Distinctive design. Powerful software.

1export function uniqueContacts(contacts) {
2  const byEmail = new Map();
3  for (const contact of contacts) {
4    const email = contact.email.trim().toLowerCase();
5    if (email && !byEmail.has(email)) {
6      byEmail.set(email, { ...contact, email });
7    }
8  }
9  return [...byEmail.values()];
10}
11
12const contacts = uniqueContacts([
13  { name: "Ada", email: "ada@example.com" },
14  { name: "Ada", email: " ADA@example.com " }
15]);
16console.log(contacts.length);