TypeBox

JSON Schema Type Builder with Static Type Resolution for TypeScript



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Install

Npm

$ npm install @sinclair/typebox --save

Deno

import { Static, Type } from 'npm:@sinclair/typebox'

Esm

import { Static, Type } from 'https://esm.sh/@sinclair/typebox'

Example

import { Static, Type } from '@sinclair/typebox'

const T = Type.Object({                              // const T = {
  x: Type.Number(),                                  //   type: 'object',
  y: Type.Number(),                                  //   required: ['x', 'y', 'z'],
  z: Type.Number()                                   //   properties: {
})                                                   //     x: { type: 'number' },
                                                     //     y: { type: 'number' },
                                                     //     z: { type: 'number' }
                                                     //   }
                                                     // }

type T = Static<typeof T>                            // type T = {
                                                     //   x: number,
                                                     //   y: number,
                                                     //   z: number
                                                     // }

Overview

TypeBox is a runtime type builder that creates in-memory JSON Schema objects that can be statically inferred as TypeScript types. The schemas produced by this library are designed to match the static type assertion rules of the TypeScript compiler. TypeBox enables one to create a unified type that can be statically checked by TypeScript and runtime asserted using standard JSON Schema validation.

This library is designed to enable JSON schema to compose with the same flexibility as TypeScript’s type system. It can be used as a simple tool to build up complex schemas or integrated into REST or RPC services to help validate data received over the wire.

License MIT

Contents

Usage

The following shows general usage.

import { Static, Type } from '@sinclair/typebox'

//--------------------------------------------------------------------------------------------
//
// Let's say you have the following type ...
//
//--------------------------------------------------------------------------------------------

type T = {
  id: string,
  name: string,
  timestamp: number
}

//--------------------------------------------------------------------------------------------
//
// ... you can express this type in the following way.
//
//--------------------------------------------------------------------------------------------

const T = Type.Object({                              // const T = {
  id: Type.String(),                                 //   type: 'object',
  name: Type.String(),                               //   properties: { 
  timestamp: Type.Integer()                          //     id: { 
})                                                   //       type: 'string' 
                                                     //     },
                                                     //     name: { 
                                                     //       type: 'string' 
                                                     //     },
                                                     //     timestamp: { 
                                                     //       type: 'integer' 
                                                     //     }
                                                     //   }, 
                                                     //   required: [
                                                     //     'id',
                                                     //     'name',
                                                     //     'timestamp'
                                                     //   ]
                                                     // } 

//--------------------------------------------------------------------------------------------
//
// ... then infer back to the original static type this way.
//
//--------------------------------------------------------------------------------------------

type T = Static<typeof T>                            // type T = {
                                                     //   id: string,
                                                     //   name: string,
                                                     //   timestamp: number
                                                     // }

//--------------------------------------------------------------------------------------------
//
// ... then use the type both as JSON schema and as a TypeScript type.
//
//--------------------------------------------------------------------------------------------

import { Value } from '@sinclair/typebox/value'

function receive(value: T) {                         // ... as a Static Type

  if(Value.Check(T, value)) {                        // ... as a JSON Schema
  
    // ok...
  }
}

Types

TypeBox types are JSON schema fragments that can be composed into more complex types. Each fragment is structured such that a JSON schema compliant validator can runtime assert a value the same way TypeScript will statically assert a type. TypeBox provides a set of Standard types which are used create JSON schema compliant schematics as well as an Extended type set used to create schematics for constructs native to JavaScript.

Standard Types

The following table lists the Standard TypeBox types. These types are fully compatible with the JSON Schema Draft 6 specification.

┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ TypeBoxTypeScriptJSON Schema                    │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Any()type T = anyconst T = { }                  │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Unknown()type T = unknownconst T = { }                  │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.String()type T = stringconst T = {                    │
│                                │                             │   type: 'string'               │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Number()type T = numberconst T = {                    │
│                                │                             │   type: 'number'               │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Integer()type T = numberconst T = {                    │
│                                │                             │   type: 'integer'              │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Boolean()type T = booleanconst T = {                    │
│                                │                             │   type: 'boolean'              │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Null()type T = nullconst T = {                    │
│                                │                             │   type: 'null'                 │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Literal(42)type T = 42const T = {                    │
│                                │                             │   const: 42,                   │
│                                │                             │   type: 'number'               │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Array(type T = number[]const T = {                    │
│   Type.Number()                │                             │   type: 'array',               │
│ )                              │                             │   items: {                     │
│                                │                             │     type: 'number'             │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({type T = {const T = {                    │
│   x: Type.Number(),            │   x: number,                │   type: 'object',              │
│   y: Type.Number()             │   y: number                 │   required: ['x', 'y'],        │
│ })}                           │   properties: {                │
│                                │                             │     x: {                       │
│                                │                             │       type: 'number'           │
│                                │                             │     }, {                       │
│                                │                             │       type: 'number'           │
│                                │                             │     }                          │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Tuple([type T = [number, number]const T = {                    │
│   Type.Number(),               │                             │   type: 'array',               │
│   Type.Number()                │                             │   items: [{                    │
│ ])                             │                             │      type: 'number'            │
│                                │                             │    }, {                        │
│                                │                             │      type: 'number'            │
│                                │                             │    }],                         │
│                                │                             │    additionalItems: false,     │
│                                │                             │    minItems: 2,                │
│                                │                             │    maxItems: 2                 │
│                                │                             │ }                              │
│                                │                             │                                │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ enum Foo {enum Foo {const T = {                    │
│   A,A,                        │   anyOf: [{                    │
│   BB                         │     type: 'number',            │
│ }}const: 0                   │
│                                │                             │   }, {                         │
│ const T = Type.Enum(Foo)type T = Foo                │     type: 'number',            │
│                                │                             │     const: 1                   │
│                                │                             │   }]                           │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.KeyOf(type T = keyof {const T = {                    │
│   Type.Object({                │   x: number,                │   anyOf: [{                    │
│     x: Type.Number(),          │   y: number                 │     type: 'string',            │
│     y: Type.Number()}const: 'x'                 │
│   })                           │                             │   }, {                         │
│ )                              │                             │     type: 'string',            │
│                                │                             │     const: 'y'                 │
│                                │                             │   }]                           │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Union([type T = string | numberconst T = {                    │
│   Type.String(),               │                             │   anyOf: [{                    │
│   Type.Number()                │                             │      type: 'string'            │
│ ])                             │                             │   }, {                         │
│                                │                             │      type: 'number'            │
│                                │                             │   }]                           │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Intersect([type T = {const T = {                    │
│   Type.Object({                │   x: number                 │   allOf: [{                    │
│     x: Type.Number()} & {                       │     type: 'object',            │
│   }),                          │   y: number                 │     required: ['x'],           │
│   Type.Object({}                           │     properties: {              │
│     y: Type.Number()           │                             │       x: {                     │
│   ])                           │                             │         type: 'number'         │
│ ])                             │                             │       }                        │
│                                │                             │     }                          │
│                                │                             │   }, {                         │
│                                │                             │     type: 'object',            |
│                                │                             │     required: ['y'],           │
│                                │                             │     properties: {              │
│                                │                             │       y: {                     │
│                                │                             │         type: 'number'         │
│                                │                             │       }                        │
│                                │                             │   }]                           │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Composite([type T = {const T = {                    │
│   Type.Object({                │   x: number                 │   type: 'object',              │
│     x: Type.Number()           │   y: number                 │   required: ['x', 'y'],        │
│   }),}                           │   properties: {                │
│   Type.Object({                │                             │     x: {                       │
│     y: Type.Number()           │                             │       type: 'number'           │
│   })                           │                             │     },                         │
│ ])                             │                             │     y: {                       │
│                                │                             │       type: 'number'           │
│                                │                             │     }                          │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Never()type T = neverconst T = {                    │
│                                │                             │   not: {}                      │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Not(            | type T = stringconst T = {|   Type.Union([                 │                             │   allOf: [{                    │
│     Type.Literal('x'),         │                             │     not: {                     │
│     Type.Literal('y'),         │                             │       anyOf: [                 │
│     Type.Literal('z')          │                             │         { const: 'x' },        │
│   ]),                          │                             │         { const: 'y' },        │
│   Type.String()                │                             │         { const: 'z' }         │
│ )                              │                             │       ]                        │
│                                │                             │     }                          │
│                                │                             │   }, {                         │
│                                │                             │     type: 'string'             │
│                                │                             │   }]                           │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Extends(type T =const T = {                    │
│   Type.String(),string extends numberconst: false,                │
│   Type.Number(),true : false               │   type: 'boolean'              │
│   Type.Literal(true),          │                             │ }                              │
│   Type.Literal(false)          │                             │                                │
│ )                              │                             │                                │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Extract(type T = Extract<const T = {                    │
│   Type.Union([string | number,          │   type: 'string'               │
│     Type.String(),string}                              │
│     Type.Number(),>                           │                                │
│   ]),                          │                             │                                │
│   Type.String()                │                             │                                │
│ )                              │                             │                                │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Exclude(type T = Exclude<const T = {                    │
│   Type.Union([string | number,          │   type: 'number'               │
│     Type.String(),string}                              │
│     Type.Number(),>                           │                                │
│   ]),                          │                             │                                │
│   Type.String()                │                             │                                │
│ )                              │                             │                                │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Record(type T = Record<const T = {                    │
│   Type.String(),string,                   │   type: 'object',              │
│   Type.Number()number,                   │   patternProperties: {         │
│ )>'^.*$': {                  │
│                                │                             │       type: 'number'           │
│                                │                             │     }                          │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Partial(type T = Partial<{const T = {                    │
│   Type.Object({                │   x: number,                │   type: 'object',              │
│     x: Type.Number(),          │   y: number                 │   properties: {                │
│     y: Type.Number()           | }>                          │     x: {                       │
│   })                           │                             │       type: 'number'           │
│ )                              │                             │     },                         │
│                                │                             │     y: {                       │
│                                │                             │       type: 'number'           │
│                                │                             │     }                          │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Required(type T = Required<{const T = {                    │
│   Type.Object({                │   x?: number,               │   type: 'object',              │
│     x: Type.Optional(          │   y?: number                │   required: ['x', 'y'],        │
│       Type.Number()            | }>                          │   properties: {                │
│     ),                         │                             │     x: {                       │
│     y: Type.Optional(          │                             │       type: 'number'           │
│       Type.Number()            │                             │     },                         │
│     )                          │                             │     y: {                       │
│   })                           │                             │       type: 'number'           │
│ )                              │                             │     }                          │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Pick(type T = Pick<{const T = {                    │
│   Type.Object({                │   x: number,                │   type: 'object',              │
│     x: Type.Number(),          │   y: number                 │   properties: {                │
│     y: Type.Number()           | }, 'x'>                     │     x: {                       │
│   }), ['x']                    │                             │       type: 'number'           │
│ )                              │                             │     }                          │
│                                │                             │   },                           │
│                                │                             │   required: ['x']              │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Omit(type T = Omit<{const T = {                    │
│   Type.Object({                │   x: number,                │   type: 'object',              │
│     x: Type.Number(),          │   y: number                 │   properties: {                │
│     y: Type.Number()           | }, 'x'>                     │     y: {                       │
│   }), ['x']                    │                             │       type: 'number'           │
│ )                              │                             │     }                          │
│                                │                             │   },                           │
│                                │                             │   required: ['y']              │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const A = Type.Object({type A = {const T = {                    │
│    x: Type.Number(),           │   x: number,                │   $ref: 'A'                    │
│    y: Type.Number()            │   y: number}                              │
│ }, { $id: 'T' })               | }                           │                                │
│                                │                             │                                │
│ const T = Type.Ref(A)type T = A                  │                                │
│                                │                             │                                │
│                                │                             │                                │
│                                │                             │                                │
│                                │                             │                                │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘

