io-ts-types/lib/withMessage.d.ts

A collection of codecs and combinators for use with io-ts

/**
 * @since 0.4.3
 */
import * as t from 'io-ts'
/**
 * Returns a clone of the given codec that sets the given string as error messsage
 *
 * @example
 * import { withMessage } from 'io-ts-types/lib/withMessage'
 * import * as t from 'io-ts'
 * import { PathReporter } from 'io-ts/lib/PathReporter'
 * import { right } from 'fp-ts/lib/Either'
 *
 * const T = withMessage(t.number, () => 'Invalid number')
 *
 * assert.deepStrictEqual(T.decode(1), right(1))
 * assert.deepStrictEqual(PathReporter.report(T.decode(null)), ['Invalid number'])
 *
 * @since 0.4.3
 */
export declare function withMessage<C extends t.Any>(codec: C, message: (i: t.InputOf<C>, c: t.Context) => string): C