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

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

/**
 * @since 0.5.0
 */
import * as t from 'io-ts'
/**
 * Returns a clone of the given codec that replace a nullable input with the given value `a`
 *
 * @example
 * import { fromNullable } from 'io-ts-types/lib/fromNullable'
 * import * as t from 'io-ts'
 * import { right } from 'fp-ts/lib/Either'
 * import { PathReporter } from 'io-ts/lib/PathReporter'
 *
 * const T = fromNullable(t.number, -1)
 *
 * assert.deepStrictEqual(T.decode(1), right(1))
 * assert.deepStrictEqual(T.decode(null), right(-1))
 * assert.deepStrictEqual(T.decode(undefined), right(-1))
 * assert.deepStrictEqual(PathReporter.report(T.decode('a')), ['Invalid value "a" supplied to : fromNullable(number)'])
 *
 * @since 0.5.0
 */
export declare function fromNullable<C extends t.Mixed>(codec: C, a: t.TypeOf<C>, name?: string): C