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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 constructs 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 checking 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 and 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 small JSON schema fragments which can compose into more complex types though function composition. Each fragment is strictly defined to match to the static type checking rules of TypeScript. TypeBox provides a Standard type set which produces standards compliant JSON schema as well as an Extended type set used to define native JavaScript constructs.

Standard Types

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

┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
 TypeBox                         TypeScript                   JSON Schema                    
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Any()            type T = any                 const T = { }                  
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Unknown()        type T = unknown             const T = { }                  
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.String()         type T = string              const T = {                    
                                                                type: 'string'               
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Number()         type T = number              const T = {                    
                                                                type: 'number'               
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Integer()        type T = number              const T = {                    
                                                                type: 'integer'              
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Boolean()        type T = boolean             const T = {                    
                                                                type: 'boolean'              
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Null()           type T = null                const T = {                    
                                                                 type: 'null'                
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Literal(42)      type T = 42                  const 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: [{                    
   B                               B                              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 | number     const 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 | string           type: 'object',              
     x: Type.Number()              y: number                    properties: {   }),}                                x: {                       
   Type.Object({                                                    anyOf: [                 
     x: Type.String()                                                 { type: 'number' },    
     y: Type.Number()                                                 { type: 'string' }     
   })                                                               ]                        
 ])                                                               },                         
                                                                  y: {                       
                                                                    type: 'number'           
                                                                  }                          
                                                                },                           
                                                                required: ['x', 'y']         
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Never()          type T = never               const T = {                    
                                                                allOf: [{                    
                                                                  type: 'boolean',           
                                                                  const: false               
                                                                }, {                         
                                                                  type: 'boolean',           
                                                                  const: true                
                                                                }]                           
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Not(            | type T = string              const 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 number         const: 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                                                  
                                                                                             
                                                                                             
                                                                                             
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const A = Type.Object({         type T = {const T = {                    
    x: Type.Number(),              x: number,                   $id: 'T'                     
    y: Type.Number()               y: number                    type: 'object', }, { $id: 'T' })               | }                              required: ['x', 'y'],        
                                                                properties: {                
 const T = Type.Deref(                                            x: { type: 'number' },     
   Type.Ref(A)                                                    y: { type: 'number' },     
 )                                                              }                            
                                                              }                              
                                                                                             
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘

Extended Types

TypeBox provides several extended types that can be used to produce schematics for common JavaScript constructs. These types cannot 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 lists the supported types

┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
 TypeBox                         TypeScript                   Extended 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 = Uint8Array          const T = {                    
                                                                type: 'object',              
                                                                instanceOf: 'Uint8Array'     
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Date()           type T = Date                const T = {                    
                                                                type: 'object',              
                                                                instanceOf: 'Date'           
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Undefined()      type T = undefined           const T = {                    
                                                                type: 'null',                
                                                                typeOf: 'Undefined'          
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.RegEx(/foo/)     type T = string              const T = {                    
                                                                 type: 'string',             
                                                                 pattern: 'foo'              
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Symbol()         type T = symbol              const T = {                    
                                                                type: 'null',                
                                                                typeOf: 'Symbol'             
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.BigInt()         type T = bigint              const T = {                    
                                                                type: 'null',                
                                                                typeOf: 'BigInt'             
                                                              }                              
                                                                                             
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
 const T = Type.Void()           type T = void                const T = {                    
                                                                type: 'null'                 
                                                                typeOf: 'Void'               
                                                              }                              
                                                                                             
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘

Modifiers

TypeBox provides property modifier types that allow properties to be mapped with TypeScript readonly and optional. The following table shows the modifier types and how they map between TypeScript and JSON Schema.

┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
 TypeBox                         TypeScript                   JSON 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 compliant options on the last argument of any type. Option property hints 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. 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' }
                                                     //   }
                                                     // }

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

Reference Types

Reference types are supported with Type.Ref(...). Use Type.Deref(...) to dereference a type.

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

const U = Type.Deref(R)                              // const U = {
                                                     //    $id: 'T',
                                                     //    type: 'string'
                                                     // }

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. These work the same as in TypeScript.

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 schemas 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 allows for the expression of 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 for reflection and type assertion.

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 runtime type 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 additional 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)       Iterations      Ajv       TypeCompiler  Performance  
├──────────────────┼────────────┼──────────────┼──────────────┼──────────────┤
           Number     2000     '    451 ms'  '     16 ms'  '   28.19 x' 
           String     2000     '    338 ms'  '     14 ms'  '   24.14 x' 
          Boolean     2000     '    297 ms'  '     13 ms'  '   22.85 x' 
             Null     2000     '    265 ms'  '      8 ms'  '   33.13 x' 
            RegEx     2000     '    492 ms'  '     18 ms'  '   27.33 x' 
          ObjectA     2000     '   2744 ms'  '     55 ms'  '   49.89 x' 
          ObjectB     2000     '   3005 ms'  '     44 ms'  '   68.30 x' 
            Tuple     2000     '   1283 ms'  '     26 ms'  '   49.35 x' 
            Union     2000     '   1263 ms'  '     27 ms'  '   46.78 x' 
          Vector4     2000     '   1622 ms'  '     23 ms'  '   70.52 x' 
          Matrix4     2000     '    888 ms'  '     12 ms'  '   74.00 x' 
   Literal_String     2000     '    344 ms'  '     14 ms'  '   24.57 x' 
   Literal_Number     2000     '    389 ms'  '      8 ms'  '   48.63 x' 
  Literal_Boolean     2000     '    374 ms'  '      9 ms'  '   41.56 x' 
     Array_Number     2000     '    710 ms'  '     12 ms'  '   59.17 x' 
     Array_String     2000     '    739 ms'  '      9 ms'  '   82.11 x' 
    Array_Boolean     2000     '    732 ms'  '      7 ms'  '  104.57 x' 
    Array_ObjectA     2000     '   3733 ms'  '     42 ms'  '   88.88 x' 
    Array_ObjectB     2000     '   3602 ms'  '     42 ms'  '   85.76 x' 
      Array_Tuple     2000     '   2204 ms'  '     20 ms'  '  110.20 x' 
      Array_Union     2000     '   1533 ms'  '     24 ms'  '   63.88 x' 
    Array_Vector4     2000     '   2263 ms'  '     21 ms'  '  107.76 x' 
    Array_Matrix4     2000     '   1576 ms'  '     14 ms'  '  112.57 x' 
└──────────────────┴────────────┴──────────────┴──────────────┴──────────────┘

