struct MyComponent: View {
var displayString: String
var body: some View {
Text(displayString)
}
}














Compare Declarative Frameworks





@Composable
fun MyComponent(
displayString: String
) {
Text(displayString)
}
function MyComponent(props) {
return <div>{props.displayString}</div>;
}
struct ConditionalComponent: View {
let condition: Bool
var body: some View {
Group {
if condition {
Text("Condition is true")
} else {
Text("Condition is false")
}
}
}
}
// Usage
ConditionalComponent(condition: true)
@Composable
fun ConditionalComponent(condition: Boolean) {
if (condition) {
Text("Condition is true")
} else {
Text("Condition is false")
}
}
// Usage
ConditionalComponent(condition = true)
function ConditionalComponent({ condition }) {
return (
<>
{condition ? (
<p>Condition is true</p>
) : (
<p>Condition is false</p>
)}
</>
);
}
// Usage
<ConditionalComponent condition={true} />;
struct Parent: View {
let data: String
var body: some View {
IntermediateComponent(data: data)
}
}
struct IntermediateComponent: View {
let data: String
var body: some View {
ChildComponent(data: data)
}
}
struct ChildComponent: View {
let data: String
var body: some View {
Text("Received data: \(data)")
}
}
// Usage
Parent(data: "Some data")
@Composable
fun Parent(data: String) {
IntermediateComponent(data = data)
}
@Composable
fun IntermediateComponent(data: String) {
ChildComponent(data = data)
}
@Composable
fun ChildComponent(data: String) {
Text("Received data: $data")
}
// Usage
Parent(data = "Some data")
function Parent({ data }) {
return <IntermediateComponent data={data} />;
}
function IntermediateComponent({ data }) {
return <ChildComponent data={data} />;
}
function ChildComponent({ data }) {
return <p>Received data: {data}</p>;
}
// Usage
<Parent data="Some data" />;
struct ClickableComponent: View {
@State private var clicked = false
var body: some View {
Button(action: {
clicked = true
}) {
Text(clicked ? "Button clicked" : "Click me")
}
}
}
@Composable
fun ClickableComponent() {
var clicked by remember { mutableStateOf(false) }
Button(onClick = { clicked = true }) {
Text(if (clicked) "Button clicked" else "Click me")
}
}
import { useState } from "react";
function ClickableComponent() {
const [clicked, setClicked] = useState(false);
return (
<button onClick={() => setClicked(true)}>
{clicked ? "Button clicked" : "Click me"}
</button>
);
}
struct TextInputComponent: View {
@State private var text = ""
var body: some View {
TextField("Enter text", text: $text)
}
}
@Composable
fun TextInputComponent() {
var text by remember { mutableStateOf("") }
TextField(
value = text,
onValueChange = { newText -> text = newText },
label = { Text("Enter text") }
)
}
function TextInputComponent() {
const [text, setText] = useState("");
return (
<input
type="text"
value={text}
onChange={(e) => setText(e.target.value)}
placeholder="Enter text"
/>
);
}
struct ExampleComponent: View {
var body: some View {
Text("Hello, World!")
}
}
struct ExampleComponent_Previews: PreviewProvider {
static var previews: some View {
ExampleComponent()
}
}
@Composable
fun ExampleComponent() {
Text("Hello, World!")
}
@Preview(showBackground = true)
@Composable
fun ExampleComponentPreview() {
ExampleComponent()
}
Additionally, you can also use Showkase, an open source library by Airbnb that allows you to view themes preview functions in an auto-generated component browser that can be viewed on an Android device.
React doesn't have a built-in preview feature. However, you can use a tool like Storybook to create previews for your components in a separate development environment.
