Home API Guides GitHub|EN NL

Core

define
equals
logic
parse
assert
nullish
key
primitive
object
predicate
types

Combinators

arrayOf
tupleOf
setOf
mapOf
oneOf
recordOf
struct
typedStruct
oneOfValues

Guides

Filter nullish values
Sync type guards
Validate unknown

Home API Guides GitHub EN NL

Loading docs…

API Reference

Explore the available functions, combinators, and public types. Use the sidebar to navigate.

Wrap a predicate as a typed guard.

Value equality helpers: equals, equalsBy, equalsKey.

Logical combinators: and, andAll, or, not, guardIn.

Guard values or decode and validate JSON with tagged results.

Fail-fast assertion helper with type narrowing.

Nullability helpers: isNil, isNotNil, nullable, optional, required, nonNull.

Key helpers for presence checks (hasKey/hasKeys) and literal narrowing.

Primitive guards: string, number, boolean, nullish, etc.

Object and built-in guards: array, date, map, set, isInstanceOf, …

Convert boolean predicates to refinements.

Public type contracts for guards, parsing, schemas, and reusable wrappers.

Guard arrays with an element guard.

Guard fixed-length tuples by position.

Guard sets with a value guard.

Guard maps with key and value guards.

Passes when any guard passes (union).

Guard records with key and value guards.

Shape guard for objects; supports exact key checking.

Typed struct wrapper that checks fields against an existing object type.

Guard literal value sets with exact equality.