Questions tagged [swift-language]
Swift is a programming language designed by Apple for creating iOS and OS X apps. Swift builds upon the foundation of C and Objective-C.
111 questions
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Swift: What is the rationale behind forbidding named parameters for closures?
In Swift, functions can be defined with named parameters, for example:
func greet(person: String) -> String {
...
}
which need to be used when the function is called :
greet(person: "Anna&...
- 286
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vote
1
answer
253
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SPM: Expose transitive dependency types
I'm developing a Swift Package distributed via Swift Package Manager (SPM). I have other dependencies (Swift packages) that my package depends on. Is it possible to expose types (classes, structs, etc....
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3
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1
answer
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Unit Test Against In-Memory vs Real Database for SwiftData Applications
I am writing unit tests for my SwiftData application. Currently, I am using in-memory database, which get reset after every test. What benefits will I gain if I start using real database? My main ...
- 139
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How do I mock API responses with security in mind?
My team and I are beginning to mock our API responses in our iOS app so we don't have to worry about our backend being up when testing.
I have conditional compilation directives based on the ...
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answers
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When should tuples be used as an argument instead of an array?
I hope this isn't too off-topic/opinion-based, I'm new here.
I want to pass three elements of the same type into a function. The three elements are unique cards of a deck of cards, so they're not ...
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Design for the future or make it tightly coupled to the implementation
My question is regarding how would the developer know when you add interfaces/protocols to their code and inject them as dependency.
Consider an example of BudgetService.
protocol ...
- 141
3
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1
answer
191
views
Should I have different instances of the same model in an application or just keep a single instance?
What is correct in your opinion regarding the creation and handling of models in an application let's say using MVVM, or even an MVC design pattern?
I will try to illustrate the situation I see at my ...
- 139
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2k
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Is it okay for an Interface Adapter / Repository / Gateway to use Entities in its implementation
I've got these classes:
enum Environment {
case staging
case production
static func current() -> Environment {
#if STAGING
return .staging
#elseif PROD
...
1
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1
answer
408
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SwiftUI View permissions best practice?
I am currently developing an iOS application where there are options on the screen to edit and delete a list. Only the user who created this list can edit or delete it. I am struggling to determine ...
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1
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Store/Pass User data MVVM+C swift
I have an app written using MVVM and RxSwift.
For navigation I'm using coordinator
What is the best way to store user's credentials and pass them to Network Layer.
I don't want to sore them in DB or ...
- 107
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4
answers
321
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Swift: Best way to store crypto amounts?
Having a bit of trouble on deciding the best way to store crypto values which are usually in decimals. Do I go with Double or Float? Or is there an even better type that Swift offers?
My initial gut ...
- 139
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167
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Guidelines for using extensions in Swift
The other day, I came across this question on StackOverflow. In short, the user who asked the question wanted to extend a class from a third-party library to implement the Codable protocol, but ...
- 152
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1
answer
10k
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The right place for "app logic" in MVVM context
I hope this is the right place to ask.
I'm an experienced developer, and have used MVC for much time.
This question is in the context of iOS/macOS development for the most part, (SwiftUI).
Using MVC ...
- 201
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0
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44
views
Should I separate a variable that changes often into a different entity although it is contextually should be inside another entity?
So, I have an entity called Consultation that is being used as a member variable of the class VideoCallViewModel that goes like this:
struct Consultation: Equatable {
enum Status: Int, ...
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0
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1k
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Best practices for viewmodels for SwiftUI preview?
Are there best practices about how to prepare lightweight viewmodels with dummy data, that could be used in SwiftUI previews?
Right now, I have a viewmodel for an in-app purchase screen, that needs to ...
- 141
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231
views
What would be a good approach to applying computer vision to automatically edit out the downtime in tennis video?
I have an iOS/macOS tennis app that now lets the user import video, and I would like to add the ability to automatically edit out the significant amount of downtime where players are not in a rally or ...
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What is a good naming convention for Interface Adapters, Use Cases / Interactors, Entities?
