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Type Alias: Validator()<T, U, E>

Validator<T, U, E> = (value) => Validation<U, E>

Defined in: validation/types.ts:59

A function that validates a value and returns a Validation.

Validators can be composed using flatMap, validate, and other combinators to build complex validation logic from simple validators.

Type Parameters​

T​

T

The input type to validate

U​

U

The output type after validation (often same as T)

E​

E

The error type

Parameters​

value​

T

Returns​

Validation<U, E>

Example​

const minLength = (min: number): Validator<string, string, string> =>
  (value) => value.length >= min
    ? valid(value)
    : invalid(`Must be at least ${min} characters`)