How does 'Module Detection' affect global vs module scoping in modern TS?

Module detection determines if a file is treated as a global script or an isolated module, affecting how top-level declarations are shared.

By default, files without 'import' or 'export' are treated as global scripts, meaning variables can leak across files and cause collisions. TS 4.7+ introduced 'moduleDetection: force', which ensures every file is treated as a module. This is critical in modern ESM-focused architectures to ensure that files remain isolated even if they don't explicitly export anything.