moy-fp/test/List/find.test.js

A functional programming library.

import __ from '../../src/Function/__'
/**
 * (a -> Boolean) -> [a] -> a | undefined
 */
import find from '../../src/List/find'

test('find(not using __), satisfy pred', () => {
  expect(
    find(x => x === 3)([1, 2, 3, 4])
  ).toBe(3)
})

test('find(not using __), not satisfy pred', () => {
  expect(
    find(x => x === 5)([1, 2, 3, 4])
  ).toBeUndefined()
})

test('find(using __), satisfy pred', () => {
  expect(
    find(__, [1, 2, 3, 4])(x => x === 3)
  ).toBe(3)
})