arktype-validation — Skillopedia

ArkType Validation Overview ArkType is a TypeScript-native runtime validation library that defines schemas using string expressions mirroring TypeScript syntax, providing editor autocomplete, syntax highlighting, and optimized validators. Use when building type-safe APIs, validating JSON payloads, or replacing Zod with a more TypeScript-idiomatic approach. Not suitable for projects that need Zod ecosystem compatibility or JSON Schema output. Package: Quick Reference | Pattern | Usage | | --------------------------------- | ----------------------------------------------- | | | Define object sc…

);\n// Regex\u003c`${bigint}.${bigint}.${bigint}`, { captures: [...] }>\n\nconst email = regex('^(?\u003cname>\\\\w+)@(?\u003cdomain>\\\\w+\\\\.\\\\w+)

Important: agents should read /llm.txt, /llms.txt, or /.well-known/skills.json to discover the public Skillopedia API.

);\n// Named capture groups are typed\n```\n\nFor most validation, ArkType's built-in `string.email`, `string.semver`, or inline `/regex/` syntax is sufficient. Use `arkregex` when you need typed capture groups or compile-time string type inference.\n","content_type":"text/markdown; charset=utf-8","language":"markdown","size":6496,"content_sha256":"e289e894e7337bc86e803e65c598a77533625e2a8c8afd2d82ea338fb2a10904"},{"filename":"references/schema-types.md","content":"---\ntitle: Schema Types\ndescription: ArkType primitives, string keywords, number constraints, objects with optional and default properties, arrays, tuples, unions, literals, regex patterns, and inline constraints\ntags:\n [\n type,\n string,\n number,\n boolean,\n object,\n array,\n tuple,\n union,\n literal,\n optional,\n default,\n constraints,\n regex,\n email,\n url,\n uuid,\n semver,\n integer,\n ]\n---\n\n# Schema Types\n\n## Primitives\n\nArkType supports both string syntax and fluent API:\n\n```ts\nimport { type } from 'arktype';\n\n// String syntax\nconst str = type('string');\nconst num = type('number');\nconst bool = type('boolean');\nconst bigint = type('bigint');\nconst sym = type('symbol');\nconst date = type('Date');\n\n// Fluent API\nconst str2 = type.string;\nconst num2 = type.number;\nconst bool2 = type.boolean;\n```\n\n## String Keywords\n\nBuilt-in string format validators:\n\n```ts\n// Validators (return string)\ntype('string.email');\ntype('string.url');\ntype('string.uuid');\ntype('string.uuid.v4');\ntype('string.semver');\ntype('string.ip');\ntype('string.ip.v4');\ntype('string.ip.v6');\ntype('string.date');\ntype('string.date.iso');\ntype('string.numeric');\ntype('string.integer');\ntype('string.alpha');\ntype('string.alphanumeric');\ntype('string.digits');\ntype('string.hex');\ntype('string.creditCard');\ntype('string.base64');\ntype('string.base64.url');\ntype('string.json');\ntype('string.host'); // Hostname (IP or domain)\n\n// Morphs (transform the value)\ntype('string.trim'); // Trims whitespace\ntype('string.lower'); // Transforms to lowercase\ntype('string.upper'); // Transforms to uppercase\ntype('string.capitalize'); // Capitalizes first letter\ntype('string.normalize.NFC'); // Unicode normalization\ntype('string.json.parse'); // Parses JSON string at runtime\ntype('string.numeric.parse'); // Parses numeric string to number\ntype('string.integer.parse'); // Parses integer string to number\ntype('string.date.parse'); // Parses date string to Date\ntype('string.date.iso.parse'); // Parses ISO date string to Date\ntype('string.url.parse'); // Parses URL string to URL instance\n```\n\n## String Constraints\n\n```ts\ntype('string >= 1'); // Min length 1\ntype('string \u003c= 100'); // Max length 100\ntype('string >= 1 & string \u003c= 100'); // Range (intersection)\ntype('5 \u003c= string \u003c= 20'); // Range (compact syntax)\ntype('string == 5'); // Exact length\n\n// Regex patterns\ntype('/^[a-z]+$/');\ntype({ key: /^[a-z]+$/ }); // RegExp object\n```\n\n## Number Constraints\n\n```ts\ntype('number > 0'); // Positive\ntype('number >= 0'); // Non-negative\ntype('number \u003c 100'); // Less than 100\ntype('number % 2'); // Divisible by 2 (even)\ntype('number.integer'); // Integer only\ntype('number.safe'); // Safe integer range\ntype('number.epoch'); // Unix timestamp (safe integer >= 0)\ntype('number.port'); // Valid port (integer 0-65535)\ntype('number > 0 & number \u003c 100'); // Range (intersection)\ntype('0 \u003c= number \u003c= 100'); // Range (compact syntax)\ntype('1 \u003c= number.integer \u003c= 5'); // Constrained range\ntype('0 \u003c= number.integer % 5 \u003c= 100'); // Range + divisibility\n\n// Fluent API constraints\ntype.number.atLeast(0);\ntype.number.atMost(100);\ntype.number.moreThan(0);\ntype.number.lessThan(100);\ntype.number.divisibleBy(5);\n```\n\n## Objects\n\n```ts\nconst User = type({\n name: 'string',\n email: 'string.email',\n age: 'number >= 0',\n});\n\n// Infer TypeScript type\ntype User = typeof User.infer;\n// { name: string; email: string; age: number }\n```\n\n### Optional Properties\n\n```ts\nconst User = type({\n name: 'string',\n 'bio?': 'string', // Optional (question mark on key)\n 'age?': 'number',\n});\n```\n\n### Default Values\n\n```ts\nconst Config = type({\n 'theme = \"light\"': 'string',\n 'retries = 3': 'number',\n 'debug = false': 'boolean',\n});\n```\n\n### Undeclared Key Handling\n\n```ts\n// Inline syntax with \"+\"\nconst Strict = type({\n '+': 'reject',\n name: 'string',\n});\n\n// Fluent API\nconst StrictFluent = type({\n name: 'string',\n}).onUndeclaredKey('reject'); // Reject extra keys\n\nconst Strip = type({\n name: 'string',\n}).onUndeclaredKey('delete'); // Strip extra keys\n\n// Deep undeclared key handling (nested objects)\nconst DeepStrip = type({\n name: 'string',\n nested: {\n preserved: 'string',\n },\n}).onDeepUndeclaredKey('delete');\n```\n\n### Object Modifiers\n\n```ts\nconst User = type({\n name: 'string',\n email: 'string.email',\n 'age?': 'number',\n});\n\nUser.pick('name', 'email'); // Only name and email\nUser.omit('age'); // Remove age\nUser.merge({\n role: \"'admin' | 'user'\",\n});\n```\n\n## Arrays and Tuples\n\n```ts\n// Arrays\ntype('string[]');\ntype('number[]');\ntype('string.email[]');\n\n// In objects\nconst Team = type({\n members: 'string[]',\n scores: 'number[]',\n});\n\n// Tuples\ntype(['string', 'number']); // [string, number]\ntype(['string', 'number', '...', 'boolean[]']); // [string, number, ...boolean[]]\n```\n\n## Unions and Literals\n\n```ts\n// Unions\ntype('string | number');\ntype(\"'success' | 'error' | 'pending'\");\n\n// Literal values\ntype('true');\ntype('false');\ntype('0');\ntype(\"'active'\");\n\n// In objects\nconst Event = type({\n type: \"'click' | 'hover' | 'focus'\",\n target: 'string',\n 'data?': 'unknown',\n});\n```\n\n## Intersections\n\n```ts\n// Combine constraints\ntype('number > 0 & number \u003c 100 & number.integer');\ntype('string >= 1 & string \u003c= 50');\n\n// Object intersections\nconst Named = type({ name: 'string' });\nconst Aged = type({ age: 'number' });\nconst Person = Named.and(Aged);\n```\n\n## Date Constraints\n\n```ts\n// String syntax with date literals\nconst Bounded = type({\n dateInThePast: `Date \u003c ${Date.now()}`,\n dateAfter2000: \"Date > d'2000-01-01'\",\n dateAtOrAfter1970: 'Date >= 0',\n});\n\n// Fluent API\nconst FluentBounded = type({\n dateInThePast: type.Date.earlierThan(Date.now()),\n dateAfter2000: type.Date.laterThan('2000-01-01'),\n dateAtOrAfter1970: type.Date.atOrAfter(0),\n});\n```\n\n## Index Signatures and keyof\n\n```ts\n// Index signatures\ntype('Record\u003cstring, unknown>');\nconst Dict = type({ '[string]': 'number' });\n\n// Extract object keys as union type\nconst User = type({\n name: 'string',\n email: 'string.email',\n});\n\nconst UserKey = User.keyof();\ntype UserKey = typeof UserKey.infer; // \"name\" | \"email\"\n```\n\n## Special Types\n\n```ts\ntype('unknown'); // Any value\ntype('never'); // No value\ntype('void'); // undefined\ntype('null');\ntype('undefined');\ntype('object'); // Non-null object\ntype('Record\u003cstring, unknown>'); // String-keyed object\n```\n","content_type":"text/markdown; charset=utf-8","language":"markdown","size":6388,"content_sha256":"ad27049ca212a8c6e53db8c37e0aee23fa0c0f6076a9ea3b50a59d2b6b96f9f0"}],"content_json":{"type":"doc","content":[{"type":"heading","attrs":{"level":1},"content":[{"text":"ArkType Validation","type":"text"}]},{"type":"heading","attrs":{"level":2},"content":[{"text":"Overview","type":"text"}]},{"type":"paragraph","content":[{"text":"ArkType is a TypeScript-native runtime validation library that defines schemas using string expressions mirroring TypeScript syntax, providing editor autocomplete, syntax highlighting, and optimized validators. 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Important: agents should read /llm.txt, /llms.txt, or /.well-known/skills.json to discover the public Skillopedia API.