Convert between hex and rgb colour values using Ramda

hexToRgbToHex.js

import { __, compose, concat, join,
        map, match, propEq, replace,
        splitEvery, unnest, when } from "ramda";

/*
 * USAGE
 * let hex = '#fff54a'
 * let rgb = 'rgb(255,245,74)'
 * rgbToHex(rgb) // #fff54a
 * hexToRgb(hex) // rgb(255,245,74)
 */

const toHex = x => x.toString(16);
const fromHex = x => parseInt(x, 16);
const strToNum = x => parseInt(x, 10);

const duplicate = unnest(concat)
const normalize = when(propEq("length", 1), duplicate);
const strToHex = compose(normalize, toHex, strToNum);
const wrapRgb = compose(
  concat(__, ")"),
  concat("rgb(")
);

export const rgbToHex = compose(
  concat("#"),
  join(""),
  map(strToHex),
  match(/(\d{1,3})/g)
);

export const hexToRgb = compose(
  wrapRgb,
  join(","),
  map(fromHex),
  splitEvery(2),
  replace(/^#/, "")
);

Link to Ramda REPL with this code

There are more efficient ways to do this.