const names = ['Ali', 'Atta', 'Alex', 'John'];
const uppercased = names.map(name => name.toUpperCase());
console.log(uppercased);
// ['ALI', 'ATTA', 'ALEX', 'JOHN']
let txt = "Hello World!";
txt = txt.toUpperCase();
string a = "String";
string b = a.Replace("i", "o"); // Strong
b = a.Insert(0, "My "); // My String
b = a.Remove(0, 3); // ing
b = a.Substring(0, 3); // Str
b = a.ToUpper(); // STRING
int i = a.Length; // 6