Pretty format number using '.toLocaleString()'
// Error
console.log(123456.toLocaleString()); // wont work
// Method 1: Store it in a variable
const n = 123456;
console.log(n.toLocaleString()); // 123,456
// Method 2: Use Number() to convert it into type Number
console.log(Number(12345).toLocaleString()); // 12,345