Extended Types

TypeBox provides several extended types that can be used to produce schematics for common JavaScript constructs. These types can not be used with standard JSON schema validators; but are useful to help frame schematics for RPC interfaces that may receive JSON validated data. Extended types are prefixed with the [Extended] doc comment for convenience. The following table lists the supported types.

┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ TypeBoxTypeScriptExtended Schema                │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Constructor([type T = new (const T = {                    │
│   Type.String(),               │  arg0: string,              │   type: 'object',              │
│   Type.Number()                │  arg1: number               │   instanceOf: 'Constructor',   │
│ ], Type.Boolean())) => boolean                │   parameters: [{               │
│                                │                             │     type: 'string'             │
│                                │                             │   }, {                         │
│                                │                             │     type: 'number'             │
│                                │                             │   }],                          │
│                                │                             │   return: {                    │
│                                │                             │     type: 'boolean'            │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Function([type T = (const T = {|   Type.String(),               │  arg0: string,              │   type : 'object',             │
│   Type.Number()                │  arg1: number               │   instanceOf: 'Function',      │
│ ], Type.Boolean())) => boolean                │   parameters: [{               │
│                                │                             │     type: 'string'             │
│                                │                             │   }, {                         │
│                                │                             │     type: 'number'             │
│                                │                             │   }],                          │
│                                │                             │   return: {                    │
│                                │                             │     type: 'boolean'            │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Promise(type T = Promise<string>const T = {                    │
│   Type.String()                │                             │   type: 'object',              │
│ )                              │                             │   instanceOf: 'Promise',       │
│                                │                             │   item: {                      │
│                                │                             │     type: 'string'             │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Uint8Array()type T = Uint8Arrayconst T = {                    │
│                                │                             │   type: 'object',              │
│                                │                             │   instanceOf: 'Uint8Array'     │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Date()type T = Dateconst T = {                    │
│                                │                             │   type: 'object',              │
│                                │                             │   instanceOf: 'Date'           │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Undefined()type T = undefinedconst T = {                    │
│                                │                             │   type: 'null',                │
│                                │                             │   typeOf: 'Undefined'          │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.RegEx(/foo/)type T = stringconst T = {                    │
│                                │                             │    type: 'string',             │
│                                │                             │    pattern: 'foo'              │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Symbol()type T = symbolconst T = {                    │
│                                │                             │   type: 'null',                │
│                                │                             │   typeOf: 'Symbol'             │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.BigInt()type T = bigint             │ const T = {                    │
│                                │                             │   type: 'null',                │
│                                │                             │   typeOf: 'BigInt'             │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Void()type T = voidconst T = {                    │
│                                │                             │   type: 'null'                 │
│                                │                             │   typeOf: 'Void'               │
│                                │                             │ }                              │
│                                │                             │                                │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘

Modifiers

TypeBox provides modifiers that allow schema properties to be statically inferred as readonly or optional. The following table shows the supported modifiers and how they map between TypeScript and JSON Schema.

┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ TypeBoxTypeScriptJSON Schema                    │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({type T = {const T = {                    │
│   name: Type.Optional(         │   name?: string             │   type: 'object',              │
│     Type.String()}                           │   properties: {                │
│   )                            │                             │     name: {                    │
│ })  	                         │                             │       type: 'string'           │
│                                │                             │     }                          │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({type T = {const T = {                    │
│   name: Type.Readonly(readonly name: string     │   type: 'object',              │
│     Type.String()}                           │   properties: {                │
│   )                            │                             │     name: {                    │
│ })  	                         │                             │       type: 'string'           │
│                                │                             │     }                          │
│                                │                             │   },                           │
│                                │                             │   required: ['name']           │
│                                │                             │ }                              │
│                                │                             │                                │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({type T = {const T = {                    │
│   name: Type.ReadonlyOptional(readonly name?: string    │   type: 'object',              │
│     Type.String()}                           │   properties: {                │
│   )                            │                             │     name: {                    │
│ })  	                         │                             │       type: 'string'           │
│                                │                             │     }                          │
│                                │                             │   }                            │
│                                │                             │ }                              │
│                                │                             │                                │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘

Options

You can pass JSON Schema options on the last argument of any type. Option hints specific to each type are provided for convenience.

// String must be an email
const T = Type.String({                              // const T = { 
  format: 'email'                                    //   type: 'string',
})                                                   //   format: 'email' 
                                                     // }

// Mumber must be a multiple of 2
const T = Type.Number({                              // const T = { 
  multipleOf: 2                                      //  type: 'number', 
})                                                   //  multipleOf: 2 
                                                     // }

// Array must have at least 5 integer values
const T = Type.Array(Type.Integer(), {               // const T = { 
  minItems: 5                                        //   type: 'array',
})                                                   //   minItems: 5,        
                                                     //   items: { 
                                                     //     type: 'integer'
                                                     //   }
                                                     // }

Generic Types

Generic types can be created with generic functions constrained to type TSchema. The following creates a generic Vector<T> type.

import { Type, Static, TSchema } from '@sinclair/typebox'

const Vector = <T extends TSchema>(t: T) => Type.Object({ x: t, y: t, z: t })

const NumberVector = Vector(Type.Number())           // const NumberVector = {
                                                     //   type: 'object',
                                                     //   required: ['x', 'y', 'z'],
                                                     //   properties: {
                                                     //     x: { type: 'number' },
                                                     //     y: { type: 'number' },
                                                     //     z: { type: 'number' }
                                                     //   }
                                                     // }

type NumberVector = Static<typeof NumberVector>      // type NumberVector = {
                                                     //   x: number,
                                                     //   y: number,
                                                     //   z: number
                                                     // }

const BooleanVector = Vector(Type.Boolean())         // const BooleanVector = {
                                                     //   type: 'object',
                                                     //   required: ['x', 'y', 'z'],
                                                     //   properties: {
                                                     //     x: { type: 'boolean' },
                                                     //     y: { type: 'boolean' },
                                                     //     z: { type: 'boolean' }
                                                     //   }
                                                     // }

type BooleanVector = Static<typeof BooleanVector>    // type BooleanVector = {
                                                     //   x: boolean,
                                                     //   y: boolean,
                                                     //   z: boolean
                                                     // }

The following creates a generic Nullable<T> type.

const Nullable = <T extends TSchema>(schema: T) => Type.Union([schema, Type.Null()])

const T = Nullable(Type.String())                   // const T = {
                                                    //   anyOf: [
                                                    //     { type: 'string' },
                                                    //     { type: 'null' }
                                                    //   ]
                                                    // }

type T = Static<typeof T>                           // type T = string | null

Reference Types

Reference types are supported with Type.Ref(...). The target type must specify a valid $id.

const T = Type.String({ $id: 'T' })                  // const T = {
                                                     //    $id: 'T',
                                                     //    type: 'string'
                                                     // }
                                             
const R = Type.Ref(T)                                // const R = {
                                                     //    $ref: 'T'
                                                     // }

Recursive Types

Recursive types are supported with Type.Recursive(...).

const Node = Type.Recursive(Node => Type.Object({    // const Node = {
  id: Type.String(),                                 //   $id: 'Node',
  nodes: Type.Array(Node)                            //   type: 'object',
}), { $id: 'Node' })                                 //   properties: {
                                                     //     id: {
                                                     //       type: 'string'
                                                     //     },
                                                     //     nodes: {
                                                     //       type: 'array',
                                                     //       items: {
                                                     //         $ref: 'Node'
                                                     //       }
                                                     //     }
                                                     //   },
                                                     //   required: [
                                                     //     'id',
                                                     //     'nodes'
                                                     //   ]
                                                     // }

type Node = Static<typeof Node>                      // type Node = {
                                                     //   id: string
                                                     //   nodes: Node[]
                                                     // }

function test(node: Node) {
  const id = node.nodes[0].nodes[0].id               // id is string
}

Conditional Types

Conditional types are supported with Extends, Exclude and Extract.