Validate

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

┌──────────────────┬────────────┬──────────────┬──────────────┬──────────────┬──────────────┐
     (index)       Iterations   ValueCheck       Ajv       TypeCompiler  Performance  
├──────────────────┼────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
           Number   1000000    '     30 ms'  '      7 ms'  '      6 ms'  '    1.17 x' 
           String   1000000    '     23 ms'  '     21 ms'  '     11 ms'  '    1.91 x' 
          Boolean   1000000    '     22 ms'  '     21 ms'  '     10 ms'  '    2.10 x' 
             Null   1000000    '     27 ms'  '     20 ms'  '     10 ms'  '    2.00 x' 
            RegEx   1000000    '    163 ms'  '     47 ms'  '     38 ms'  '    1.24 x' 
          ObjectA   1000000    '    654 ms'  '     41 ms'  '     24 ms'  '    1.71 x' 
          ObjectB   1000000    '   1173 ms'  '     59 ms'  '     41 ms'  '    1.44 x' 
            Tuple   1000000    '    124 ms'  '     24 ms'  '     17 ms'  '    1.41 x' 
            Union   1000000    '    332 ms'  '     26 ms'  '     16 ms'  '    1.63 x' 
        Recursive   1000000    '   3129 ms'  '    412 ms'  '    102 ms'  '    4.04 x' 
          Vector4   1000000    '    147 ms'  '     26 ms'  '     13 ms'  '    2.00 x' 
          Matrix4   1000000    '    576 ms'  '     41 ms'  '     28 ms'  '    1.46 x' 
   Literal_String   1000000    '     51 ms'  '     21 ms'  '     10 ms'  '    2.10 x' 
   Literal_Number   1000000    '     47 ms'  '     21 ms'  '     11 ms'  '    1.91 x' 
  Literal_Boolean   1000000    '     47 ms'  '     21 ms'  '     10 ms'  '    2.10 x' 
     Array_Number   1000000    '    490 ms'  '     33 ms'  '     18 ms'  '    1.83 x' 
     Array_String   1000000    '    502 ms'  '     31 ms'  '     25 ms'  '    1.24 x' 
    Array_Boolean   1000000    '    465 ms'  '     33 ms'  '     27 ms'  '    1.22 x' 
    Array_ObjectA   1000000    '  15463 ms'  '   2470 ms'  '   2052 ms'  '    1.20 x' 
    Array_ObjectB   1000000    '  18047 ms'  '   2497 ms'  '   2348 ms'  '    1.06 x' 
      Array_Tuple   1000000    '   1958 ms'  '     99 ms'  '     77 ms'  '    1.29 x' 
      Array_Union   1000000    '   5348 ms'  '    254 ms'  '     89 ms'  '    2.85 x' 
  Array_Recursive   1000000    '  54643 ms'  '   8870 ms'  '   1158 ms'  '    7.66 x' 
    Array_Vector4   1000000    '   2724 ms'  '    105 ms'  '     48 ms'  '    2.19 x' 
    Array_Matrix4   1000000    '  13821 ms'  '    437 ms'  '    266 ms'  '    1.64 x' 
└──────────────────┴────────────┴──────────────┴──────────────┴──────────────┴──────────────┘

Compression

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

┌──────────────────────┬────────────┬────────────┬─────────────┐
       (index)          Compiled    Minified   Compression 
├──────────────────────┼────────────┼────────────┼─────────────┤
 typebox/compiler      ' 65.4 kb'  ' 32.2 kb'   '2.03 x'   
 typebox/conditional   ' 45.5 kb'  ' 18.6 kb'   '2.45 x'   
 typebox/custom        '  0.6 kb'  '  0.2 kb'   '2.61 x'   
 typebox/format        '  0.6 kb'  '  0.2 kb'   '2.66 x'   
 typebox/guard         ' 23.8 kb'  ' 11.4 kb'   '2.08 x'   
 typebox/hash          '  4.2 kb'  '  1.8 kb'   '2.30 x'   
 typebox/system        ' 14.0 kb'  '  7.1 kb'   '1.96 x'   
 typebox/value         ' 90.0 kb'  ' 41.8 kb'   '2.15 x'   
 typebox               ' 12.0 kb'  '  6.4 kb'   '1.89 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.