Transform 12-Hour format to 24 hour. Run: https://repl.it/Gvco/2

transformPMHourToNormal.js

const {
  pipe, match, drop, head, range, map, identity, add
  , equals, last, join, take, ifElse, adjust, always
} = require('ramda')
const leftPad = require('left-pad')
const leftPadZero = size => x => leftPad(x, size, '0')

const clockToFullHours =
  pipe(
    match(/^(\d{1,2}):(\d{2})(\w{2})$/i)
  , drop(1)
  , ifElse(pipe(last, equals('pm')))
          (ifElse(pipe(head, equals('12')))
                 (adjust(always(0), 0))
                 (adjust(add(12), 0)))
          (identity)
  , take(2)
  , map(leftPadZero(2))
  , join(':')
  )

console.log(
  pipe(
    map(h => [`${h}:00am`, `${h}:00pm`])
  , map(map(clockToFullHours)
  )
  )(range(0, 13))  
)