodeBase64(raw));
+    } catch (e) {
+        return null;
+    }
+};
+
 const localStorageGet = (key) => {
     try {
         return window.localStorage.getItem(key);
@@ -27,11 +50,16 @@ const localStorageRemove = (key) => {
 
 const getSet = (ALL_GRAPHS) => {
     if (!localStorageGet(ALL_GRAPHS)) {
-        localStorageSet(ALL_GRAPHS, window.btoa(JSON.stringify([])));
+        localStorageSet(ALL_GRAPHS, encodeBase64(JSON.stringify([])));
     }
     const raw = localStorageGet(ALL_GRAPHS);
     if (!raw) return new Set();
-    return new Set(JSON.parse(window.atob(raw)));
+    const parsed = parseStoredJson(raw);
+    if (!Array.isArray(parsed)) {
+        localStorageSet(ALL_GRAPHS, encodeBase64(JSON.stringify([])));
+        return new Set();
+    }
+    return new Set(parsed);
 };
 
 const localStorageManager = {
@@ -41,24 +69,29 @@ const localStorageManager = {
     allgs: getSet(window.btoa('ALL_GRAPHS')),
 
     saveAllgs() {
-        localStorageSet(this.ALL_GRAPHS, window.btoa(JSON.stringify(Array.from(this.allgs))));
+        localStorageSet(this.ALL_GRAPHS, encodeBase64(JSON.stringify(Array.from(this.allgs))));
     },
 
     addEmptyIfNot() {
         if (!localStorageGet(this.ALL_GRAPHS)) {
-            localStorageSet(this.ALL_GRAPHS, window.btoa(JSON.stringify([])));
+            localStorageSet(this.ALL_GRAPHS, encodeBase64(JSON.stringify([])));
         }
     },
 
     get(id) {
         const raw = localStorageGet(id);
         if (raw === null) return null;
-        return JSON.parse(window.atob(raw));
+        const parsed = parseStoredJson(raw);
+        if (parsed === null) {
+            localStorageRemove(id);
+            return null;
+        }
+        return parsed;
     },
     save(id, graphContent) {
         this.addGraph(id);
         const serializedJson = JSON.stringify(graphContent);
-        localStorageSet(id, window.btoa(serializedJson));
+        localStorageSet(id, encodeBase64(serializedJson));
     },
     remove(id) {
         if (this.allgs.delete(id)) this.saveAllgs();
@@ -72,16 +105,25 @@ const localStorageManager = {
     getAllGraphs() {
         const raw = localStorageGet(this.ALL_GRAPHS);
         if (!raw) return [];
-        return JSON.parse(window.atob(raw));
+        const parsed = parseStoredJson(raw);
+        if (!Array.isArray(parsed)) {
+            localStorageSet(this.ALL_GRAPHS, encodeBase64(JSON.stringify([])));
+            return [];
+        }
+        return parsed;
     },
     addToFront(id) {
         if (this.allgs.has(id)) return;
         this.allgs.add(id);
         const raw = localStorageGet(this.ALL_GRAPHS);
         if (!raw) return;
-        const Garr = JSON.parse(window.atob(raw));
+        const Garr = parseStoredJson(raw);
+        if (!Array.isArray(Garr)) {
+            this.saveAllgs();
+            return;
+        }
         Garr.unshift(id);
-        localStorageSet(this.ALL_GRAPHS, window.btoa(JSON.stringify(Garr)));
+        localStorageSet(this.ALL_GRAPHS, encodeBase64(JSON.stringify(Garr)));
     },
     getAuthorName() {
         return localStorageGet(this.AUTHOR_NAME) || '';

src/index.jsx

@@ -2,12 +2,15 @@ import React from 'react';
 import ReactDOM from 'react-dom';
 import './index.css';
 import App from './App';
+import ErrorBoundary from './component/ErrorBoundary';
 import * as serviceWorkerRegistration from './serviceWorkerRegistration';
 import reportWebVitals from './reportWebVitals';
 
 ReactDOM.render(
     <React.StrictMode>
-        <App />
+        <ErrorBoundary>
+            <App />
+        </ErrorBoundary>
     </React.StrictMode>,
     document.getElementById('root'),
 );

src/serverCon/crud_http.js

@@ -1,18 +1,22 @@
 import ec from './config';
 
+function readTextOrThrow(x) {
+    return x.text().then((text) => {
+        if (x.ok) return text;
+        throw new Error(text || `Request failed with status ${x.status}`);
+    });
+}
+
 function getGraph(serverID) {
-    return fetch(`${ec.baseURL + ec.getGraph(serverID)}`).then((x) => x.text());
+    return fetch(`${ec.baseURL + ec.getGraph(serverID)}`).then((x) => readTextOrThrow(x));
 }
 
 function getGraphWithHashCheck(serverID, latestHash) {
     return fetch(`${ec.baseURL + ec.getGraph(serverID)}`, {
         headers: {
             'X-Latest-Hash': latestHash,
         },
-    }).then((x) => {
-        if (x.status === 200) return x.text();
-        return Promise.reject(x.text());
-    });
+    }).then((x) => readTextOrThrow(x));
 }
 
 function postGraph(graphml) {
@@ -22,10 +26,7 @@ function postGraph(graphml) {
         },
         method: 'POST',
         body: graphml,
-    }).then((x) => {
-        if (!x.ok) return Promise.reject(x.text());
-        return x.text();
-    });
+    }).then((x) => readTextOrThrow(x));
 }
 
 function updateGraph(serverID, graphml) {
@@ -35,10 +36,7 @@ function updateGraph(serverID, graphml) {
             'Content-Type': 'application/xml',
         },
         body: graphml,
-    }).then((x) => {
-        if (!x.ok) return Promise.reject(x.text());
-        return x.text();
-    });
+    }).then((x) => readTextOrThrow(x));
 }
 
 function forceUpdateGraph(serverID, graphml) {
@@ -48,10 +46,7 @@ function forceUpdateGraph(serverID, graphml) {
             'Content-Type': 'application/xml',
         },
         body: graphml,
-    }).then((x) => {
-        if (!x.ok) return Promise.reject(x.text());
-        return x.text();
-    });
+    }).then((x) => readTextOrThrow(x));
 }
 
 export {