var lastSpaceIndex = null;
var lastLineBreak = 0;

function checkLineLength (str) {
  var strLength = str.length;

  if(str.length === 0) {
    lastSpaceindex = 0;
    lastLineBreak = 0;
  }

  if (strLength % 30 === 0) {
    lastlineBreak = strLength;
    insertLineBreak(str, lastLineBreak);
  }
  console.log((strLength - lastLineBreak));
  if (((strLength - lastLineBreak) > 30)) {
    lastLineBreak = lastSpaceIndex;
    insertLineBreak(str, lastLineBreak - 1);
  }
  lastSpaceIndex = strLength;
}


function insertLineBreak (str, index) {
  var newStr = str.split("");
  newStr[index] = '\n';
  console.log(newStr.join(''))
}

document.addEventListener('keyup', function (evt) {
  if(evt.target.id === 'ta' && evt.keyCode === 13){
    lastLineBreak = evt.target.value.length;
  }
  if(evt.target.id === 'ta' && evt.keyCode === 32){
    checkLineLength(evt.target.value)
  }
})