@projectplaceholders/typescript-config

Strict TypeScript presets for AI-assisted codebases.

A loose compiler lets an agent's plausible-looking code through. A strict one turns the compiler into the reviewer that reads every diff before you do — which is the whole point.

Presets

| Preset | Extends | For | |---|---|---| | base.json | — | Shared strictness. NodeNext module resolution. | | next.json | base | Next.js apps. ESNext + Bundler, jsx: preserve, noEmit. | | node.json | base | CLIs, services, tooling. No DOM lib, @types/node. | | react-library.json | base | React component libraries consumed through a bundler. ESNext + Bundler, jsx: react-jsx. |

// tsconfig.json
{
  "extends": "@projectplaceholders/typescript-config/next.json"
}

What every preset guarantees

| Flag | Catches | |---|---| | strict | Implicit any, unsound this, unchecked nulls | | noUncheckedIndexedAccess | arr[0] treated as always present | | exactOptionalPropertyTypes | { a: undefined } passed where a?: string is declared | | noImplicitOverride | A subclass silently shadowing a base method | | noFallthroughCasesInSwitch | A case that runs into the next one | | verbatimModuleSyntax | Type-only imports that survive into runtime code | | erasableSyntaxOnly | enum, namespace, parameter properties — syntax that needs a real transform |

These are enforced, not documented: test/strict-flags.test.mjs typechecks a fixture with one deliberate violation per flag and asserts every preset still reports it. Weaken a flag and the test names it.

pnpm test