Type validations

Type validations is a library for creating type-validators: augmented type-guards that perform full runtime type-validation and let TypeScript type checker know what a type may be in a certain context.

Installation

$ npm install @altostra/type-validations

Reference

A full reference can be found here.

allOf

Creates type-validators for an intersections-type from a list of type-validators.

anyOf

Creates type-validators for a union-type from a list of type-validators.

arrayOf

Given type-guard for type T, creates a type-validator for T[].

assertBy

Create assertion-functions from type-validation and an error-factory.

enumOf

Creates a type-validation that checks if a value is one of the specified values (using strict equality).

is

Creates a type-validation that only allows values that are strictly equal to the provided value.

isEmptyArray

A type-validation that checks if a value is an empty array.

isEmptyObject

A type-validation that checks if a value is an empty object.

isFunction

Creates a type-validation that checks if a value is a function with a specified length.

maybe

Creates a type-validation that checks if a value is of validated type, undefined, and optionally null.

objectOf

Creates type-validation that checks if a value is an object that all its properties are validated with the provided validations.

recordOf

Creates type-validator that checks that a given value is an object and that all its own-enumerable properties are of a specified type.

singleOrArray

Creates a type-validation that checks if a value is either a specific type or an array of that type.

taggedUnionOf

Creates type-validators for a union-type from a mapping between specified tag property values and validators, when the union-type is in fact a discriminated union.

tupleOf

Creates a type-validation that checks that an object is an array with a specific length, and has all the provided indices validated.

Primitives

Type-validations

• string
• maybeString
• number
• maybeNumber
• boolean
• maybeBoolean
• nullValidation
• nullOrUndefined
• undefinedValidation
• symbol
• maybeSymbol
• bigint
• maybeBigint
• any
• unknown
• never

Type-assertions

• stringAssertion
• maybeStringAssertion
• numberAssertion
• maybeNumberAssertion
• booleanAssertion
• maybeBooleanAssertion
• nullAssertion
• nullOrUndefinedAssertion
• undefinedAssertion
• symbolAssertion
• maybeSymbolAssertion
• bigintAssertion
• maybeBigintAssertion
• anyAssertion
• unknownAssertion
• assert