typebox/codegen/typebox-to-typescript.ts

/*--------------------------------------------------------------------------

@sinclair/typebox/codegen

The MIT License (MIT)

Copyright (c) 2017-2023 Haydn Paterson (sinclair) <haydn.developer@gmail.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

---------------------------------------------------------------------------*/

import { Formatter } from './formatter'
import * as Types from '@sinclair/typebox'

export namespace TypeBoxToTypeScript {
  function Any(schema: Types.TAny) {
    return 'any'
  }
  function Array(schema: Types.TArray) {
    const items = Visit(schema.items)
    return `Array<${items}>`
  }
  function Boolean(schema: Types.TBoolean) {
    return 'boolean'
  }
  function Constructor(schema: Types.TConstructor) {
    const params = schema.parameters.map((param) => Visit(param)).join(', ')
    const returns = Visit(schema.returns)
    return `new (${params}) => ${returns}`
  }
  function Function(schema: Types.TFunction) {
    const params = schema.parameters.map((param) => Visit(param)).join(', ')
    const returns = Visit(schema.returns)
    return `(${params}) => ${returns}`
  }
  function Integer(schema: Types.TInteger) {
    return 'number'
  }
  function Intersect(schema: Types.TIntersect) {
    return `(${schema.allOf.map((schema) => Visit(schema)).join(' & ')})`
  }
  function Literal(schema: Types.TLiteral) {
    if (typeof schema.const === 'string') {
      return `'${schema.const}'`
    } else {
      return `${schema.const}`
    }
  }
  function Never(schema: Types.TNever) {
    return 'never'
  }
  function Null(schema: Types.TNull) {
    return 'null'
  }
  function String(schema: Types.TString) {
    return 'string'
  }
  function Number(schema: Types.TNumber) {
    return 'number'
  }
  function Object(schema: Types.TObject) {
    const properties: string = globalThis.Object.entries(schema.properties)
      .map(([key, value]) => {
        return `${key}: ${Visit(value)}`
      })
      .join(',\n')
    return `{\n${properties}\n}`
  }
  function Promise(schema: Types.TPromise) {
    const item = Visit(schema.item)
    return `Promise<${item}>`
  }
  function Record(schema: Types.TRecord) {
    for (const [key, value] of globalThis.Object.entries(schema.patternProperties)) {
      const type = Visit(value)
      if (key === '^(0|[1-9][0-9]*)$') {
        return `Record<number, ${type}>`
      } else {
        return `Record<string, ${type}>`
      }
    }
    throw Error('TypeBoxToTypeScript: Unreachable')
  }
  function Ref(schema: Types.TRef) {
    return schema.$ref
  }
  function Self(schema: Types.TSelf) {
    return schema.$ref
  }
  function Tuple(schema: Types.TTuple) {
    if (schema.items === undefined) return `[]`
    const items = schema.items.map((schema) => Visit(schema)).join(', ')
    return `[${items}]`
  }
  function UInt8Array(schema: Types.TUint8Array) {
    return `Uint8Array`
  }
  function Undefined(schema: Types.TUndefined) {
    return `undefined`
  }
  function Union(schema: Types.TUnion) {
    return `${schema.anyOf.map((schema) => Visit(schema)).join(' | ')}`
  }
  function Unknown(schema: Types.TUnknown) {
    return `unknown`
  }
  function Void(schema: Types.TVoid) {
    return `void`
  }
  function Visit(schema: Types.TSchema): string {
    if (Types.TypeGuard.TAny(schema)) {
      return Any(schema)
    } else if (Types.TypeGuard.TArray(schema)) {
      return Array(schema)
    } else if (Types.TypeGuard.TBoolean(schema)) {
      return Boolean(schema)
    } else if (Types.TypeGuard.TConstructor(schema)) {
      return Constructor(schema)
    } else if (Types.TypeGuard.TFunction(schema)) {
      return Function(schema)
    } else if (Types.TypeGuard.TInteger(schema)) {
      return Integer(schema)
    } else if (Types.TypeGuard.TIntersect(schema)) {
      return Intersect(schema)
    } else if (Types.TypeGuard.TLiteral(schema)) {
      return Literal(schema)
    } else if (Types.TypeGuard.TNever(schema)) {
      return Never(schema)
    } else if (Types.TypeGuard.TNull(schema)) {
      return Null(schema)
    } else if (Types.TypeGuard.TNumber(schema)) {
      return Number(schema)
    } else if (Types.TypeGuard.TObject(schema)) {
      return Object(schema)
    } else if (Types.TypeGuard.TPromise(schema)) {
      return Promise(schema)
    } else if (Types.TypeGuard.TRecord(schema)) {
      return Record(schema)
    } else if (Types.TypeGuard.TRef(schema)) {
      return Ref(schema)
    } else if (Types.TypeGuard.TSelf(schema)) {
      return Self(schema)
    } else if (Types.TypeGuard.TString(schema)) {
      return String(schema)
    } else if (Types.TypeGuard.TTuple(schema)) {
      return Tuple(schema)
    } else if (Types.TypeGuard.TUint8Array(schema)) {
      return UInt8Array(schema)
    } else if (Types.TypeGuard.TUndefined(schema)) {
      return Undefined(schema)
    } else if (Types.TypeGuard.TUnion(schema)) {
      return Union(schema)
    } else if (Types.TypeGuard.TUnknown(schema)) {
      return Unknown(schema)
    } else if (Types.TypeGuard.TVoid(schema)) {
      return Void(schema)
    } else {
      throw Error('TypeBoxToTypeScript: Unknown type')
    }
  }
  /** Generates TypeScript code from TypeBox types */
  export function Generate(schema: Types.TSchema, references: Types.TSchema[] = []) {
    const result: string[] = []
    for (const reference of references) {
      result.push(`type ${reference.$id} = ${[...Visit(reference)].join('')}`)
    }
    result.push(`type ${schema.$id || 'T'} = ${[...Visit(schema)].join('')}`)
    return Formatter.Format(result.join('\n\n'))
  }
}