Dictionary

litetype API reference

Narrative lives in the guide. This page is the compact reference.

Verbs

`parse(s, data)`	Return `Infer<S>` or throw `SchemaError`
`safeParse(s, data)`	Return a success/error union
`check(s, data)`	Type predicate
`compile(s)`	Cached predicate for hot loops

Types

`Infer<S>`	Output type
`InferInput<S>`	Input type before transforms and defaults
`Schema<O, I>`	A schema node
`Shape`	A bare object schema

Leaves

Schema	Output	Checks
`string`	`string`	`min`, `max`, `length`, `email`, `url`, `uuid`, `datetime`, `ip`, `startsWith`, `endsWith`, `includes`, `regex`
`number`	`number`	`min`, `max`, `gt`, `lt`, `int`, `finite`, `positive`, `nonnegative`, `multipleOf`
`boolean`	`boolean`	—
`date`	`Date`	`min`, `max`
`unknown`	`unknown`	—
`literal(v)`	literal type	exact value
`enum_(values)`	value union	member

Every schema node

`.transform(fn)`	Map after successful validation
`.refine(pred, message)`	Add a predicate
`.default(value)`	Fill when input is `undefined`
`.undefinable()`	Allow `undefined`
`.nullable()`	Allow `null`
`.nullish()`	Allow both

Composition

arraytupleunionrecorddiscriminatedUnionlazystrictstrippartialrequiredpreprocessrefinecoercefallbackdescribestandard

TypeScript

import { array, discriminatedUnion, lazy, literal, number, string } from 'litetype'

const Shape = discriminatedUnion('type',
  { type: literal('circle'), radius: number },
  { type: literal('square'), side: number },
)

const Tree = { value: string, 'children?': array(lazy(() => Tree)) }

Errors

Every issue is { path, message, code }. Use flatten for forms, treeify for nested display, or prettify for text.

JSON Schema

TypeScript

import { fromJsonSchema, toJsonSchema } from 'litetype/jsonschema'

The subpath keeps JSON Schema code out of the main bundle. Transform, refine and preprocess cannot be serialized.