TypeScript Migration Fixes

Error: timerStopf instead of timerStop File: frontend/chatterApp.js line 86 Fix: Changed stopTimer as timerStopf to stopTimer as timerStop

Error: coreEnsureMessagePersisted and coreSendMessage not exported Fix:

• Replaced coreEnsureMessagePersisted with corePersistMessageAtIndex
• Inlined the legacy coreSendMessage implementation directly in sendMessage()

Error: Browser can't parse export type { ... } File: frontend/core/index.ts Fix: Removed export type { AppState, DexieDatabase } line

Error: Server serving .ts files as text/plain instead of application/javascript File: backend/routes/static.js Fix: Added TypeScript transpilation using Deno's emit module

if (rel.endsWith('.ts')) {
  const { transpile } = await import('https://deno.land/x/emit@0.31.0/mod.ts');
  const result = await transpile(new URL(`file://${Deno.cwd()}/${rel}`));
  body = result.get(new URL(`file://${Deno.cwd()}/${rel}`).href) || body;
  contentType = 'application/javascript; charset=utf-8';
}

Error: Functions declared twice in types.ts Fix: Removed duplicate declarations:

• messageToUIMessage (was on lines 333 and 395)
• createDefaultSessionTree (was on lines 263 and 395)

Browsers only understand JavaScript, not TypeScript. TypeScript features like:

• import type { ... } - Type-only imports
• interface declarations
• type aliases
• Type annotations (: string, : number, etc.)
• export type

All of these cause syntax errors in browsers.

The server now transpiles TypeScript to JavaScript on-the-fly:

1. Browser requests .ts file
2. Server reads the TypeScript source
3. Server uses Deno's emit module to transpile it
4. Server serves the transpiled JavaScript (with all TypeScript syntax removed)
5. Browser runs pure JavaScript

1. backend/routes/static.js - Added TypeScript transpilation
2. frontend/chatterApp.js - Fixed import typos and missing functions
3. frontend/core/index.ts - Removed export type
4. frontend/types.ts - Removed duplicate function declarations

• App loads without errors
• Create new chat works
• Send message works
• Reasoning displays
• Branch switching works
• Fork functionality works
• Refresh preserves data

TypeScript transpilation happens on every request. For production, consider:

1. Pre-compiling TypeScript to JavaScript
2. Caching transpiled results
3. Using a build step to generate .js files

For development, the current on-the-fly transpilation works fine.