moy-fp/test/Function/curry.test.js

A functional programming library.

import __ from '../../src/Function/__'
/**
 * ((a, b, c, ..., m) -> n) -> ((a, b, c, ..., m) -> n)
 */
import curry from '../../src/Function/curry'

test('curry(not using __), the original arity is 0', () => {
  let fn = curry(() => 1)

  expect(fn.length).toBe(0)

  expect(
    fn()
  ).toBe(1)
})

test('curry(not using __), the original arity is 1', () => {
  let fn = curry(a => a)

  expect(fn.length).toBe(1)

  expect(
    fn(1)
  ).toBe(1)
})

test('curry(not using __), the original arities are 2', () => {
  let fn = curry((a, b) => a + b)

  expect(fn.length).toBe(2)

  fn = fn(1)

  expect(fn.length).toBe(1)

  expect(
    fn(2)
  ).toBe(3)
})

test('curry(not using __), the original arities are 3', () => {
  let fn = curry((a, b, c) => a + b + c)

  expect(fn.length).toBe(3)

  fn = fn(1)

  expect(fn.length).toBe(2)

  fn = fn(2)

  expect(fn.length).toBe(1)

  expect(
    fn(3)
  ).toBe(6)
})

test('curry(not using __), the original arities are 4', () => {
  let fn = curry((a, b, c, d) => a + b + c + d)

  expect(fn.length).toBe(4)

  fn = fn(1)

  expect(fn.length).toBe(3)

  fn = fn(2)

  expect(fn.length).toBe(2)

  fn = fn(3)

  expect(fn.length).toBe(1)

  expect(
    fn(4)
  ).toBe(10)
})

test('curry(not using __), the original arities are 5', () => {
  let fn = curry((a, b, c, d, e) => a + b + c + d + e)

  expect(fn.length).toBe(5)

  fn = fn(1)

  expect(fn.length).toBe(4)

  fn = fn(2)

  expect(fn.length).toBe(3)

  fn = fn(3)

  expect(fn.length).toBe(2)

  fn = fn(4)

  expect(fn.length).toBe(1)

  expect(
    fn(5)
  ).toBe(15)
})

test('curry(not using __), the original arities are 6', () => {
  let fn = curry((a, b, c, d, e, f) => a + b + c + d + e + f)

  expect(fn.length).toBe(6)

  fn = fn(1)

  expect(fn.length).toBe(5)

  fn = fn(2)

  expect(fn.length).toBe(4)

  fn = fn(3)

  expect(fn.length).toBe(3)

  fn = fn(4)

  expect(fn.length).toBe(2)

  fn = fn(5)

  expect(fn.length).toBe(1)

  expect(
    fn(6)
  ).toBe(21)
})

test('curry(not using __), the original arities are 7', () => {
  let fn = curry((a, b, c, d, e, f, g) => a + b + c + d + e + f + g)

  expect(fn.length).toBe(7)

  fn = fn(1)

  expect(fn.length).toBe(6)

  fn = fn(2)

  expect(fn.length).toBe(5)

  fn = fn(3)

  expect(fn.length).toBe(4)

  fn = fn(4)

  expect(fn.length).toBe(3)

  fn = fn(5)

  expect(fn.length).toBe(2)

  fn = fn(6)

  expect(fn.length).toBe(1)

  expect(
    fn(7)
  ).toBe(28)
})

test('curry(not using __), the original arities are 8', () => {
  let fn = curry((a, b, c, d, e, f, g, h) => a + b + c + d + e + f + g + h)

  expect(fn.length).toBe(8)

  fn = fn(1)

  expect(fn.length).toBe(7)

  fn = fn(2)

  expect(fn.length).toBe(6)

  fn = fn(3)

  expect(fn.length).toBe(5)

  fn = fn(4)

  expect(fn.length).toBe(4)

  fn = fn(5)

  expect(fn.length).toBe(3)

  fn = fn(6)

  expect(fn.length).toBe(2)

  fn = fn(7)

  expect(fn.length).toBe(1)

  expect(
    fn(8)
  ).toBe(36)
})

test('curry(not using __), the original arities are 9', () => {
  let fn = curry((a, b, c, d, e, f, g, h, i) => a + b + c + d + e + f + g + h + i)

  expect(fn.length).toBe(9)

  fn = fn(1)

  expect(fn.length).toBe(8)

  fn = fn(2)

  expect(fn.length).toBe(7)

  fn = fn(3)

  expect(fn.length).toBe(6)

  fn = fn(4)

  expect(fn.length).toBe(5)

  fn = fn(5)

  expect(fn.length).toBe(4)

  fn = fn(6)

  expect(fn.length).toBe(3)

  fn = fn(7)

  expect(fn.length).toBe(2)

  fn = fn(8)

  expect(fn.length).toBe(1)

  expect(
    fn(9)
  ).toBe(45)
})

test('curry(not using __), the original arities are 10', () => {
  let fn = curry((a, b, c, d, e, f, g, h, i, j) => a + b + c + d + e + f + g + h + i + j)

  expect(fn.length).toBe(10)

  fn = fn(1)

  expect(fn.length).toBe(9)

  fn = fn(2)

  expect(fn.length).toBe(8)

  fn = fn(3)

  expect(fn.length).toBe(7)

  fn = fn(4)

  expect(fn.length).toBe(6)

  fn = fn(5)

  expect(fn.length).toBe(5)

  fn = fn(6)

  expect(fn.length).toBe(4)

  fn = fn(7)

  expect(fn.length).toBe(3)

  fn = fn(8)

  expect(fn.length).toBe(2)

  fn = fn(9)

  expect(fn.length).toBe(1)

  expect(
    fn(10)
  ).toBe(55)
})

test('curry(not using __), the original arities are 11', () => {
  let fn = curry((a, b, c, d, e, f, g, h, i, j, k) => a + b + c + d + e + f + g + h + i + j + k)

  expect(fn.length).toBe(0)

  fn = fn(1)

  expect(fn.length).toBe(10)

  fn = fn(2)

  expect(fn.length).toBe(9)

  fn = fn(3)

  expect(fn.length).toBe(8)

  fn = fn(4)

  expect(fn.length).toBe(7)

  fn = fn(5)

  expect(fn.length).toBe(6)

  fn = fn(6)

  expect(fn.length).toBe(5)

  fn = fn(7)

  expect(fn.length).toBe(4)

  fn = fn(8)

  expect(fn.length).toBe(3)

  fn = fn(9)

  expect(fn.length).toBe(2)

  fn = fn(10)

  expect(fn.length).toBe(1)

  expect(
    fn(11)
  ).toBe(66)
})

test('curry(using __)', () => {
  expect(
    curry((x, y) => x + y)(__, 2)(1)
  ).toBe(3)
})