detectSeparator.js

function detectSeparator(input) {
  const availableSeparators = [ ';', ',', '|' ];
  const separatorCount = availableSeparators.map((separator) => occurrences(input, separator));

  return R.transpose([ availableSeparators, separatorCount ])
    .reduce((maxSeparator, separator) => {
      return separator[1] > maxSeparator[1] ? separator : maxSeparator;
    }, [ availableSeparators[0], -1 ])[0];
}