Practice string methods:
let email = " User@Example.COM "
// Clean and normalize
let cleaned = email.trim().toLowerCase()
console.log(cleaned) // "user@example.com"
// Extract parts
let [username, domain] = cleaned.split("@")
console.log(username) // "user"
console.log(domain) // "example.com"
// Validate
console.log(cleaned.includes("@")) // true
console.log(domain.endsWith(".com")) // true