Add meme-adding logic

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

src/utilities/filesystem.ts

@@ -0,0 +1,33 @@
+import { MEME_TYPE } from '../database';
+
+const allowedImageMimeTypes = [
+  'image/bmp',
+  'image/jpeg',
+  'image/png',
+  'image/webp',
+];
+
+const allowedGifMimeTypes = ['image/gif'];
+
+const allowedMimeTypes = [...allowedImageMimeTypes, ...allowedGifMimeTypes];
+
+const getMemeType = (mimeType: string) => {
+  switch (mimeType) {
+    case 'image/bmp':
+    case 'image/jpeg':
+    case 'image/png':
+    case 'image/webp': {
+      return MEME_TYPE.IMAGE;
+    }
+    case 'image/gif': {
+      return MEME_TYPE.GIF;
+    }
+  }
+};
+
+export {
+  allowedImageMimeTypes,
+  allowedGifMimeTypes,
+  allowedMimeTypes,
+  getMemeType,
+};