comma-split.js

function groupByUndefined(col) {
  var ret = []
  var current = []
  for (var i = 0; i < col.length; i++) {
    if (typeof col[i] !== 'undefined') current.push(col[i])
    else {
      ret.push(current)
      current = []
    }
  }
  ret.push(current)
  return ret
}

function splitByComma(txt) {
  var matches = txt.split(/(\(.*?\))|,/)
  return groupByUndefined(matches).map(x => x.join('')).filter(x=>x)
}

// example:
splitByComma('some text, like this, is (inevitable, though) entered by, who\'d guess it, user!')
// becomes ["some text", " like this", " is (inevitable, though)", " entered by", " who'd guess it", " user!"]