fix#3521

Generated PR message below

Problem

Island files named after JavaScript global objects (e.g., Map.tsx,Set.tsx,Promise.tsx) cause runtime errors. WhenUniqueNamer generates identifiers from these filenames, the resulting variable names shadow global constructors, breaking instantiation:

importMapfrom"/islands/Map.tsx";boot({Map},props);// Map resolves to global constructor, not the island

This results inTypeError: Map is not a constructor when the framework attempts to usenew Map() internally.

Solution

Added JavaScript global objects to theJS_RESERVED set inUniqueNamer. Names matching reserved keywords or globals are now automatically prefixed with underscore:

import_Map_1from"/islands/Map.tsx";boot({_Map_1},props);// No shadowing

Changes

• utils.ts: ExtendedJS_RESERVED with:

  • JavaScript built-ins (Map, Set, Array, Promise, Object, etc.)
  • Web APIs (fetch, console, URL, WebSocket, etc.)
  • Deno-specific globals (Deno namespace)
  • Node.js compatibility globals (process, Buffer, global)

• Integration tests: Added test cases for both Builder and Vite build systems verifying islands named after globals work correctly

Impact

Single-location fix inUniqueNamer applies to all code generation (islands, routes, etc.). Island names are prefixed when needed, preserving debuggability while preventing shadowing bugs.