$ npm install @sinclair/typebox --saveimport { Static, Type } from 'npm:@sinclair/typebox'import { Static, Type } from 'https://esm.sh/@sinclair/typebox'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
// }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
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...
}
}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.
The following table lists the Standard TypeBox types. These types are fully compatible with the JSON Schema Draft 6 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' │
│ │ │ }, │
│ │ │ y: { │
│ │ │ 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 I = { │ const T = { │
│ Type.Object({ │ x: number │ type: 'object', │
│ x: Type.Number() │ } & { │ required: ['x', 'y'], │
│ }), │ y: number │ properties: { │
│ Type.Object({ │ } │ x: { │
│ y: Type.Number() │ │ type: 'number' │
│ }) │ type T = { │ }, │
│ ]) │ [K in keyof I]: I[K] │ y: { │
│ │ } │ type: 'number' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Never() │ type T = never │ const T = { │
│ │ │ not: {} │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ 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 U = Type.Union([ │ type U = 'open' | 'close' │ const T = { │
│ Type.Literal('open'), │ │ type: 'string', │
│ Type.Literal('close') │ type T = `on${U}` │ pattern: '^on(open|close)$' │
│ ]) │ │ } │
│ │ │ │
│ const T = Type │ │ │
│ .TemplateLiteral([ │ │ │
│ Type.Literal('on'), │ │ │
│ U │ │ │
│ ]) │ │ │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ 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 │ required: ['x'], │
│ y: Type.Number() │ }, 'x'> │ properties: { │
│ }), ['x'] | │ x: { │
│ ) │ │ type: 'number' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Omit( │ type T = Omit<{ │ const T = { │
│ Type.Object({ │ x: number, │ type: 'object', │
│ x: Type.Number(), │ y: number │ required: ['y'], │
│ y: Type.Number() │ }, 'x'> │ properties: { │
│ }), ['x'] | │ y: { │
│ ) │ │ type: 'number' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Index( │ type T = { │ const T = { │
│ Type.Object({ │ x: number, │ type: 'number' │
│ x: Type.Number(), │ y: string │ } │
│ y: Type.String() │ }['x'] │ │
│ }), ['x'] │ │ │
│ ) │ │ │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const A = Type.Tuple([ │ type A = [0, 1] │ const T = { │
│ Type.Literal(0), │ type B = [2, 3] │ type: 'array', │
│ Type.Literal(1) │ type T = [...A, ...B] │ items: [ │
│ ]) │ │ { const: 0 }, │
│ const B = Type.Tuple([ │ │ { const: 1 }, │
| Type.Literal(2), │ │ { const: 2 }, │
| Type.Literal(3) │ │ { const: 3 } │
│ ]) │ │ ], │
│ const T = Type.Tuple([ │ │ additionalItems: false, │
| ...Type.Rest(A), │ │ minItems: 4, │
| ...Type.Test(B) │ │ maxItems: 4 │
│ ]) │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({ │ type T = { │ const R = { │
│ x: Type.Number(), │ x: number, │ $ref: 'T' │
│ y: Type.Number() │ y: number │ } │
│ }, { $id: 'T' }) | } │ │
│ │ │ │
│ const R = Type.Ref(T) │ type R = T │ │
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘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.
┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ 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' │
│ │ │ } │
│ │ │ │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘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.
┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ 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' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘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 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 | nullReference 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 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: {
// $ref: 'Node'
// }
// }
// },
// required: [
// 'id',
// 'nodes'
// ]
// }
type Node = Static<typeof Node> // type Node = {
// id: string
// nodes: Node[]
// }
function test(node: Node) {
const id = node.nodes[0].nodes[0].id // id is string
}Conditional types are supported with Type.Extends, Type.Exclude and Type.Extract
// TypeScript
type T0 = string extends number ? true : false // type T0 = false
type T1 = Extract<string | number, number> // type T1 = number
type T2 = Exclude<string | number, number> // type T2 = string
// TypeBox
const T0 = Type.Extends(Type.String(), Type.Number(), Type.Literal(true), Type.Literal(false))
const T1 = Type.Extract(Type.Union([Type.String(), Type.Number()]), Type.Number())
const T2 = Type.Exclude(Type.Union([Type.String(), Type.Number()]), Type.Number())
type T0 = Static<typeof T0> // type T0 = false
type T1 = Static<typeof T1> // type T1 = number
type T2 = Static<typeof T2> // type T2 = stringTypeBox supports Template Literal types using Type.TemplateLiteral. These types can be created using a simple template DSL syntax, however more complex template literals can be created by passing an array of literal and union types. The examples below show the template DSL syntax.
