moy-fp/test/Relation/minBy.test.js

A functional programming library.

import __ from '../../src/Function/__'
/**
 * Ord b => (a -> b) -> a -> a -> a
 */
import minBy from '../../src/Relation/minBy'

test('minBy(not using __), return first', () => {
  expect(
    minBy(x => x.id)({id: 1})({id: 2})
  ).toEqual({id: 1})
})

test('minBy(not using __), return second', () => {
  expect(
    minBy(x => x.id)({id: 2})({id: 1})
  ).toEqual({id: 1})
})

test('minBy(using __), return first', () => {
  expect(
    minBy(x => x.id, __, {id: 2})({id: 1})
  ).toEqual({id: 1})
})