TypeScript

type T0 = string extends number ? true : false                                                 
//   ^ false
type T1 = Extract<string | number, number>                                                     
//   ^ number
type T2 = Exclude<string | number, number>                                                     
//   ^ string

TypeBox

const T0 = Type.Extends(Type.String(), Type.Number(), Type.Literal(true), Type.Literal(false)) 
//    ^ TLiteral<false>
const T1 = Type.Extract(Type.Union([Type.String(), Type.Number()]), Type.Number())             
//    ^ TNumber
const T2 = Type.Exclude(Type.Union([Type.String(), Type.Number()]), Type.Number())             
//    ^ TString<string>

Unsafe

Use Type.Unsafe(...) to create custom schematics with user defined inference rules.

const T = Type.Unsafe<string>({ type: 'number' })    // const T = {
                                                     //   type: 'number'
                                                     // }

type T = Static<typeof T>                            // type T = string

The Type.Unsafe(...) type can be useful to express specific OpenAPI schema representations.

import { Type, Static, TSchema } from '@sinclair/typebox'

// Nullable<T>

function Nullable<T extends TSchema>(schema: T) {
  return Type.Unsafe<Static<T> | null>({ ...schema, nullable: true })
}

const T = Nullable(Type.String())                    // const T = {
                                                     //   type: 'string',
                                                     //   nullable: true
                                                     // }

type T = Static<typeof T>                            // type T = string | null

// StringEnum<string[]>

function StringEnum<T extends string[]>(values: [...T]) {
  return Type.Unsafe<T[number]>({ type: 'string', enum: values })
}

const T = StringEnum(['A', 'B', 'C'])                // const T = {
                                                     //   enum: ['A', 'B', 'C']
                                                     // }

type T = Static<typeof T>                            // type T = 'A' | 'B' | 'C'

Guards

TypeBox provides a TypeGuard module that can be used for reflection and asserting values as types.

import { Type, TypeGuard } from '@sinclair/typebox'

const T = Type.String()

if(TypeGuard.TString(T)) {
    
  // T is TString
}

Strict

TypeBox schemas contain the Kind and Modifier symbol properties. These properties are used for type composition and reflection. These properties are not strictly valid JSON schema; so in some cases it may be desirable to omit them. TypeBox provides a Type.Strict() function that will omit these properties if necessary.

const T = Type.Object({                              // const T = {
  name: Type.Optional(Type.String())                 //   [Kind]: 'Object',
})                                                   //   type: 'object',
                                                     //   properties: {
                                                     //     name: {
                                                     //       [Kind]: 'String',
                                                     //       type: 'string',
                                                     //       [Modifier]: 'Optional'
                                                     //     }
                                                     //   }
                                                     // }

const U = Type.Strict(T)                             // const U = {
                                                     //   type: 'object', 
                                                     //   properties: { 
                                                     //     name: { 
                                                     //       type: 'string' 
                                                     //     } 
                                                     //   } 
                                                     // }

Values

TypeBox provides an optional utility module that can be used to perform common operations on JavaScript values. This module includes functionality to create, check and cast values from types as well as check equality, clone, diff and patch JavaScript values. This module is provided via optional import.

import { Value } from '@sinclair/typebox/value'

Create

Use the Create function to create a value from a type. TypeBox will use default values if specified.

const T = Type.Object({ x: Type.Number(), y: Type.Number({ default: 42 }) })

const A = Value.Create(T)                            // const A = { x: 0, y: 42 }

Clone

Use the Clone function to deeply clone a value

const A = Value.Clone({ x: 1, y: 2, z: 3 })          // const A = { x: 1, y: 2, z: 3 }

Check

Use the Check function to type check a value

const T = Type.Object({ x: Type.Number() })

const R = Value.Check(T, { x: 1 })                   // const R = true

Convert

Use the Convert function to convert a value into its target type if a reasonable conversion is possible.

const T = Type.Object({ x: Type.Number(), y: Type.Number() })

const R1 = Value.Convert(T, { x: '3.14' })          // const R1 = { x: 3.14 }

const R2 = Value.Convert(T, { x: 'not a number' })  // const R2 = { x: 'not a number' }

Cast

Use the Cast function to cast a value into a type. The cast function will retain as much information as possible from the original value.

const T = Type.Object({ x: Type.Number(), y: Type.Number() }, { additionalProperties: false })

const X = Value.Cast(T, null)                        // const X = { x: 0, y: 0 }

const Y = Value.Cast(T, { x: 1 })                    // const Y = { x: 1, y: 0 }

const Z = Value.Cast(T, { x: 1, y: 2, z: 3 })        // const Z = { x: 1, y: 2 }

Equal

Use the Equal function to deeply check for value equality.

const R = Value.Equal(                               // const R = true
  { x: 1, y: 2, z: 3 },
  { x: 1, y: 2, z: 3 }
)

