javascript truncate string

const string = "Name".slice(0, 250).concat('...');
const string2 = "Name".substring(0, 250).concat('...');

const str = 'Mozilla';

console.log(str.substring(1, 3));
// expected output: "oz"

console.log(str.substring(2));
// expected output: "zilla"

var string = "ABCDEFG";
var truncString = string.substring(0, 3); //Only keep the first 3 characters
console.log(truncString); //output: "ABC"

function truncateString(str, num) {
 
  if (str.length > num) {
    return str.slice(0, num) + "...";
  } else {
    return str;
  }
}

truncateString("Lorem Ipsum placeholder text in any number of characters, words sentences or paragraphs", 9)  // returns Lorem Ips...