fix(frontend): add fallback for DOMPurify in Cloudflare Workers

apps/frontend/src/lib/sanitize.ts

@@ -4,37 +4,61 @@
  */
 import DOMPurify from 'isomorphic-dompurify'
 
+/**
+ * Basic SVG sanitization for environments without DOM
+ * Removes dangerous tags and attributes
+ */
+const basicSanitize = (svg: string): string => {
+  // Remove script tags and their content
+  let sanitized = svg.replace(/<script\b[^<]*(?:(?!<\/script>)<[^<]*)*<\/script>/gi, '')
+  // Remove dangerous attributes
+  sanitized = sanitized.replace(/\s*on\w+\s*=\s*["'][^"']*["']/gi, '')
+  // Remove other dangerous tags
+  sanitized = sanitized.replace(/<(iframe|object|embed|style)[^>]*>.*?<\/\1>/gi, '')
+  return sanitized
+}
+
 /**
  * Sanitize SVG content to prevent XSS attacks
  * Only allows safe SVG elements and attributes
  */
 export const sanitizeSvg = (svg: string): string => {
-  return DOMPurify.sanitize(svg, {
-    USE_PROFILES: { svg: true, svgFilters: true },
-    ADD_TAGS: ['use', 'defs', 'symbol'],
-    ADD_ATTR: [
-      'viewBox',
-      'fill',
-      'class',
-      'stroke',
-      'stroke-width',
-      'd',
-      'cx',
-      'cy',
-      'r',
-      'x',
-      'y',
-      'width',
-      'height',
-      'transform',
-      'xmlns',
-      'xmlns:xlink',
-      'xlink:href',
-      'preserveAspectRatio',
-      'clip-rule',
-      'fill-rule',
-    ],
-    FORBID_TAGS: ['script', 'iframe', 'object', 'embed', 'style'],
-    FORBID_ATTR: ['onload', 'onerror', 'onclick', 'onmouseover'],
-  })
+  // Check if DOMPurify is available (has sanitize method)
+  if (typeof DOMPurify?.sanitize === 'function') {
+    try {
+      return DOMPurify.sanitize(svg, {
+        USE_PROFILES: { svg: true, svgFilters: true },
+        ADD_TAGS: ['use', 'defs', 'symbol'],
+        ADD_ATTR: [
+          'viewBox',
+          'fill',
+          'class',
+          'stroke',
+          'stroke-width',
+          'd',
+          'cx',
+          'cy',
+          'r',
+          'x',
+          'y',
+          'width',
+          'height',
+          'transform',
+          'xmlns',
+          'xmlns:xlink',
+          'xlink:href',
+          'preserveAspectRatio',
+          'clip-rule',
+          'fill-rule',
+        ],
+        FORBID_TAGS: ['script', 'iframe', 'object', 'embed', 'style'],
+        FORBID_ATTR: ['onload', 'onerror', 'onclick', 'onmouseover'],
+      })
+    } catch {
+      // Fallback to basic sanitization if DOMPurify fails
+      return basicSanitize(svg)
+    }
+  }
+  // Fallback for non-browser environments (Cloudflare Workers)
+  return basicSanitize(svg)
 }