Hash

Use the Hash function to create a FNV1A-64 non cryptographic hash of a value.

const A = Value.Hash({ x: 1, y: 2, z: 3 })          // const A = 2910466848807138541n

const B = Value.Hash({ x: 1, y: 4, z: 3 })          // const B = 1418369778807423581n

Diff

Use the Diff function to produce a sequence of edits to transform one value into another.

const E = Value.Diff(                               // const E = [
  { x: 1, y: 2, z: 3 },                             //   { type: 'update', path: '/y', value: 4 },
  { y: 4, z: 5, w: 6 }                              //   { type: 'update', path: '/z', value: 5 },
)                                                   //   { type: 'insert', path: '/w', value: 6 },
                                                    //   { type: 'delete', path: '/x' }
                                                    // ]

Patch

Use the Patch function to apply edits

const A = { x: 1, y: 2 }

const B = { x: 3 }

const E = Value.Diff(A, B)                           // const E = [
                                                     //   { type: 'update', path: '/x', value: 3 },
                                                     //   { type: 'delete', path: '/y' }
                                                     // ]

const C = Value.Patch<typeof B>(A, E)                // const C = { x: 3 }

Errors

Use the Errors function enumerate validation errors.

const T = Type.Object({ x: Type.Number(), y: Type.Number() })

const R = [...Value.Errors(T, { x: '42' })]          // const R = [{
                                                     //   schema: { type: 'number' },
                                                     //   path: '/x',
                                                     //   value: '42',
                                                     //   message: 'Expected number'
                                                     // }, {
                                                     //   schema: { type: 'number' },
                                                     //   path: '/y',
                                                     //   value: undefined,
                                                     //   message: 'Expected number'
                                                     // }]

Pointer

Use ValuePointer to perform mutable updates on existing values using RFC6901 JSON Pointers.

import { ValuePointer } from '@sinclair/typebox/value'

const A = { x: 0, y: 0, z: 0 }

ValuePointer.Set(A, '/x', 1)                         // const A = { x: 1, y: 0, z: 0 }
ValuePointer.Set(A, '/y', 1)                         // const A = { x: 1, y: 1, z: 0 }
ValuePointer.Set(A, '/z', 1)                         // const A = { x: 1, y: 1, z: 1 }

TypeCheck

TypeBox types target JSON Schema draft 6 so are compatible with any validator that supports this specification. TypeBox also provides a built in type checking compiler designed specifically for high performance compilation and value assertion.

The following sections detail using Ajv and TypeBox’s compiler infrastructure.

Ajv

The following shows the recommended setup for Ajv.

$ npm install ajv ajv-formats --save
import { Type }   from '@sinclair/typebox'
import addFormats from 'ajv-formats'
import Ajv        from 'ajv'

const ajv = addFormats(new Ajv({}), [
  'date-time', 
  'time', 
  'date', 
  'email',  
  'hostname', 
  'ipv4', 
  'ipv6', 
  'uri', 
  'uri-reference', 
  'uuid',
  'uri-template', 
  'json-pointer', 
  'relative-json-pointer', 
  'regex'
])

const C = ajv.compile(Type.Object({                
  x: Type.Number(),
  y: Type.Number(),
  z: Type.Number()
}))

const R = C({ x: 1, y: 2, z: 3 })                    // const R = true 

TypeCompiler

The TypeBox TypeCompiler is a high performance JIT compiler that transforms TypeBox types into optimized JavaScript validation routines. The compiler is tuned for fast compilation as well as fast value assertion. It is designed to serve as a validation backend that can be integrated into larger applications; but can also be used as a general purpose validator.

The TypeCompiler is provided as an optional import.

import { TypeCompiler } from '@sinclair/typebox/compiler'

Use the Compile(...) function to compile a type.

const C = TypeCompiler.Compile(Type.Object({         // const C: TypeCheck<TObject<{
  x: Type.Number(),                                  //     x: TNumber;
  y: Type.Number(),                                  //     y: TNumber;
  z: Type.Number()                                   //     z: TNumber;
}))                                                  // }>>

const R = C.Check({ x: 1, y: 2, z: 3 })              // const R = true

Use the Errors(...) function to produce diagnostic errors for a value. The Errors(...) function will return an iterator that if enumerated; will perform an exhaustive check across the entire value and yield any error found. For performance, this function should only be called after failed Check(...). Applications may also choose to yield only the first value to avoid exhaustive error generation.

const C = TypeCompiler.Compile(Type.Object({         // const C: TypeCheck<TObject<{
  x: Type.Number(),                                  //     x: TNumber;
  y: Type.Number(),                                  //     y: TNumber;
  z: Type.Number()                                   //     z: TNumber;
}))                                                  // }>>

const value = { }

const errors = [...C.Errors(value)]                  // const errors = [{
                                                     //   schema: { type: 'number' },
                                                     //   path: '/x',
                                                     //   value: undefined,
                                                     //   message: 'Expected number'
                                                     // }, {
                                                     //   schema: { type: 'number' },
                                                     //   path: '/y',
                                                     //   value: undefined,
                                                     //   message: 'Expected number'
                                                     // }, {
                                                     //   schema: { type: 'number' },
                                                     //   path: '/z',
                                                     //   value: undefined,
                                                     //   message: 'Expected number'
                                                     // }]

