until transducer: composition

compose.test.ts

import { double_sum2_to_string } from './compose'

test('stringify after add 2 after double', () => {

  expect(double_sum2_to_string([1, 2, 3])).toEqual(['4', '6', '8'])

})

compose.ts

import { compose, map } from 'ramda'

export const double_sum2_to_string =
  compose(
    map((number: number) => String(number)),
    map((number: number) => number + 2),
    map((number: number) => number * 2)
  )