Stop using MVVM for SwiftUI

@Luccif

One of the solution is to put domain logic right inside the SwiftData model. This is shown below:

@Model class BudgetCategory {

@Attribute(.unique) var title: String = ""
var amount: Decimal = 0.0
@Relationship(deleteRule: .cascade) var transactions: [Transaction] = []

init(title: String, amount: Decimal) {
    self.title = title
    self.amount = amount
}

// exists function to check if title already exist or not
private func exists(context: ModelContext, title: String) -> Bool {
    
    let predicate = #Predicate<BudgetCategory> { $0.title == title }
    let descriptor = FetchDescriptor(predicate: predicate)
    
    do {
        let result = try context.fetch(descriptor)
        return !result.isEmpty ? true: false
    } catch {
        return false
    }
}

func save(context: ModelContext) throws {
    
    // find if the budget category with the same name already exists
    if !exists(context: context, title: self.title) {
        // save it
        context.insert(self)
    } else {
        // do something else
        throw BudgetCategoryError.titleAlreadyExist
    }
}

}

Source: https://azamsharp.com/2023/07/04/the-ultimate-swift-data-guide.html

You can also watch my video on SwiftData Testing Domain Models. https://www.youtube.com/watch?v=OF7TLbMu1ZQ&t=389s

I stared working on an open source project called "HelloMarket". It is an E-Commerce application using SwiftUI, ExpressJS and Postgres database. Currently, it is in development phase but you can explore the repository.

https://github.com/azamsharpschool/HelloMarket