struct ListComponent: View {
let items: [String]
var body: some View {
List(items, id: \.self) { item in
Text(item)
}
}
}
// Usage
let items = ["Item 1", "Item 2", "Item 3"]
ListComponent(items: items)
@Composable
fun ListComponent(items: List<String>) {
LazyColumn {
items(items) { item ->
Text(item)
}
}
}
// Usage
val items = listOf("Item 1", "Item 2", "Item 3")
ListComponent(items = items)
function ListComponent({ items }) {
return (
<ul>
{items.map((item) => (
<li key={item}>{item}</li>
))}
</ul>
);
}
// Usage
const items = ["Item 1", "Item 2", "Item 3"];
<ListComponent items={items} />;
struct Person: Identifiable {
let name: String
let age: Int
let id: String
}
struct ItemKeysExample: View {
let items: [Person]
var body: some View {
List(items) { person in
Text("Name: \(person.name), Age: \(person.age)")
}
}
}
// Usage
ItemKeysExample(items: [Person(name: "John", age: 30, id: "1"), Person(name: "Jane", age: 28, id: "2"), Person(name: "Bob", age: 25, id: "3")])
data class Person(val name: String, val age: Int, val id: String)
@Composable
fun ItemKeysExample(items: List<Person>) {
LazyColumn {
items(items, key = { person -> person.id }) { person ->
Text("Name: ${person.name}, Age: ${person.age}")
}
}
}
function ItemKeysExample({ items }) {
return (
<ul>
{items.map((person) => (
<li key={person.id}>
Name: {person.name}, Age: {person.age}
</li>
))}
</ul>
);
}
// Usage
<ItemKeysExample
items={[
{ name: "John", age: 30, id: "1" },
{ name: "Jane", age: 28, id: "2" },
{ name: "Bob", age: 25, id: "3" },
]}
/>;
struct Parent<Header: View, Content: View>: View {
let header: Header
let content: Content
var body: some View {
VStack {
header
content
}
}
}
// Usage
Parent(
header: Text("Header"),
content: Child()
)
struct Child: View {
var body: some View {
Text("Child Content")
}
}
@Composable
fun Parent(
header: @Composable () -> Unit,
content: @Composable () -> Unit
) {
Column {
header()
content()
}
}
// Usage
Parent(
header = { Text("Header") },
content = { Child() }
)
@Composable
fun Child() {
Text("Child Content")
}
function Parent({ header, content }) {
return (
<div>
{header}
{content}
</div>
);
}
// Usage
<Parent header={<h1>Header</h1>} content={<Child />} />;
function Child() {
return <p>Child Content</p>;
}
struct ModifiersExample: View {
var body: some View {
Text("Hello, World!")
.padding(EdgeInsets(top: 16, leading: 16, bottom: 16, trailing: 16))
.background(Color.blue)
}
}
@Composable
fun ModifiersExample() {
Text(
"Hello, World!",
modifier = Modifier
.padding(16.dp)
.background(Color.Blue)
)
}
React doesn't have a direct analog to modifiers in Jetpack Compose or SwiftUI. Instead, you can use inline styles or CSS classes.
function ModifiersExample() {
const style = {
padding: "16px",
backgroundColor: "blue",
color: "white",
};
return <div style={style}>Hello, World!</div>;
}
struct Counter: View {
@State private var count = 0
var body: some View {
Button(action: {
count += 1
}) {
Text("Count: \(count)")
}
}
}
@Composable
fun Counter() {
var count by remember { mutableStateOf(0) }
Button(onClick = { count = count + 1 }) {
Text("Count: $count")
}
}
import { useState } from "react";
function Counter() {
const [count, setCount] = useState(0);
return (
<button onClick={() => setCount(count + 1)}>
Count: {count}
</button>
);
}
struct CustomEnvironmentKey: EnvironmentKey {
static let defaultValue: String = ""
}
extension EnvironmentValues {
var customData: String {
get { self[CustomEnvironmentKey.self] }
set { self[CustomEnvironmentKey.self] = newValue }
}
}
struct Parent: View {
let data: String
var body: some View {
Intermediate().environment(\.customData, data)
}
}
struct Intermediate: View {
var body: some View {
Child()
}
}
struct Child: View {
@Environment(\.customData) private var data
var body: some View {
Text("Received data: \(data)")
}
}
// Usage
Parent(data: "Some data")
val CustomLocal = compositionLocalOf<String> { "Default data" }
@Composable
fun Parent(data: String) {
CompositionLocalProvider(CustomLocal provides data) {
Intermediate()
}
}
@Composable
fun Intermediate() {
Child()
}
@Composable
fun Child() {
val data = CustomLocal.current
Text("Received data: $data")
}
// Usage
Parent(data = "Some data")
import { createContext, useContext } from "react";
const CustomContext = createContext();
function Parent({ data }) {
return (
<CustomContext.Provider value={data}>
<Intermediate />
</CustomContext.Provider>
);
}
function Intermediate() {
return <Child />;
}
function Child() {
const data = useContext(CustomContext);
return <p>Received data: {data}</p>;
}
// Usage
<Parent data="Some data" />;
struct SideEffectOnLoadComponent: View {
@State private var hasPerformedSideEffect = false
var body: some View {
if !hasPerformedSideEffect {
DispatchQueue.main.async {
// Perform side effect, e.g. fetch data, update external data source
hasPerformedSideEffect = true
}
}
// Other UI components
Text("Hello, World!")
}
}
@Composable
fun SideEffectOnLoadComponent() {
LaunchedEffect(Unit) {
// Perform side effect, e.g. fetch data, update external data source
}
// Other UI components
Text("Hello, World!")
