console.log(userName.toUpperCase()) // This is function ()
// Kalyan , index starts from 0
console.log(userName.slice(1,3)) // last index not included
console.log(userName.slice(1)) // if second is not given goes to end
console.log(userName.replace("kal","kir")) // replace , case sensitive
let friend = "pavan"
console.log(userName.concat("is good frined of ",friend , " !"))
let friend2 = " satish ";
console.log(friend2)
console.log(friend2.trim()) // removes spaces and newlines
// Others string methods are present in mdn string docs