fix(ui): move attachment sizes to MB when rounding reaches 1024 KB

ui/src/api/chat/attachments.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { MAX_TOTAL_BYTES, isAllowedFile, mediaTypeOf, stageFiles, textLinks } from "./attachments";
+import { MAX_TOTAL_BYTES, formatBytes, isAllowedFile, mediaTypeOf, stageFiles, textLinks } from "./attachments";
 
 const sized = (name: string, type: string, size: number) =>
   ({ name, type, size }) as File;
@@ -103,3 +103,19 @@ describe("stageFiles", () => {
     expect(stageFiles([], [sized("a.md", "", 10)]).error).toBeUndefined();
   });
 });
+
+describe("formatBytes", () => {
+  it.each([
+    [0, "0 B"],
+    [1023, "1023 B"],
+    [1024, "1 KB"],
+    [1536, "1.5 KB"],
+    [1048524, "1023.9 KB"],
+    [1048525, "1 MB"],
+    [1048575, "1 MB"],
+    [1048576, "1 MB"],
+    [5 * 1024 * 1024, "5 MB"],
+  ])("formats %d bytes as %s", (bytes, expected) => {
+    expect(formatBytes(bytes)).toBe(expected);
+  });
+});

ui/src/api/chat/attachments.ts

@@ -118,7 +118,10 @@ export function fileNameFromUrl(url: string): string {
 
 export function formatBytes(bytes: number): string {
   if (bytes < 1024) return `${bytes} B`;
-  if (bytes < 1024 * 1024) return `${Number((bytes / 1024).toFixed(1))} KB`;
+  // Pick the unit after rounding: 1,048,525 bytes is 1023.95 KB, which
+  // rounds to "1024 KB" and should read as 1 MB.
+  const kb = Number((bytes / 1024).toFixed(1));
+  if (kb < 1024) return `${kb} KB`;
   return `${Number((bytes / (1024 * 1024)).toFixed(1))} MB`;
 }