fix: keep the text typed in quick reply when opening the full composer

src/lib/__tests__/reply-compose.test.ts

@@ -0,0 +1,29 @@
+import { describe, it, expect } from 'vitest';
+import type { Email } from '../../api/types';
+import { replyComposeParams } from '../reply-compose';
+
+const source = {
+  id: 'm1',
+  threadId: 't1',
+  mailboxIds: {},
+  keywords: {},
+  size: 1,
+  receivedAt: '2026-10-14T10:00:00Z',
+  subject: 'Hello',
+  from: [{ name: 'Petra', email: 'petra@example.net' }],
+  textBody: [{ partId: '1', type: 'text/plain' }],
+  bodyValues: { 1: { value: 'Please confirm.' } },
+} as unknown as Email;
+
+describe('replyComposeParams', () => {
+  it('carries the text typed in quick reply into the composer', () => {
+    const params = replyComposeParams('reply', source, undefined, 'Got it, thanks!');
+    expect(params?.prefillBody).toBe('Got it, thanks!');
+    expect(params?.replyTo?.from.email).toBe('petra@example.net');
+  });
+
+  it('adds nothing when nothing was typed', () => {
+    expect(replyComposeParams('reply', source)?.prefillBody).toBeUndefined();
+    expect(replyComposeParams('reply', source, undefined, '   ')?.prefillBody).toBeUndefined();
+  });
+});

src/lib/reply-compose.ts

@@ -5,12 +5,15 @@ import { pickEmailBody, plainTextBody } from './email-body';
 /**
  * Composer params for a reply / reply-all / forward of `source`. Shared by
  * the thread viewer and the `mail/message/<id>?action=reply` deep link (the
- * triage widget). Null when there is nobody to reply to.
+ * triage widget). Null when there is nobody to reply to. `typed` is text
+ * the user already wrote (quick reply's "More options"); it goes above the
+ * quote.
  */
 export function replyComposeParams(
   mode: 'reply' | 'replyAll' | 'forward',
   source: Email,
   ownerAccountId?: string,
+  typed?: string,
 ): NonNullable<RootStackParamList['Compose']> | null {
   const from = source.from?.[0];
   if (!from && mode !== 'forward') return null;
@@ -24,6 +27,7 @@ export function replyComposeParams(
   const body = !quoteHtml || picked.text ? plainTextBody(source) : undefined;
   return {
     mode,
+    ...(typed?.trim() ? { prefillBody: typed } : null),
     replyTo: {
       from: from ?? { email: '' },
       to: source.to,

src/screens/EmailThreadScreen.tsx

@@ -557,10 +557,10 @@ function EmailViewer({ route, navigation, embedded = false, onActiveChange }: Pr
   };
 
   // Reply / forward the given message (a thread card's own, or the active one).
-  const navigateCompose = React.useCallback((mode: 'reply' | 'replyAll' | 'forward', target?: Email) => {
+  const navigateCompose = React.useCallback((mode: 'reply' | 'replyAll' | 'forward', target?: Email, typed?: string) => {
     const source = target ?? email;
     if (!source) return;
-    const params = replyComposeParams(mode, source, ownerAccountId);
+    const params = replyComposeParams(mode, source, ownerAccountId, typed);
     if (params) navigation.navigate('Compose', params);
   }, [email, navigation, ownerAccountId]);
 
@@ -961,7 +961,7 @@ interface EmailPaneProps {
   onToggleStar: (email: Email) => void;
   onAddressPress: (address: EmailAddress) => void;
   onEmailPatched: (email: Email) => void;
-  onReply: (mode: 'reply' | 'replyAll' | 'forward', email: Email) => void;
+  onReply: (mode: 'reply' | 'replyAll' | 'forward', email: Email, typed?: string) => void;
   onSwipe: (direction: 'prev' | 'next') => void;
   onZoomChange: (zoom: { pinching: boolean; zoomed: boolean }) => void;
 }
@@ -1182,7 +1182,8 @@ function EmailPane({
           <QuickReplyBox
             email={newest}
             jmapAccountId={jmapAccountId}
-            onMoreOptions={() => onReply('reply', newest)}
+            // The text typed so far moves into the full composer.
+            onMoreOptions={(draft) => onReply('reply', newest, draft)}
             onSent={onEmailPatched}
             onFocus={handleQuickReplyFocus}
             onBlur={handleQuickReplyBlur}