Dynamically filtering @query with SwiftUI + SwiftData

ContentView.swift

//
//  ContentView.swift
//  SwiftDataTest
//
//  Created by Matthew Edwards on 6/6/23.
//

import SwiftUI
import SwiftData

struct ContentView: View {
    @Environment(\.modelContext) private var modelContext
    @State private var lastNameFilter = ""
        
    var body: some View {
        VStack {
            FilteredList(filter: lastNameFilter)

            Button("Add Examples") {
                let singerArray: [Singer] = [
                    Singer(firstName: "Taylor", lastName: "Swift"),
                    Singer(firstName: "Ed", lastName: "Sheeran"),
                    Singer(firstName: "Adele", lastName: "Adkins")
                ]
                
                for singer in singerArray {
                    modelContext.insert(singer)
                }
            }

            Button("Show Adele") {
                lastNameFilter = "Adkins"
            }

            Button("Show Taylor") {
                lastNameFilter = "Swi"
            }
            
            Button("Show All") {
                lastNameFilter = ""
            }
        }
    }

    private func addSingers() {
        let singerArray: [Singer] = [
            Singer(firstName: "Taylor", lastName: "Swift"),
            Singer(firstName: "Ed", lastName: "Sheeran"),
            Singer(firstName: "Adele", lastName: "Adkins")
        ]
        
        for singer in singerArray {
            modelContext.insert(singer)
        }
    }
}

#Preview {
    ContentView()
        .modelContainer(for: Singer.self, inMemory: true)
}

FilteredList.swift

//
//  FilteredList.swift
//  SwiftDataTest
//
//  Created by Matthew Edwards on 6/6/23.
//

import SwiftUI
import SwiftData

struct FilteredList: View {
    @Environment(\.modelContext) private var modelContext
    @Query private var singers: [Singer]
    
    init(filter: String) {
        if filter.isEmpty {
            _singers = Query(filter: #Predicate<Singer> { $0.lastName.count > 0 },
                            sort: \.lastName,
                            order: .forward,
                            animation: .spring)
        } else {
            _singers = Query(filter: #Predicate<Singer> { $0.lastName.contains(filter) },
                             sort: \.lastName,
                             order: .forward,
                             animation: .spring)
        }
    }
    
    var body: some View {
        List {
            ForEach(singers, id: \.self) { singer in
                Text("\(singer.firstName) \(singer.lastName)")
            }
            .onDelete(perform: { indexSet in
                withAnimation {
                    for index in indexSet {
                        modelContext.delete(singers[index])
                    }
                }
            })
        }
    }
}

Singer.swift

//
//  Singer.swift
//  SwiftDataTest
//
//  Created by Matthew Edwards on 6/6/23.
//

import Foundation
import SwiftData

@Model
final class Singer {
    var firstName: String
    var lastName: String
    
    init(firstName: String, lastName: String) {
        self.firstName = firstName
        self.lastName = lastName
    }
}

Borrowed and adapted from Paul Hudson's excellent Hacking with Swift article: https://www.hackingwithswift.com/books/ios-swiftui/dynamically-filtering-fetchrequest-with-swiftui