TypeScript

Zeno uses the @zeno-lib/typescript package to share strict TypeScript configurations across all packages and apps.

You don't have to set tsconfig.json options such as moduleResolution, jsx, lib, strict, Next.js include globs or the Next.js plugin by hand. Extend one config and it sets them for you.

Available configsCopy Anchor Link

The configs form an inheritance chain. Each level extends the previous one:

UsageCopy Anchor Link

Extend the appropriate config in your package's tsconfig.json:

{
  "extends": "@zeno-lib/typescript/nextjs.json"
}

You don't need to set compilerOptions, include or exclude. The config handles module resolution, strict checks, JSX, the DOM libs and the Next.js includes.

Which config to useCopy Anchor Link

Examples in the repoCopy Anchor Link

What's includedCopy Anchor Link

Base configCopy Anchor Link

Every config inherits these settings:

• Bundler module resolution: resolves imports the way bundlers such as Vite, Turbopack and webpack do
• ESNext modules with verbatimModuleSyntax: TypeScript drops imports marked type and leaves every other import and export as written
• JSON imports: resolveJsonModule is on
• Incremental builds: TypeScript reuses the previous run's results, so rechecks are faster
• Isolated modules: every file must compile on its own, as SWC and esbuild require
• No emit: TypeScript only type-checks, and bundlers produce the output

Strictest configCopy Anchor Link

Adds these checks on top of strict: true:

• noFallthroughCasesInSwitch: prevents fallthrough in switch statements
• noImplicitOverride: requires the override keyword
• noImplicitReturns: every code path must return
• noUnusedLocals: no unused local variables
• noUnusedParameters: no unused function parameters
• noUncheckedIndexedAccess: indexed access returns T | undefined
• allowUnreachableCode: false: unreachable code is an error
• allowUnusedLabels: false: unused labels are an error

Next.js configCopy Anchor Link

On top of the React config, the Next.js config:

• Registers the next TypeScript plugin for App Router type safety
• Includes next-env.d.ts and .next/types/**/*.ts for generated types
• Includes every *.ts and *.tsx file under the project root

Type checkingCopy Anchor Link

Run type checking across all packages:

pnpm types:check

Or for a specific package:

pnpm turbo run types:check --filter @zeno-lib/ui