}
import { useEffect } from "react";
function SideEffectOnLoadComponent() {
useEffect(() => {
// Perform side effect, e.g. fetch data, update external data source
}, []);
// Other UI components
return <div />;
}
Frequently Asked Questions About SwiftUI vs Jetpack Compose vs React
Which is better for beginners, SwiftUI or Jetpack Compose or React?
Let's analyze the learning curve and requirements for each framework in 2025:
SwiftUI (4/5)
SwiftUI offers an intuitive approach for iOS development with excellent documentation and powerful preview features. While it requires understanding Swift and iOS concepts, its declarative syntax and strong type system help catch errors early and make the development process more predictable.
Learning Path:
- Master Swift basics (especially protocols and property wrappers)
- Understand iOS app architecture
- Learn SwiftUI view hierarchy and data flow
- Practice with property wrappers and state management
- Explore SwiftUI's animation system
Key Prerequisites:
- Swift
- iOS development concepts
- Xcode
Time to Productivity: 2-3 months for iOS developers, 4-5 months for beginners
React (4/5)
React's component-based architecture and extensive ecosystem make it accessible for beginners. While concepts like hooks and virtual DOM require time to master, the large community and abundance of learning resources help overcome challenges. TypeScript adoption adds type safety but increases the initial learning curve.
Learning Path:
- Learn modern JavaScript/TypeScript
- Understand React components and JSX
- Master hooks and state management
- Learn component lifecycle and effects
- Practice React patterns and best practices
Key Prerequisites:
- JavaScript/TypeScript
- HTML/CSS
- npm/yarn
Time to Productivity: 2-3 months for web developers, 3-4 months for beginners
Jetpack Compose (3/5)
Jetpack Compose has a moderate learning curve that requires understanding of Kotlin and Android fundamentals. Its functional programming approach and declarative syntax can be challenging for developers coming from imperative XML layouts, but the excellent tooling and preview system make the learning process smoother.
Learning Path:
- Learn Kotlin fundamentals (especially lambdas and higher-order functions)
- Understand Android Activity/Fragment lifecycle
- Master Compose basics (composables, state, side effects)
- Learn Material Design components and theming
- Practice state management and composition patterns
Key Prerequisites:
- Kotlin
- Android basics
- Gradle build system
Time to Productivity: 2-3 months for Android developers, 4-6 months for beginners
Recommendation
Based on the analysis, SwiftUI offers the most approachable learning curve. However, your choice should depend on:
- Your existing programming background (Swift, Kotlin, JavaScript/TypeScript)
- Target platform requirements (iOS, Android, Cross-platform)
- Available learning time (2-3 months for iOS developers, 4-5 months for beginners for SwiftUI)
- Long-term career goals in mobile/web development
How does the performance of SwiftUI compare to Jetpack Compose in real-world applications?
Let's analyze the real-world performance characteristics of SwiftUI and Jetpack Compose based on benchmarks and practical experience:
SwiftUI Performance Profile
Strengths
-
✓ Efficient diffing algorithm
Uses a sophisticated diffing algorithm to minimize view updates and maintain smooth performance.
-
✓ Native platform optimization
Direct integration with Apple's rendering engine provides excellent performance on iOS devices.
-
✓ Automatic memory management
Swift's ARC (Automatic Reference Counting) ensures efficient memory usage.
Areas for Optimization
-
! List performance issues
Complex lists with dynamic content can experience performance degradation.
-
! State propagation overhead
Deep view hierarchies with frequent state updates can impact performance.
Jetpack Compose Performance Profile
Strengths
-
✓ Efficient recomposition system
Uses smart recomposition that only updates components when their inputs change, reducing unnecessary UI updates.
-
✓ Optimized rendering pipeline
Compose leverages Android's rendering pipeline to optimize performance for animations and transitions.
-
✓ Memory efficiency
Compose's compiler plugin optimizes memory allocation by reusing existing objects and reducing unnecessary allocations during UI updates.
Areas for Optimization
-
! Initial release overhead
First-time compilation and initial app startup time can be slower compared to XML layouts. You can address this by leveraging Baseline Profile.
-
! Complex state management impact
Improper state management can trigger unnecessary recompositions, affecting performance.
Performance Optimization Tips
SwiftUI
- Use @StateObject for expensive objects that need to persist
- Implement lazy loading with LazyVStack and LazyHStack
- Leverage SwiftUI's built-in performance tools
- Profile with Instruments to identify bottlenecks
Jetpack Compose
- Use remember() and derivedStateOf() to minimize recompositions
- Implement proper key() usage in lists for efficient updates
- Leverage Compose's built-in lazy loading components
- Profile with Android Studio's Layout Inspector and Performance tools
What are the key architectural differences between SwiftUI and Jetpack Compose and React?
