Apply suggestions from code review

Co-authored-by: Aron Carroll <[email protected]>

Author: mattt

index.d.ts

@@ -46,7 +46,7 @@ declare module "replicate" {
     size: number;
     etag: string;
     checksum: string;
-    metadata: Record<string, any>;
+    metadata: Record<string, unknown>;
     created_at: string;
     expires_at: string | null;
     urls: {

lib/files.js

@@ -11,13 +11,13 @@ async function createFile(file, metadata = {}) {
   let filename;
   let blob;
   if (file instanceof Blob) {
-    fileName = file.name || `blob_${Date.now()}`;
+    filename = file.name || `blob_${Date.now()}`;
     blob = file;
   } else if (Buffer.isBuffer(file)) {
-    fileName = `buffer_${Date.now()}`;
+    filename = `buffer_${Date.now()}`;
     blob = new Blob(file, { type: "application/octet-stream" });
   } else {
-    throw new Error("Invalid file argument, must be a Blob or File");
+    throw new Error("Invalid file argument, must be a Blob, File or Buffer");
   }
 
   form.append("content", blob, filename);