Compiled routines can be inspected with the .Code() function.

const C = TypeCompiler.Compile(Type.String())        // const C: TypeCheck<TString>

console.log(C.Code())                                // return function check(value) {
                                                     //   return (
                                                     //     (typeof value === 'string')
                                                     //   )
                                                     // }

TypeSystem

The TypeBox TypeSystem module provides functionality to define types above and beyond the Standard and Extended type sets as well as control various assertion polices. Configurations made to the TypeSystem module are observed by both TypeCompiler and Value modules.

The TypeSystem module is provided as an optional import.

import { TypeSystem } from '@sinclair/typebox/system'

Types

Use the Type(...) function to create a custom type. This function will return a type factory function that can be used to construct the type. The following creates a Point type.

type PointOptions = { }                              // The Type Options

type PointType = { x: number, y: number }            // The Static<T> Type

const Point = TypeSystem.Type<PointType, PointOptions>('Point', (options, value) => {
  return (
    typeof value === 'object' && value !== null &&
    typeof value.x === 'number' && 
    typeof value.y === 'number'
  )
})

const T = Point()

type T = Static<typeof T>                             // type T = { x: number, y: number }

const R = Value.Check(T, { x: 1, y: 2 })              // const R = true

Formats

Use the Format(...) function to create a custom string format. The following creates a custom string format that checks for lowercase strings.

TypeSystem.Format('lowercase', value => value === value.toLowerCase()) // format should be lowercase

const T = Type.String({ format: 'lowercase' })       

const A = Value.Check(T, 'action')                   // const A = true

const B = Value.Check(T, 'ACTION')                   // const B = false

Policies

TypeBox validates using JSON Schema assertion policies by default. It is possible to override these policies and have TypeBox assert using TypeScript policies. The following overrides are available.

// Allow arrays to validate as object types (default is false)
//
// const A: {} = [] - allowed in TS

TypeSystem.AllowArrayObjects = true                  

// Allow numeric values to be NaN or + or - Infinity (default is false)
//
// const A: number = NaN - allowed in TS

TypeSystem.AllowNaN = true                      

Benchmark

This project maintains a set of benchmarks that measure Ajv, Value and TypeCompiler compilation and validation performance. These benchmarks can be run locally by cloning this repository and running npm run benchmark. The results below show for Ajv version 8.11.2.

For additional comparative benchmarks, please refer to typescript-runtime-type-benchmarks.

Compile

This benchmark measures compilation performance for varying types. You can review this benchmark here.

┌────────────────────────────┬────────────┬──────────────┬──────────────┬──────────────┐
          (index)IterationsAjvTypeCompilerPerformance  │
├────────────────────────────┼────────────┼──────────────┼──────────────┼──────────────┤
│ Literal_String1000'    260 ms''      8 ms''   32.50 x' │
│ Literal_Number1000'    198 ms''      4 ms''   49.50 x' │
│ Literal_Boolean1000'    185 ms''      5 ms''   37.00 x' │
│ Primitive_Number1000'    176 ms''      9 ms''   19.56 x' │
│ Primitive_String1000'    161 ms''      9 ms''   17.89 x' │
│ Primitive_String_Pattern1000'    215 ms''     12 ms''   17.92 x' │
│ Primitive_Boolean1000'    133 ms''      5 ms''   26.60 x' │
│ Primitive_Null1000'    143 ms''      8 ms''   17.88 x' │
│ Object_Unconstrained1000'   1181 ms''     38 ms''   31.08 x' │
│ Object_Constrained1000'   1168 ms''     32 ms''   36.50 x' │
│ Tuple_Primitive1000'    557 ms''     16 ms''   34.81 x' │
│ Tuple_Object1000'   1119 ms''     17 ms''   65.82 x' │
│ Composite_Intersect1000'    569 ms''     22 ms''   25.86 x' │
│ Composite_Union1000'    513 ms''     23 ms''   22.30 x' │
│ Math_Vector41000'    802 ms''     10 ms''   80.20 x' │
│ Math_Matrix41000'    395 ms''     12 ms''   32.92 x' │
│ Array_Primitive_Number1000'    282 ms''      8 ms''   35.25 x' │
│ Array_Primitive_String1000'    321 ms''      5 ms''   64.20 x' │
│ Array_Primitive_Boolean1000'    364 ms''      5 ms''   72.80 x' │
│ Array_Object_Unconstrained1000'   1573 ms''     18 ms''   87.39 x' │
│ Array_Object_Constrained1000'   1270 ms''     20 ms''   63.50 x' │
│ Array_Tuple_Primitive1000'    973 ms''     18 ms''   54.06 x' │
│ Array_Tuple_Object1000'   1253 ms''     16 ms''   78.31 x' │
│ Array_Composite_Intersect1000'    927 ms''     20 ms''   46.35 x' │
│ Array_Composite_Union1000'   1123 ms''     16 ms''   70.19 x' │
│ Array_Math_Vector41000'   1068 ms''     10 ms''  106.80 x' │
│ Array_Math_Matrix41000'    488 ms''      7 ms''   69.71 x' │
└────────────────────────────┴────────────┴──────────────┴──────────────┴──────────────┘

Validate

This benchmark measures validation performance for varying types. You can review this benchmark here.

