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Transform TypeScript types to io-ts runtime validator codecs
TypeScript JavaScript
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Converts TypeScript type and interface definitions into io-ts type validators.


As a script

$ npm install -g ts-to-io
$ ts-to-io file.ts


$ npx ts-to-io file.ts

From code

NOTE: The validator generation is not intended to be performed at runtime. You should first generate the validators locally and then include them in the program source.

import { getValidatorsFromString } from "ts-to-io"

const sourceString = `
  type Person = { name: string; age: number | null }

const validators = getValidatorsFromString(sourceString)


ts-to-io supports the following config options

Key CLI opt Default Description
followImports --follow-imports false output codecs for types declared in imported files
includeHeader --no-include-header true omit io-ts import from the output

Supported types

Type Supported TypeScript codec
string string t.string
number number t.number
boolean boolean t.boolean
null null t.null
undefined undefined t.undefined
void void t.void
any, unknown any, unknown t.unknown
array Array<A> t.array(A)
record Record<K, A> t.record(K, A)
object type { name: string } t.type({ name: t.string })
interface interface I { name: string } t.type({ name: t.string })
literal 'ABC' t.literal('ABC')
partial Partial<{ name: string }> t.partial({ name: t.string })
readonly Readonly<A> -
readonly array ReadonlyArray<A> -
tuple [ A, B ] t.tuple([ A, B ])
tuple with rest [ A, B, ...C ] -
union A | B t.union([ A, B ])
intersection A & B t.intersection([ A, B ])
keyof keyof M -
recursive type type Node = { children: Node[] } -
function type fn = () => string t.Function
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