Fetches contacts.

PhoneContacts.swift

import Contacts

class PhoneContacts {
    
    struct Contact {
        let givenName: String
        let middleName: String
        let familyName: String
        let phoneNumber: [String]
        let email: [String]
    }
    
    static func readAll() -> [Contact]? {
        let contactStore = CNContactStore()
        // Get all the containers
        var allContainers: [CNContainer] = []
        do {
            allContainers = try contactStore.containers(matching: nil)
        } catch let error {
            // Request Denied by user.
            print("Error fetching containers due to \(error.localizedDescription)")
            return nil
        }
        
        return getCNContacts(from: allContainers, contactStore: contactStore).map { contact -> Contact in
            let givenName = contact.givenName
            let middleName = contact.middleName
            let familyName = contact.familyName
            let email = getEmailAddress(from: contact.emailAddresses)
            let phoneNumber = getPhoneNumber(from: contact.phoneNumbers)
            return Contact(givenName: givenName, middleName: middleName, familyName: familyName, phoneNumber: phoneNumber, email: email)
        }
    }
    
    private static func getCNContacts(from containers: [CNContainer], contactStore: CNContactStore) -> [CNContact] {
        let keysToFetch = [
        CNContactFormatter.descriptorForRequiredKeys(for: .fullName),
        CNContactGivenNameKey,
        CNContactMiddleNameKey,
        CNContactFamilyNameKey,
        CNContactPhoneNumbersKey,
        CNContactEmailAddressesKey,
        ] as [Any]
        
        var results: [CNContact] = []
        // Iterate all containers and append their contacts to our results array
        for container in containers {
            let fetchPredicate = CNContact.predicateForContactsInContainer(withIdentifier: container.identifier)
            do {
                let containerResults = try contactStore.unifiedContacts(matching: fetchPredicate, keysToFetch: keysToFetch as! [CNKeyDescriptor])
                results.append(contentsOf: containerResults)
            } catch {
                print("Error fetching results for container")
            }
        }
        results.sort { (contact0, contact1) -> Bool in
            return contact0.givenName.lowercased() < contact1.givenName.lowercased()
        }
        return results
    }
    
    private static func getPhoneNumber(from numbers: [CNLabeledValue<CNPhoneNumber>]) -> [String] {
        return numbers.compactMap { $0.value.stringValue }
    }
    
    private static func getEmailAddress(from address: [CNLabeledValue<NSString>]) -> [String] {
        return address.compactMap { $0.value as String }
    }
}

Don't forget to add NSContactsUsageDescription to the Info.plist file.