ArkType

ArkType is a type-first validation library where you write types that look like TypeScript syntax.

Installation

npm install arktype

Basic Schema

nuxt.config.ts

import { type } from 'arktype'

const runtimeConfigSchema = type({
  'public': {
    'apiBase': 'string',
    'appName?': 'string',
  },
  'databaseUrl': 'string',
  'secretKey': 'string',
  'port?': 'number',
})

export default defineNuxtConfig({
  modules: ['nuxt-safe-runtime-config'],

  runtimeConfig: {
    databaseUrl: process.env.DATABASE_URL || '',
    secretKey: process.env.SECRET_KEY || '',
    port: Number.parseInt(process.env.PORT || '3000'),
    public: {
      apiBase: process.env.NUXT_PUBLIC_API_BASE || 'https://api.example.com',
      appName: 'My App',
    },
  },

  safeRuntimeConfig: {
    $schema: runtimeConfigSchema,
  },
})

Common Patterns

Required vs Optional

type({
  required: 'string',           // must exist
  'optional?': 'string',        // can be undefined (note the ? in key)
  withDefault: 'number = 3000', // default value
})

String Validations

type({
  email: 'string.email',
  apiUrl: 'string.url',
  token: 'string >= 32',        // min length
  uuid: 'string.uuid',
})

Number Validations

type({
  port: 'integer & 1 <= number <= 65535',
  timeout: 'number >= 0',
  positive: 'number > 0',
})

Enums / Unions

type({
  environment: "'development' | 'staging' | 'production'",
  logLevel: "'debug' | 'info' | 'warn' | 'error'",
})

Nested Objects

type({
  public: {
    api: {
      baseUrl: 'string',
      version: 'string',
    },
  },
  redis: {
    host: 'string',
    port: 'number',
  },
})

Arrays

type({
  allowedOrigins: 'string[]',
  ports: 'number[]',
})

Full Example

nuxt.config.ts

import { type } from 'arktype'

const runtimeConfigSchema = type({
  'public': {
    'apiBase': 'string.url',
    'appName': 'string',
    'environment': "'development' | 'staging' | 'production'",
  },
  'database': {
    'url': 'string',
    'poolSize?': 'number',
  },
  'auth': {
    'jwtSecret': 'string >= 32',
    'sessionTtl': 'number > 0',
  },
  'email?': {
    'host': 'string',
    'port': 'integer > 0',
    'from': 'string.email',
  },
})

export default defineNuxtConfig({
  modules: ['nuxt-safe-runtime-config'],
  safeRuntimeConfig: { $schema: runtimeConfigSchema },
})

Note on Standard Schema

ArkType supports Standard Schema natively. The module automatically uses ArkType's ~standard interface for validation and JSON Schema generation.

Zod

Integrations