The shared compiler preset hierarchy, intended consumers, local configuration responsibilities, and verification impact.
Every preset extends base.json, which owns strict mode, library-check policy,
and consistent file-name casing. Workspaces select the closest runtime preset
and add only local paths, files, generated types, output directories, or test
runner types.
| Preset | Intended environment and important choices |
|---|---|
library | ES2020 library output with bundler resolution and JSON modules |
nextjs | DOM, React JSX, Next plugin, Bun types, no emit, incremental |
react-library | Next-compatible JSX without JavaScript or Next plugin state |
tooling | no-emit ESNext scripts and configuration executed by Bun |
worker | ESNext modules, isolated bundler compilation, Cloudflare types |
bun | preserved modules, ESNext library, forced module detection, Bun types |
Production configurations exclude test-only source where a workspace has a
separate tsconfig.test.json. That test configuration adds runner globals,
fixtures, or aliases without leaking them into production compilation.
Do not add Node, DOM, Bun, or Cloudflare globals to base; choose the owning
runtime preset or a local override. Before changing a preset, search every
extends consumer and run both production and test typechecks where declared.
A configuration package with no local test command is not verified merely by
parsing its JSON—the consumer matrix is its effective test surface.
