minor reorg/cleanup

app/util/cacheDir.ts

@@ -0,0 +1,17 @@
+import RNFS from 'react-native-fs'
+import path from 'path'
+import { CacheItemTypeKey } from '@app/models/cache'
+
+const serversCacheDir = path.join(RNFS.ExternalDirectoryPath, 's')
+
+function cacheDir(serverId?: string, itemType?: CacheItemTypeKey, itemId?: string): string {
+  const segments: string[] = []
+
+  serverId && segments.push(serverId)
+  serverId && itemType && segments.push(itemType)
+  serverId && itemType && itemId && segments.push(itemId)
+
+  return path.join(serversCacheDir, ...segments)
+}
+
+export default cacheDir