JavaScript Smart Truncate String Wihout Breaking Words

function truncate(str, n, suffix = '..') {  if (str.length <= n) return str  const subString = str.substr(0, n-1)  return subString.substr(0, subString.lastIndexOf(' ')) + suffix}

const str = truncate("I live in Malaysia", 11)  // "I live in.."

String.prototype.truncate =  function( n, suffix = '...' ) {    if (this.length <= n) { return this; }    var subString = this.substr(0, n-1);    return subString.substr(0, subString.lastIndexOf(' ')) + suffix;  }

const str = "I live in Malaysia".truncate(11)