fp-ts/es6/boolean.d.ts

Functional programming in TypeScript

/**
 * @since 2.2.0
 */
import { Lazy } from './function'
/**
 * Defines the fold over a boolean value.
 * Takes two thunks `onTrue`, `onFalse` and a `boolean` value.
 * If `value` is false, `onFalse()` is returned, otherwise `onTrue()`.
 *
 * @example
 * import { some, map } from 'fp-ts/Option'
 * import { pipe } from 'fp-ts/function'
 * import { fold } from 'fp-ts/boolean'
 *
 * assert.deepStrictEqual(
 *  pipe(
 *    some(true),
 *    map(fold(() => 'false', () => 'true'))
 *  ),
 *  some('true')
 * )
 *
 * @category destructors
 * @since 2.2.0
 */
export declare function fold<A>(onFalse: Lazy<A>, onTrue: Lazy<A>): (value: boolean) => A