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

A functional programming library.

import __ from '../../src/Function/__'
/**
 * (a -> Boolean) -> [a] -> Number
 */
import findIndex from '../../src/List/findIndex'

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

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

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