Here are the key differences between SwiftUI and Jetpack Compose and React:
Feature | SwiftUI | Jetpack Compose | React |
---|---|---|---|
Paradigm | Declarative UI framework with a protocol-oriented approach | Declarative UI toolkit with a functional programming approach | Declarative UI library with a component-based approach |
Target Platform | Apple platforms (iOS, macOS, watchOS, tvOS) | Android (with experimental desktop support) | Web (with React Native for mobile) |
Language | Swift | Kotlin | JavaScript/TypeScript |
Component Model | View protocol conforming structs | Composable functions | Function components with hooks or class components |
State Management | Property wrappers (@State, @Binding, @ObservedObject) | State hoisting with remember and mutableStateOf | useState, useReducer, and third-party solutions like Redux |
Ecosystem | Tightly integrated with Apple's development ecosystem | Integrated with Android ecosystem and Kotlin coroutines | Vast ecosystem with many libraries and tools |
The choice between these frameworks often depends on your target platform, existing expertise, and specific project requirements. SwiftUI and Jetpack Compose and React each have their strengths in different contexts.
What are the job market trends for SwiftUI vs Jetpack Compose vs React in 2025?
If you're considering a career move in 2025, here's how these frameworks compare in terms of job prospects:
SwiftUI
- Current Demand: Increasing as iOS apps adopt the newer framework
- Growth Trajectory: Steady growth as Apple continues to enhance capabilities
- Notable Companies: Apple, Uber, Lyft, Airbnb
Jetpack Compose
- Current Demand: Growing rapidly as more Android apps transition from XML layouts
- Growth Trajectory: Strong upward trend as Google pushes it as the future of Android UI
- Notable Companies: Google, Twitter, Square, Airbnb
React
- Current Demand: Very high demand across web, mobile (React Native), and desktop
- Growth Trajectory: Mature but still growing with continuous innovation
- Notable Companies: Meta, Netflix, Airbnb, Dropbox
For mobile development, specializing in both Jetpack Compose and SwiftUI makes you versatile across the two major mobile platforms, though each individually pairs well with their platform-specific knowledge.
Can SwiftUI and Jetpack Compose and React be used together in the same project?
Understanding how SwiftUI and Jetpack Compose and React can work together:
SwiftUI + Jetpack Compose
SwiftUI and Jetpack Compose cannot be directly integrated as they target different platforms (iOS vs. Android). However, you can share business logic between them using Kotlin Multiplatform.
SwiftUI + React
React (via React Native) can use SwiftUI through native modules, though this is complex and not typically recommended.
Jetpack Compose + React
React (via React Native) can use Jetpack Compose through native modules, though this is complex. Alternatively, Compose for Web is an experimental project that brings Compose concepts to web development.
Using multiple frameworks: While it's technically possible to use SwiftUI, Jetpack Compose, React in a single project ecosystem, this adds complexity. It's generally better to choose the right tool for each platform and maintain consistency within that platform.
Web + Mobile Strategy: A common approach is to use React for your web application, while using SwiftUI or Jetpack Compose for mobile apps. You can share business logic and API calls between them, but the UI layer would be implemented separately for each platform.
Can I share code between Jetpack Compose and SwiftUI?
Yes, you can share code between Jetpack Compose and SwiftUI applications using Kotlin Multiplatform (KMP). Here's how:
- Shared Business Logic: Use KMP to write your data models, repositories, and business logic once in Kotlin and use it on both platforms.
- Platform-Specific UI: Write your UI separately with Jetpack Compose for Android and SwiftUI for iOS, but have them connect to the shared KMP code.
- Networking & Storage: Libraries like Ktor (networking) and SQLDelight (database) work well with KMP to share these layers across platforms.
How does Jetpack Compose compare to traditional Android XML layouts?
Jetpack Compose represents a significant shift from traditional Android XML layouts:
Traditional XML Layouts
- Declarative XML with imperative Java/Kotlin manipulation
- View hierarchy with expensive findViewById() calls
- Complex layouts like ConstraintLayout for performance
- Separate files for layouts, styles, and logic
- Many boilerplate adapters and view holders
- Slow layout inflation process
Jetpack Compose
- Fully declarative Kotlin code for UI
- No view hierarchy or findViewById()
- Layout composables handle optimization automatically
- UI, styling, and logic in one place
- Simple list creation with LazyColumn/LazyRow
- No layout inflation, faster rendering
Compose brings significant advantages in:
- Code reduction: Much less boilerplate code compared to XML
- State management: Built-in state handling with react-like patterns
- Preview: @Preview annotation for seeing UI changes without deploying
- Animation: Simplified animations with type-safe builders
- Testing: Better testability without complex UI testing setups
Migration can be gradual - Compose can be adopted incrementally within existing XML-based apps through the ComposeView component.