getNumberOfStars

getNumberOfStars.js

// Fixtures
const FILLED_STAR = '<filled/>';
const EMPTY_STAR = '<empty/>';
const MAX_STARS = 5;
const numberOfStars = 3;

// Version 1

R.join('',
  R.concat(
    R.times(R.always(FILLED_STAR), numberOfStars),
    R.times(R.always(EMPTY_STAR), R.subtract(MAX_STARS, numberOfStars))
  )
)

// Version 2

// getFilledStars :: Number -> [String]
const getFilledStars = R.times(R.always(FILLED_STAR));

// getEmptyStars :: Number -> [String]
const getEmptyStars = numberOfStars => R.times(
  R.always(EMPTY_STAR),
  R.subtract(MAX_STARS, numberOfStars)
);

// getNumberOfStars :: Number -> String
const getNumberOfStars = R.pipe(
  R.converge(R.concat, [getFilledStars, getEmptyStars]),
  R.join('')
);

getNumberOfStars(numberOfStars);