// TypeScript
type P = `/post/${string}/user/${number}` // type P = `/post/${string}/user/${number}`
type T = `option${'A'|'B'}` // type T = 'optionA' | 'optionB'
type R = Record<T, string> // type R = {
// optionA: string
// optionB: string
// }
// TypeBox
const P = Type.TemplateLiteral('/post/${string}/user/${number}')
// const P = {
// type: 'string',
// pattern: '^/post/(.*)/user/(0|[1-9][0-9]*)$'
// }
const T = Type.TemplateLiteral('option${A|B}') // const T = {
// pattern: '^option(A|B)$',
// type: 'string'
// }
const R = Type.Record(T, Type.String()) // const R = {
// type: 'object',
// required: ['optionA', 'optionB'],
// properties: {
// optionA: {
// type: 'string'
// },
// optionB: {
// type: 'string'
// }
// }
// }TypeBox supports Indexed Access types using Type.Index. This feature provides a consistent way to access property types without having to extract them from the underlying schema representation. Indexed accessors are supported for object and tuples, as well as nested union and intersect types.
const T = Type.Object({ // const T = {
x: Type.Number(), // type: 'object',
y: Type.String(), // required: ['x', 'y', 'z'],
z: Type.Boolean() // properties: {
}) // x: { type: 'number' },
// y: { type: 'string' },
// z: { type: 'string' },
// }
// }
const A = Type.Index(T, ['x']) // const A = { type: 'number' }
const B = Type.Index(T, ['x', 'y']) // const B = {
// anyOf: [
// { type: 'number' },
// { type: 'string' }
// ]
// }
const C = Type.Index(T, Type.KeyOf(T)) // const C = {
// anyOf: [
// { type: 'number' },
// { type: 'string' },
// { type: 'boolean' }
// ]
// }Rest parameters are supported with Type.Rest. This function is used to extract interior type elements from tuples which enables them to compose with the JavaScript spread operator .... This type can be used for tuple concatination as well as for variadic functions.
// TypeScript
type T = [number, number] // type T = [number, number]
type C = [...T, number] // type C = [number, number, number]
type F = (...param: C) => void // type F = (
// param0: number,
// param1: number,
// param2: number,
// ) => void
// TypeBox
const T = Type.Tuple([ // const T: TTuple<[
Type.Number(), // TNumber,
Type.Number() // TNumber,
]) // ]>
const C = Type.Tuple([ // const C: TTuple<[
...Type.Rest(T), // TNumber,
Type.Number() // TNumber,
]) // TNumber
// ]>
const F = Type.Function(Type.Rest(C), Type.Void()) // const F: TFunction<[
// TNumber,
// TNumber,
// TNumber
// ], TVoid>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 = stringThe 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'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
}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'
// }
// }
// }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'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 }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 }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 = trueUse the Convert function to convert a value into its target type if a reasonable conversion is possible.
const T = Type.Object({ x: 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' }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 }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 }
)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 = 1418369778807423581nUse 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' }
// ]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 }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'
// }]Use the Mutate function to perform a deep mutable value assignment while retaining internal references.
const Y = { z: 1 } // const Y = { z: 1 }
const X = { y: Y } // const X = { y: { z: 1 } }
const A = { x: X } // const A = { x: { y: { z: 1 } } }
Value.Mutate(A, { x: { y: { z: 2 } } }) // const A' = { x: { y: { z: 2 } } }
const R0 = A.x.y.z === 2 // const R0 = true
const R1 = A.x.y === Y // const R1 = true
const R2 = A.x === X // const R2 = trueUse 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 }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.
The following shows the recommended setup for Ajv.
$ npm install ajv ajv-formats --saveimport { 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 = trueThe 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. Note that compilation is an expensive operation that should typically be performed once per type during application start up. TypeBox does not cache previously compiled types, so applications are expected to hold references to each compiled type for the lifetime of the application.
