Bonfire: Truncate a string

My low bro solution, it's ugly, and still took me time...

function truncate(str, num) {
  
  if(num <= 3){
    return str.slice(0,num) + "...";
  }
   if(str.length > num){
    return str.slice(0,num-3) + "...";
  }
   if(num >= str.length){
    return str;
  }
}

truncate("A-tisket a-tasket A green and yellow basket", 2);

It took me time because I literally translated this instructions "If the length of the string is less than or equal to 3 characters" as this:

  if(str.length <= 3){
    return str.slice(0,num) + "...";
  }

instead of course, of this:

  if(num <= 3){
    return str.slice(0,num) + "...";
  }

akshat01 posted this on Gitter in the HelpBonfires room and it's way more concise:

function truncate(str, num) {

  var i= 0;
  if (num >=3){
    i=3;
  }

  if (str.length> num){
    str= str.slice(0,num-i)+"...";}
  return str;
} 

truncate("A-tisket a-tasket A green and yellow basket", 1);

I don't know what it says about me but it took me a good 15 mins to understand the logic of just returning the str as is, in fact the default value since both "if" statements covered all other cases