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) => {

    if (word.length > 0) {
      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
    .filter(line => line.length > 0)
    .map(line => line.join(wordSep).trim())
    .join(lineDelim);
}