Answer:
const readline = require('readline-sync');
let reg = /^(\d{3})(\d{3})(\d{4})$/;
do {
let number = readline.question("Enter a phone number: ");
if (number === '999') {
process.exit();
}
var r = number.match(reg);
if (!r) console.log("That is not right.");
else {
console.log(`(${r[1]}) ${r[2]}-${r[3]}`);
}
} while (true);
Explanation:
This is a javascript solution using regular expressions.
