Vary number of decimals of file sizes

ts/components/Lightbox.tsx

@@ -775,10 +775,9 @@ export function Lightbox({
                       {attachment.totalDownloaded && attachment.size
                         ? i18n('icu:lightBoxDownloading', {
                             downloaded: formatFileSize(
-                              attachment.totalDownloaded,
-                              2
+                              attachment.totalDownloaded
                             ),
-                            total: formatFileSize(attachment.size, 2),
+                            total: formatFileSize(attachment.size),
                           })
                         : undefined}
                     </Toast>

ts/components/conversation/AttachmentDetailPill.tsx

@@ -126,7 +126,7 @@ export function AttachmentDetailPill({
       );
       text = (
         <div className="AttachmentDetailPill__text-wrapper">
-          {formatFileSize(totalSize, 2)}
+          {formatFileSize(totalSize)}
         </div>
       );
     } else if (totalDownloadedSize > 0) {
@@ -148,9 +148,9 @@ export function AttachmentDetailPill({
       text = (
         <div className="AttachmentDetailPill__text-wrapper">
           {totalDownloadedSize > 0 && areAnyPending
-            ? `${formatFileSize(totalDownloadedSize, 2)} / `
+            ? `${formatFileSize(totalDownloadedSize)} / `
             : undefined}
-          {formatFileSize(totalSize, 2)}
+          {formatFileSize(totalSize)}
         </div>
       );
     } else {
@@ -165,7 +165,7 @@ export function AttachmentDetailPill({
       );
       text = (
         <div className="AttachmentDetailPill__text-wrapper">
-          {formatFileSize(totalSize, 2)}
+          {formatFileSize(totalSize)}
         </div>
       );
     }
@@ -191,9 +191,9 @@ export function AttachmentDetailPill({
     <div className="AttachmentDetailPill">
       <div className="AttachmentDetailPill__text-wrapper">
         {totalDownloadedSize > 0 && areAnyPending
-          ? `${formatFileSize(totalDownloadedSize, 2)} / `
+          ? `${formatFileSize(totalDownloadedSize)} / `
           : undefined}
-        {formatFileSize(totalSize, 2)}
+        {formatFileSize(totalSize)}
         {isGif ? ' · GIF' : undefined}
       </div>
     </div>

ts/util/formatFileSize.ts

@@ -2,6 +2,9 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 import filesize from 'filesize';
 
-export function formatFileSize(size: number, decimals = 0): string {
-  return filesize(size, { round: decimals });
+// Intentional, `filesize` uses `jedec` standard by default
+const MB = 1000 * 1000;
+
+export function formatFileSize(size: number): string {
+  return filesize(size, { round: size < MB ? 0 : 1 });
 }