tsconfig.json Generator

What this tool is used for

• Starting a project with a config that matches its runtime rather than copying one from another repo.
• Comparing a strict preset against your current settings to see what you are not enforcing.
• Producing a config for a Node service where the module and target settings differ from a browser app.
• Generating a baseline before adding project references or path aliases by hand.
• Checking which options a framework actually requires versus which are conventional.

Frequently Asked Questions

What does strict actually turn on?

Eight flags at once — `noImplicitAny`, `strictNullChecks`, `strictFunctionTypes`, `strictBindCallApply`, `strictPropertyInitialization`, `noImplicitThis`, `useUnknownInCatchVariables` and `alwaysStrict`. `strictNullChecks` is the one that catches the most real bugs and the one that hurts most to enable late.

Which target and lib should I set?

`target` decides the syntax emitted and `lib` decides which APIs the type checker knows about. Setting a modern target with a stale lib is the mismatch that produces "Property 'at' does not exist on type 'Array'" while the code runs fine.

What is moduleResolution bundler for?

Matching how Vite, esbuild and similar tools actually resolve — extensionless imports, `exports` maps, no requirement for `.js` suffixes. `node16` and `nodenext` enforce Node's real rules instead, which is stricter and correct when Node is the runtime.

Does TypeScript check the emitted JavaScript?

No — types are erased and nothing is enforced at runtime. Data crossing a boundary — an API response, a JSON file, form input — is typed by assertion rather than by verification, which is why runtime validation is a separate concern that types cannot cover.

Should I enable noUncheckedIndexedAccess?

It is the most valuable flag outside `strict`, and the most disruptive. It makes `arr[0]` return `T | undefined`, which is the truth — but it surfaces hundreds of errors in an existing codebase, so it is far easier adopted at the start than retrofitted.

Common errors and gotchas

• Enabling every strict flag on an existing codebase at once, which buries real problems in hundreds of errors.
• Setting a target the runtime does not support, which compiles cleanly and fails at run time.
• Mismatching module and moduleResolution, which produces import errors that look like missing packages.
• Copying a browser config into a Node project, where the lib and types settings are wrong.
• Expecting the compiler to bundle. It type-checks and emits; bundling is a separate tool's job.