I'm using MVVM + Clean Architecture in my app. And I sometimes don't have any idea if my namings are good enough for each Interface Adapters, Use Cases / Interactors, Entities. For View Models, it's ...
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2
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713
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Clean Code: How much architecture code should be written if architecture is supposed to be fluid
I watched a video series from Uncle Bob on Clean Code. He makes a few points on architecture which I both agree with but I believe could have clarification.
From Uncle Bob:
The Interactor is ...
1
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1
answer
133
views
What is better way to track mistakes in error-prone part of a feature?
That is quite specific circumstances I've come across, and I somewhat struggle to find proper way how to approach this.
I'm given a class written in swift-language, which has a control property, like ...
-2
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1
answer
344
views
Best way to deal with lots of nested closures in Swift
I have some external SDK library that makes IO calls (either networking or database) in the form of blocks, like so:
SomeClass.doWork(success: {}, failure: {})
Now I need to chain about 60 different ...
- 384
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0
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67
views
What is the idiomatic Swift way to add general functionality via protocol/extension?
I am a scala developer new to swift. In scala we can share implementation across a variety of classes by "extending" a trait that has default implementations for the methods. I would like to see how ...
1
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0
answers
385
views
Common patterns for Observable data layer on iOS
I am working on learning native iOS development in Swift, and I am trying to find something that is similar to what I've learned in Android development with Kotlin.
In particular I am referring to ...
- 171
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1
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Need technical advice about passing data through UINavigationController
First of all a small introduction, im relatively new to Swift and to programming in general, been doing it for the last year and loving every and each new thing of this vast world.
My post is about ...
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3
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337
views
How to Replace Many if Statements for many types
I have many dependent statements. What is the best approach to handle these cases dynamically?
Example
enum UserType {
case buyer
case seller
}
enum ViewType {
case active
case ...
- 101
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5
answers
548
views
What is a good approach to naming when modeling a sport that can be between either individuals or teams?
Tennis is played as singles or doubles. I considered making my tennis scoring model logic refer to "teams" throughout its naming since "player" wouldn't take into account doubles. However, seeing ...
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1
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258
views
Building native iOS app that runs on iPhone, iPad and Mac
Since Apple introduced Catalyst ealier this year during WWDC '19 it becomes possible to have a single codebase for an app that runs on iPads and Macs.
Already for a long time it was possible to ...
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4
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338
views
Should a transformation function take a nullable and return a nullable or should the caller handle nullability
Often I need to transform a type to another, such as a networking model to a data model, or a data model to a binary representation. Should these transformation functions take an Optional/nullable ...
2
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2
answers
869
views
Localize a countdown timer
I have a very specific localization problem that I have not had any luck finding specific information about in my research.
I have an app that I'm localizing that shows elapsed minutes(M), seconds(S),...
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3
answers
8k
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Struggling with cyclical dependencies in unit tests
I'm trying to practice TDD, by using it to develop a simple like Bit Vector. I happen to be using Swift, but this is a language-agnostic question.
My BitVector is a struct that stores a single UInt64,...
- 5,195
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4k
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What is a good approach for saving a Swift model that's a struct containing structs to Core Data?
I'm new to Core Data, and am not sure how to reconcile the need to inherit from NSManagedObject with the fact that my model is a Swift struct composed of structs. I chose to make my a model value type ...
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2
answers
104
views
At what size array in Swift would you consider switching to CoreData?
I've developed a reading tracking app in Swift and for simplicity's sake I used arrays for my model. It stores some data about the books a user reads and a small image of the cover. I save them to ...
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50
views
What is the advantage to inferred types *in Swift*? [duplicate]
As I fool around in Swift I have come to absolutely hate variable declarations. int c = 0 seems easier to read than var c:Int = 0 and more informative than var c = 0, and int some() is radically ...
- 111
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views
Modular Quiz in Swift
I've been working on the architecture of my Apps for a while.
In the past I've used a SQLite database which I opened in the AppDelegate (Oh dear), and then created a global variable (really!) to ...