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 = trueUse 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')
// )
// }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'Use the Type(...) function to create custom types. This function lets you specify custom value assertion logic and will return a type factory function which is used to instance the type. This function accepts two generic arguments, the first is the inference type, the second is options used to constrain the type. The following creates a Vector type.
type VectorOptions = { abs: boolean }
type Vector = { x: number, y: number }
const Vector = TypeSystem.Type<Vector, VectorOptions>('Vector', (options, value) => {
return (
typeof value === 'object' && value !== null &&
'x' in value && typeof value.x === 'number' &&
'y' in value && typeof value.y === 'number' &&
(options.abs ? (value.x === Math.abs(value.x) && value.y === Math.abs(value.y)) : true)
)
})
const T = Vector({ abs: true })
type T = Static<typeof T> // type T = Vector
const R1 = Value.Check(T, { x: 1, y: 1 }) // const R1 = true
const R2 = Value.Check(T, { x: 1, y: '1' }) // const R2 = false
const R3 = Value.Check(T, { x: 1, y: -1 }) // const R3 = falseUse the Format(...) function to create a custom string format. The following creates a 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, 'Hello') // const A = false
const B = Value.Check(T, 'hello') // const B = trueTypeBox validates using standard JSON Schema assertion policies by default. It is possible to override some of these policies to have TypeBox assert inline with TypeScript static assertion rules. The following policy overrides are available.
// Disallow undefined values for optional properties (default is false)
//
// const A: { x?: number } = { x: undefined } - disallowed when enabled
TypeSystem.ExactOptionalPropertyTypes = true
// 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 = trueTypeBox offers a small web based code generation tool that can be used to convert TypeScript types into TypeBox type definitions as well as a variety of other formats.
The following is a list of community packages that provide general tooling and framework support for TypeBox.
| Package | Description |
|---|---|
| elysia | Fast and friendly Bun web framework |
| fastify-type-provider-typebox | Fastify TypeBox integration with the Fastify Type Provider |
| fetch-typebox | Drop-in replacement for fetch that brings easy integration with TypeBox |
| schema2typebox | Creating TypeBox code from JSON schemas |
| ts2typebox | Creating TypeBox code from Typescript types |
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 8.12.0 running on Node 20.0.0.
For additional comparative benchmarks, please refer to typescript-runtime-type-benchmarks.
This benchmark measures compilation performance for varying types. You can review this benchmark here.
