Message from JavaScript discussions

function wordWrap(input, maxLen, wordSep = ' ', lineDelim = '\n') {
  if (
    typeof input !== 'string' ||
    input.length < maxLen
  ) {
    return input;
  }

  const lines = [];

  const lastLine = input.split(wordSep).reduce((line, word) => {
    line.push(word);
    if (line.join(wordSep).length > maxLen) {
      const next = line.pop(word);
      lines.push(line);
      return [ next ];
    }
    return line;
  }, []);

  if (lastLine.length > 0) {
    lines.push(lastLine);
  }

  return lines.map(line => line.join(wordSep)).join(lineDelim);
}