TypeScript Boilerplate for Katas

A template for Coding Dojos, Katas, or starting a new TypeScript project.

Stack

Tool	Version	Role
TypeScript	6	Language + type checking
Vitest	4	Test runner + coverage
Biome	2	Linter + formatter
pnpm	11	Package manager

Requirements

• Node.js 24 LTS or later
• pnpm >= 11.7.0 — install with npm install -g pnpm or via corepack

Setup

pnpm install

Scripts

Command	What it does
pnpm test	Run all tests once (verbose)
pnpm run test:watch	Re-run tests on file changes
pnpm run test:coverage	Generate coverage report in coverage/
pnpm run build	Lint + type check (no output emitted)
pnpm run lint	Lint with Biome
pnpm run lint:fix	Lint and auto-fix
pnpm run format	Format all files with Biome
pnpm run check	Lint + format check together

Project structure

src/
  main.ts           # Starting point for your kata
  main.spec.ts      # Test file
  core/             # (optional) shared logic — importable as @core/*

Test files are picked up automatically if they match **/*.spec.ts or **/*.test.ts inside src/.

Path alias

The alias @core/* resolves to src/core/*. Use it for shared utilities:

import { something } from "@core/utils";

The src/core/ directory is not created by default — add it when you need it.

Notes and considerations

Module format

package.json has no "type" field, so Node.js treats all .ts files as CommonJS under module: nodenext. If you want ESM, add "type": "module" to package.json.

Type checking does not emit files

tsc --noEmit is used for type checking only. There is no build output. The build/ directory referenced in package.json is a leftover from the original boilerplate and is not used in this setup.

Vitest globals

describe, it, expect, and other Vitest globals are available in test files without explicit imports. This is configured via globals: true in vitest.config.ts and types: ["vitest/globals"] in tsconfig.json.

Biome linter rules

The linter is configured with preset: "none" — no rules are enabled by default. This is intentional to keep the template minimal. Enable rules as needed in biome.json:

"linter": {
  "enabled": true,
  "rules": {
    "preset": "recommended"
  }
}

Biome replaces ESLint and Prettier

There is no ESLint, no Prettier, and no .editorconfig. Biome handles both linting and formatting. Style is configured in biome.json (double quotes, 2-space indent, ES5 trailing commas).

pnpm run build runs lint first

The build script is biome lint . && tsc --noEmit. A lint error will prevent the type check from running.

Version pinning

All devDependencies are pinned to exact versions (no ^ or ~). Update intentionally:

pnpm update --latest