┌────────────────────────────┬────────────┬──────────────┬──────────────┬──────────────┐
│ (index) │ Iterations │ Ajv │ TypeCompiler │ Performance │
├────────────────────────────┼────────────┼──────────────┼──────────────┼──────────────┤
│ Literal_String │ 1000 │ ' 230 ms' │ ' 7 ms' │ ' 32.86 x' │
│ Literal_Number │ 1000 │ ' 171 ms' │ ' 4 ms' │ ' 42.75 x' │
│ Literal_Boolean │ 1000 │ ' 148 ms' │ ' 4 ms' │ ' 37.00 x' │
│ Primitive_Number │ 1000 │ ' 160 ms' │ ' 6 ms' │ ' 26.67 x' │
│ Primitive_String │ 1000 │ ' 149 ms' │ ' 6 ms' │ ' 24.83 x' │
│ Primitive_String_Pattern │ 1000 │ ' 199 ms' │ ' 9 ms' │ ' 22.11 x' │
│ Primitive_Boolean │ 1000 │ ' 126 ms' │ ' 3 ms' │ ' 42.00 x' │
│ Primitive_Null │ 1000 │ ' 141 ms' │ ' 4 ms' │ ' 35.25 x' │
│ Object_Unconstrained │ 1000 │ ' 1105 ms' │ ' 27 ms' │ ' 40.93 x' │
│ Object_Constrained │ 1000 │ ' 1178 ms' │ ' 22 ms' │ ' 53.55 x' │
│ Object_Vector3 │ 1000 │ ' 368 ms' │ ' 8 ms' │ ' 46.00 x' │
│ Object_Box3D │ 1000 │ ' 1668 ms' │ ' 28 ms' │ ' 59.57 x' │
│ Tuple_Primitive │ 1000 │ ' 446 ms' │ ' 12 ms' │ ' 37.17 x' │
│ Tuple_Object │ 1000 │ ' 1146 ms' │ ' 15 ms' │ ' 76.40 x' │
│ Composite_Intersect │ 1000 │ ' 661 ms' │ ' 18 ms' │ ' 36.72 x' │
│ Composite_Union │ 1000 │ ' 513 ms' │ ' 17 ms' │ ' 30.18 x' │
│ Math_Vector4 │ 1000 │ ' 767 ms' │ ' 10 ms' │ ' 76.70 x' │
│ Math_Matrix4 │ 1000 │ ' 396 ms' │ ' 10 ms' │ ' 39.60 x' │
│ Array_Primitive_Number │ 1000 │ ' 353 ms' │ ' 8 ms' │ ' 44.13 x' │
│ Array_Primitive_String │ 1000 │ ' 358 ms' │ ' 5 ms' │ ' 71.60 x' │
│ Array_Primitive_Boolean │ 1000 │ ' 265 ms' │ ' 3 ms' │ ' 88.33 x' │
│ Array_Object_Unconstrained │ 1000 │ ' 1476 ms' │ ' 19 ms' │ ' 77.68 x' │
│ Array_Object_Constrained │ 1000 │ ' 1698 ms' │ ' 20 ms' │ ' 84.90 x' │
│ Array_Tuple_Primitive │ 1000 │ ' 654 ms' │ ' 9 ms' │ ' 72.67 x' │
│ Array_Tuple_Object │ 1000 │ ' 1492 ms' │ ' 15 ms' │ ' 99.47 x' │
│ Array_Composite_Intersect │ 1000 │ ' 1045 ms' │ ' 16 ms' │ ' 65.31 x' │
│ Array_Composite_Union │ 1000 │ ' 702 ms' │ ' 14 ms' │ ' 50.14 x' │
│ Array_Math_Vector4 │ 1000 │ ' 1016 ms' │ ' 12 ms' │ ' 84.67 x' │
│ Array_Math_Matrix4 │ 1000 │ ' 621 ms' │ ' 5 ms' │ ' 124.20 x' │
└────────────────────────────┴────────────┴──────────────┴──────────────┴──────────────┘This benchmark measures validation performance for varying types. You can review this benchmark here.
┌────────────────────────────┬────────────┬──────────────┬──────────────┬──────────────┬──────────────┐
│ (index) │ Iterations │ ValueCheck │ Ajv │ TypeCompiler │ Performance │
├────────────────────────────┼────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
│ Literal_String │ 1000000 │ ' 22 ms' │ ' 5 ms' │ ' 4 ms' │ ' 1.25 x' │
│ Literal_Number │ 1000000 │ ' 19 ms' │ ' 17 ms' │ ' 9 ms' │ ' 1.89 x' │
│ Literal_Boolean │ 1000000 │ ' 18 ms' │ ' 17 ms' │ ' 9 ms' │ ' 1.89 x' │
│ Primitive_Number │ 1000000 │ ' 23 ms' │ ' 17 ms' │ ' 9 ms' │ ' 1.89 x' │