- 111
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1
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59
views
Only be able to sign into app after existing user send invitation [closed]
I am looking to build an app where the only way a new user can enter the app is if they have been invited by an existing user. Are there any API's, tutorials or resources that can help me achieve this....
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2
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1k
views
Does chaining higher order functions mean worse performance?
For clarification, let's review the following example:
Consider that we have the following array of Ints:
let array = [1, 2, 3, 4, 5]
and we've been asked to generate a new array from array ...
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163
views
One-field interfaces
I have an interface with only one title field:
protocol Artist {
var title: String { get }
}
(A) Should I pass the whole object as I did here:
class Album {
func setArtist(_ artist: Artist) {...
- 103
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233
views
What design pattern would help me make my factory more generic
In my code I have 2 separate login types. I have a factory that decides which one to create based on an enum.
Each login type has a different type of credential.
Currently my factory method takes ...
- 109
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vote
2
answers
254
views
What is better approach to implement dependency injection using MVVM Architecture?
I need to use DispatchQueue within controller and pass it as dependency. This is what I have tried so far and worked out two solutions. Need to ask what is better and in common use by other developers:...
4
votes
1
answer
2k
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Repository that performs API calls internally - DDD
Please note: although my question relates to DDD, I am also interested in this from an architectural and OO design perspective. This question may also be a simple case of CQRS and/or interface ...
- 546
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vote
2
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322
views
Reusable component with web service
I am trying to create a reusable component / Cocoa Touch Framework in Swift that would display the current weather based on the user’s location.
Right now I cannot decide which approach should I take....
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votes
2
answers
399
views
Where to put private computed properties?
In Clean code it's suggested that private helper functions should always exist directly below the function they're directly used within. Should I be doing this when using computed properties? It's the ...
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1
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401
views
How to break down complex if conditions that include optional binding?
I've recently been reading Clean Code and there was a really nice example in java of when it is beneficial to break down a complex if statement condition in to a function rather than use a comment.
//...
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Is it good practice to wrap a related set of properties into its own struct/class?
Writing a User object in Swift, though my question relates to any strongly typed language. A User can have a bunch of links (FacebookProfile, InstagramProfile, etc). A few questions around this.
Is ...
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616
views
Dependency Inversion Principle (Swift) - Applicable also without polymorphism? (Abstraction: constrained generics)
There exist a number of articles/blogs explaining the Dependency Inversion Principle (DIP) using Swift; to name a few (top Google hits):
GitHub/ochococo/OOD-Principles-In-Swift - The Dependency ...
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1
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897
views
Does swift value type like String, Array, Dictionary internally contain class
I was watching WWDC video and can not understand when they talk about
Even though all of these properties are value types, internally, they
contain a class which is used to manage the lifetime of ...
- 141
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1
answer
4k
views
Why doesn't Swift allow Int String subscripting and integer ranges directly?
If I have a string:
let str = "Hello world"
It seems quite reasonable to be able to extract a character:
let thirdChar = str[3]
However, that's not legal. Instead, I have to use the extremely obtuse ...
- 197
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vote
3
answers
224
views
Should I write out computed vars that all depend on one other var, or should I assign them as normal vars in that single var's setter?
I'm using Swift, but I understand computed properties are a thing in a few other languages as well. I have the following case:
var bar in class Foo is changed throughout program flow.
vars a, b, c ...
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What is the best way using swift 4/iOS to handle asynchronous requests eg. to Firebase Database? [closed]
I've been using firebase database and now firestore for a while.
I'm prob an intermediate level programmer and still at uni.
I'm still a bit unsure re: the best way to handle calls that are occurring ...
- 141
3
votes
1
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621
views
Why doesn't Swift's Numeric protocol inherit from the Comparable protocol?
I created a generic class MyClass<T: Numeric> {...} and got errors in my functions that tried to use > and <, along the lines of "Binary operator '>' cannot be applied to two 'T' operands."...
- 139
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3
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Are nested closures a good thing?
I've been doing Swift development for a while now with Firebase, and I find myself making a lot of code like this:
Auth.auth().signIn(with: credential) { (user, error) in
if let error = error {
...
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