refactor: derive SUPPORTED_IMAGE_EXTENSIONS from IMAGE_EXTENSION_TO_MIME

Author: brandonkachen

common/src/constants/images.ts

@@ -2,33 +2,6 @@
  * Image-related constants shared across the codebase
  */
 
-// Supported image formats for multimodal messages
-export const SUPPORTED_IMAGE_EXTENSIONS = new Set([
-  '.jpg',
-  '.jpeg',
-  '.png',
-  '.webp',
-  '.gif',
-  '.bmp',
-  '.tiff',
-  '.tif',
-])
-
-/**
- * Check if a file extension is a supported image format
- */
-export function isSupportedImageExtension(ext: string): boolean {
-  return SUPPORTED_IMAGE_EXTENSIONS.has(ext.toLowerCase())
-}
-
-/**
- * Image extensions as a regex alternation pattern (without dots)
- * e.g., "jpg|jpeg|png|webp|gif|bmp|tiff|tif"
- */
-export const IMAGE_EXTENSIONS_PATTERN = Array.from(SUPPORTED_IMAGE_EXTENSIONS)
-  .map((ext) => ext.slice(1)) // Remove leading dot
-  .join('|')
-
 /**
  * Extension to MIME type mapping for supported image formats
  */
@@ -43,13 +16,33 @@ export const IMAGE_EXTENSION_TO_MIME: Record<string, string> = {
   '.tif': 'image/tiff',
 }
 
+/**
+ * Supported image extensions (derived from IMAGE_EXTENSION_TO_MIME)
+ */
+export const SUPPORTED_IMAGE_EXTENSIONS = new Set(Object.keys(IMAGE_EXTENSION_TO_MIME))
+
+/**
+ * Check if a file extension is a supported image format
+ */
+export function isSupportedImageExtension(ext: string): boolean {
+  return SUPPORTED_IMAGE_EXTENSIONS.has(ext.toLowerCase())
+}
+
 /**
  * Get MIME type for an image extension
  */
 export function getImageMimeType(ext: string): string | null {
   return IMAGE_EXTENSION_TO_MIME[ext.toLowerCase()] ?? null
 }
 
+/**
+ * Image extensions as a regex alternation pattern (without dots)
+ * e.g., "jpg|jpeg|png|webp|gif|bmp|tiff|tif"
+ */
+export const IMAGE_EXTENSIONS_PATTERN = Object.keys(IMAGE_EXTENSION_TO_MIME)
+  .map((ext) => ext.slice(1)) // Remove leading dot
+  .join('|')
+
 // Size limits for image uploads
 // Research shows Claude/GPT-4V support up to 20MB, but we use practical limits
 // for good performance and token efficiency