moy-fp/test/Object/over.test.js

A functional programming library.

import __ from '../../src/Function/__'
import lensProp from '../../src/Object/lensProp'
/**
 * Lens s a -> (a -> a) -> s -> s
 * Lens s a = Functor f => (a -> f a) -> s -> f s  
 */
import over from '../../src/Object/over'

test('over(not using __)', () => {
  expect(
    over(lensProp('a'))(x => x + 1)({a: 1})
  ).toEqual({a: 2})
})

test('over(using __)', () => {
  expect(
    over(lensProp('a'), __, {a: 1})(x => x + 1)
  ).toEqual({a: 2})
})