│ Primitive_String │ 1000000 │ ' 23 ms' │ ' 18 ms' │ ' 9 ms' │ ' 2.00 x' │
│ Primitive_String_Pattern │ 1000000 │ ' 171 ms' │ ' 42 ms' │ ' 36 ms' │ ' 1.17 x' │
│ Primitive_Boolean │ 1000000 │ ' 20 ms' │ ' 17 ms' │ ' 9 ms' │ ' 1.89 x' │
│ Primitive_Null │ 1000000 │ ' 21 ms' │ ' 16 ms' │ ' 8 ms' │ ' 2.00 x' │
│ Object_Unconstrained │ 1000000 │ ' 1099 ms' │ ' 31 ms' │ ' 25 ms' │ ' 1.24 x' │
│ Object_Constrained │ 1000000 │ ' 1224 ms' │ ' 51 ms' │ ' 36 ms' │ ' 1.42 x' │
│ Object_Vector3 │ 1000000 │ ' 420 ms' │ ' 22 ms' │ ' 13 ms' │ ' 1.69 x' │
│ Object_Box3D │ 1000000 │ ' 2012 ms' │ ' 53 ms' │ ' 43 ms' │ ' 1.23 x' │
│ Object_Recursive │ 1000000 │ ' 5080 ms' │ ' 320 ms' │ ' 150 ms' │ ' 2.13 x' │
│ Tuple_Primitive │ 1000000 │ ' 154 ms' │ ' 20 ms' │ ' 12 ms' │ ' 1.67 x' │
│ Tuple_Object │ 1000000 │ ' 749 ms' │ ' 27 ms' │ ' 18 ms' │ ' 1.50 x' │
│ Composite_Intersect │ 1000000 │ ' 775 ms' │ ' 24 ms' │ ' 14 ms' │ ' 1.71 x' │
│ Composite_Union │ 1000000 │ ' 533 ms' │ ' 22 ms' │ ' 13 ms' │ ' 1.69 x' │
│ Math_Vector4 │ 1000000 │ ' 275 ms' │ ' 20 ms' │ ' 11 ms' │ ' 1.82 x' │
│ Math_Matrix4 │ 1000000 │ ' 1136 ms' │ ' 37 ms' │ ' 26 ms' │ ' 1.42 x' │
│ Array_Primitive_Number │ 1000000 │ ' 316 ms' │ ' 20 ms' │ ' 12 ms' │ ' 1.67 x' │
│ Array_Primitive_String │ 1000000 │ ' 239 ms' │ ' 20 ms' │ ' 12 ms' │ ' 1.67 x' │
│ Array_Primitive_Boolean │ 1000000 │ ' 151 ms' │ ' 20 ms' │ ' 15 ms' │ ' 1.33 x' │
│ Array_Object_Unconstrained │ 1000000 │ ' 5809 ms' │ ' 64 ms' │ ' 56 ms' │ ' 1.14 x' │
│ Array_Object_Constrained │ 1000000 │ ' 6210 ms' │ ' 123 ms' │ ' 101 ms' │ ' 1.22 x' │
│ Array_Object_Recursive │ 1000000 │ ' 21779 ms' │ ' 1466 ms' │ ' 548 ms' │ ' 2.68 x' │
│ Array_Tuple_Primitive │ 1000000 │ ' 730 ms' │ ' 36 ms' │ ' 29 ms' │ ' 1.24 x' │
│ Array_Tuple_Object │ 1000000 │ ' 3259 ms' │ ' 63 ms' │ ' 49 ms' │ ' 1.29 x' │
│ Array_Composite_Intersect │ 1000000 │ ' 3276 ms' │ ' 44 ms' │ ' 34 ms' │ ' 1.29 x' │
│ Array_Composite_Union │ 1000000 │ ' 2279 ms' │ ' 64 ms' │ ' 31 ms' │ ' 2.06 x' │
│ Array_Math_Vector4 │ 1000000 │ ' 1139 ms' │ ' 36 ms' │ ' 23 ms' │ ' 1.57 x' │
│ Array_Math_Matrix4 │ 1000000 │ ' 4924 ms' │ ' 110 ms' │ ' 92 ms' │ ' 1.20 x' │
└────────────────────────────┴────────────┴──────────────┴──────────────┴──────────────┴──────────────┘The following table lists esbuild compiled and minified sizes for each TypeBox module.
┌──────────────────────┬────────────┬────────────┬─────────────┐
│ (index) │ Compiled │ Minified │ Compression │
├──────────────────────┼────────────┼────────────┼─────────────┤
│ typebox/compiler │ '128.0 kb' │ ' 56.9 kb' │ '2.25 x' │
│ typebox/errors │ '111.6 kb' │ ' 49.1 kb' │ '2.27 x' │
│ typebox/system │ ' 77.0 kb' │ ' 31.5 kb' │ '2.45 x' │
│ typebox/value │ '177.7 kb' │ ' 76.8 kb' │ '2.31 x' │
│ typebox │ ' 75.9 kb' │ ' 31.0 kb' │ '2.45 x' │
└──────────────────────┴────────────┴────────────┴─────────────┘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.
