Repo Structure Navigate

Schema Categories

• Primitives: string, number, boolean, bigint, date, symbol, blob, file
• Objects: object, strictObject, looseObject, objectWithRest
• Arrays: array, tuple, strictTuple, looseTuple, tupleWithRest
• Advanced: union, variant, intersect, record, map, set, lazy, custom
• Modifiers: optional, nullable, nullish, nonNullable, nonNullish, nonOptional

Action Types

Validation (return issues): email, url, uuid, regex, minLength, maxValue, check

Transformation (modify data): trim, toLowerCase, toUpperCase, mapItems, transform

Metadata: brand, flavor, metadata, description, title

File Naming Convention

Each schema/action/method has its own directory:

schemas/string/
├── string.ts        # Implementation
├── string.test.ts   # Runtime tests
├── string.test-d.ts # Type tests
└── index.ts         # Re-export

Core Patterns

Schemas define data types:

export interface StringSchema<TMessage> extends BaseSchema<...> {
  readonly kind: 'schema';
  readonly type: 'string';
  // ...
}

Actions validate/transform in pipelines:

export interface EmailAction<TInput, TMessage> extends BaseValidation<...> {
  readonly kind: 'validation';
  readonly type: 'email';
  // ...
}

Methods provide API functions:

export function parse<TSchema>(
  schema: TSchema,
  input: unknown
): InferOutput<TSchema>;

Key Types

• BaseSchema, BaseValidation, BaseTransformation - Base interfaces
• InferOutput<T>, InferInput<T>, InferIssue<T> - Type inference
• Config, ErrorMessage<T>, BaseIssue<T> - Configuration and errors
• '~standard' property - Standard Schema compatibility

Website (/website/src/routes/)

API Documentation

routes/api/
├── (schemas)/string/     # Schema docs
│   ├── index.mdx         # MDX content
│   └── properties.ts     # Type definitions
├── (actions)/email/      # Action docs
├── (methods)/parse/      # Method docs
├── (types)/StringSchema/ # Type docs
└── menu.md               # Navigation

Guides

routes/guides/
├── (get-started)/       # Intro, installation
├── (main-concepts)/     # Schemas, pipelines, parsing
├── (schemas)/           # Objects, arrays, unions
├── (advanced)/          # Async, i18n, JSON Schema
├── (migration)/         # Version upgrades
└── menu.md              # Navigation

Development

Playground

Use library/playground.ts for quick experimentation.

Adding a Schema/Action

1. Create directory: library/src/schemas/yourSchema/
2. Create files: yourSchema.ts, yourSchema.test.ts, yourSchema.test-d.ts, index.ts
3. Follow existing patterns (copy similar implementation)
4. Export from category index.ts
5. Run pnpm -C library test

Modifying Core Types

⚠️ Changes to library/src/types/ affect the entire library. Always run full test suite.

Quick Lookups

Commands

# Library
pnpm -C library build      # Build
pnpm -C library test       # Run tests
pnpm -C library lint       # Lint
pnpm -C library format     # Format

# Website
pnpm -C website dev        # Dev server
pnpm -C website build      # Production build

# Root
pnpm install               # Install all
pnpm format                # Format all

Key Principles

1. Modularity - Small, focused functions; one per file
2. Zero dependencies - Core library has no runtime deps
3. 100% test coverage - Required for library
4. Tree-shakable - Use // @__NO_SIDE_EFFECTS__ annotation
5. Type-safe - Full TypeScript with strict mode
6. ESM only - Imports include .ts extensions

Do's and Don'ts

Do:

• Follow existing code patterns
• Write runtime and type tests
• Add JSDoc documentation
• Keep functions small and focused
• Check bundle size impact

Don't:

• Add external dependencies
• Modify core types without full test run
• Skip tests
• Create large multi-purpose functions
• Modify generated files (dist/, coverage/)