Optimize search in SwiftUI to load without lagging - arrays

Question

What will be the best way to optimize this swift code to filter without lagging. I have tried both appending and binding but still, it lags.
import Contacts
import SwiftUI
import Combine
class ContactStore: ObservableObject {
#Published var contacts: [ContactsModel] = []
var searchText: String = ""{
didSet {
self.fetchContacts()
}
}
init() {
self.fetchContacts()
}
private func fetchContacts() {
let store = CNContactStore()
store.requestAccess(for: .contacts) { (granted, error) in
if let error = error {
print("failed to request access", error)
return
}
if granted {
// print("access granted")
let keys = [CNContactGivenNameKey, CNContactFamilyNameKey, CNContactPhoneNumbersKey, CNContactBirthdayKey]
let keysToFetch = [CNContactGivenNameKey, CNContactFamilyNameKey, CNContactPhoneNumbersKey] as [CNKeyDescriptor]
let request = CNContactFetchRequest(keysToFetch: keys as [CNKeyDescriptor])
do {
if self.searchText.isEmpty {
try store.enumerateContacts(with: request, usingBlock: { (contact, stopPointer) in
self.contacts.append(ContactsModel(firstName: contact.givenName, lastName: contact.familyName, birthDay: contact.birthday?.date ?? Date(timeInterval: -3600, since: Date()) , telephone: contact.phoneNumbers.first?.value.stringValue ?? ""))
})
} else {
self.contacts = []
let predicate = CNContact.predicateForContacts(matchingName: self.searchText)
let contacts = try store.unifiedContacts(matching: predicate, keysToFetch: keysToFetch)
print(contacts)
for i in contacts{
self.contacts = [ContactsModel(firstName: i.givenName, lastName: i.familyName, telephone: i.phoneNumbers.first?.value.stringValue ?? "")]
// self.contacts.append(ContactsModel(firstName: i.givenName, lastName: i.familyName, telephone: i.phoneNumbers.first?.value.stringValue ?? ""))
}
}
} catch let error {
print("Failed to enumerate contact", error)
}
} else {
print("access denied")
}
}
}
}

Answer 1

Try with searchText as a #Published var. Then use Combine to subscribe to, adding a debounce. In this way, you can limit the frequency of execution of the fetch request.
It would be something like this
$searchText
.debounce(for: 5, scheduler: RunLoop.main) //5 seconds debounce
.sink(
receiveValue: {
self.fetchContacts()
}
)
.store(in: &disposables)