┌────────────────────────────┬────────────┬──────────────┬──────────────┬──────────────┬──────────────┐
          (index)IterationsValueCheckAjvTypeCompilerPerformance  │
├────────────────────────────┼────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
│ Literal_String1000000'     26 ms''      6 ms''      6 ms''    1.00 x' │
│ Literal_Number1000000'     21 ms''     19 ms''     11 ms''    1.73 x' │
│ Literal_Boolean1000000'     19 ms''     18 ms''     10 ms''    1.80 x' │
│ Primitive_Number1000000'     24 ms''     19 ms''     11 ms''    1.73 x' │
│ Primitive_String1000000'     26 ms''     17 ms''     10 ms''    1.70 x' │
│ Primitive_String_Pattern1000000'    159 ms''     45 ms''     37 ms''    1.22 x' │
│ Primitive_Boolean1000000'     23 ms''     17 ms''     10 ms''    1.70 x' │
│ Primitive_Null1000000'     23 ms''     18 ms''     10 ms''    1.80 x' │
│ Object_Unconstrained1000000'    809 ms''     35 ms''     30 ms''    1.17 x' │
│ Object_Constrained1000000'   1060 ms''     56 ms''     45 ms''    1.24 x' │
│ Object_Recursive1000000'   4965 ms''    397 ms''    100 ms''    3.97 x' │
│ Tuple_Primitive1000000'    159 ms''     22 ms''     16 ms''    1.38 x' │
│ Tuple_Object1000000'    658 ms''     31 ms''     27 ms''    1.15 x' │
│ Composite_Intersect1000000'    695 ms''     26 ms''     22 ms''    1.18 x' │
│ Composite_Union1000000'    503 ms''     24 ms''     19 ms''    1.26 x' │
│ Math_Vector41000000'    259 ms''     22 ms''     14 ms''    1.57 x' │
│ Math_Matrix41000000'   1007 ms''     40 ms''     29 ms''    1.38 x' │
│ Array_Primitive_Number1000000'    262 ms''     23 ms''     17 ms''    1.35 x' │
│ Array_Primitive_String1000000'    241 ms''     27 ms''     24 ms''    1.13 x' │
│ Array_Primitive_Boolean1000000'    141 ms''     23 ms''     20 ms''    1.15 x' │
│ Array_Object_Unconstrained1000000'   4976 ms''     70 ms''     67 ms''    1.04 x' │
│ Array_Object_Constrained1000000'   5234 ms''    143 ms''    120 ms''    1.19 x' │
│ Array_Object_Recursive1000000'  19605 ms''   1909 ms''    350 ms''    5.45 x' │
│ Array_Tuple_Primitive1000000'    706 ms''     39 ms''     32 ms''    1.22 x' │
│ Array_Tuple_Object1000000'   2951 ms''     67 ms''     63 ms''    1.06 x' │
│ Array_Composite_Intersect1000000'   2969 ms''     49 ms''     44 ms''    1.11 x' │
│ Array_Composite_Union1000000'   2191 ms''     77 ms''     41 ms''    1.88 x' │
│ Array_Math_Vector41000000'   1164 ms''     41 ms''     25 ms''    1.64 x' │
│ Array_Math_Matrix41000000'   4903 ms''    115 ms''     99 ms''    1.16 x' │
└────────────────────────────┴────────────┴──────────────┴──────────────┴──────────────┴──────────────┘

Compression

The following table lists esbuild compiled and minified sizes for each TypeBox module.

┌──────────────────────┬────────────┬────────────┬─────────────┐
       (index)CompiledMinifiedCompression │
├──────────────────────┼────────────┼────────────┼─────────────┤
│ typebox/compiler     │ '108.8 kb'' 48.9 kb''2.23 x'   │
│ typebox/errors       │ ' 93.2 kb'' 41.5 kb''2.24 x'   │
│ typebox/system       │ ' 60.0 kb'' 24.6 kb''2.43 x'   │
│ typebox/value        │ '153.5 kb'' 66.7 kb''2.30 x'   │
│ typebox              │ ' 58.7 kb'' 24.1 kb''2.43 x'   │
└──────────────────────┴────────────┴────────────┴─────────────┘

Contribute

TypeBox is open to community contribution. Please ensure you submit an open issue before submitting your pull request. The TypeBox project preferences open community discussion prior to accepting new features.