UIKit Debounced Search Example (AsyncStream vs Combine)

This project demonstrates how to implement debounced text search in a UITextField using two different approaches in UIKit:

• Swift Concurrency with AsyncStream
• Reactive programming with Combine

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Features

• Realtime search triggered by typing in a text field
• Debounced input: waits 0.5 seconds after typing stops before triggering a search
• Filters results from a mock local data source
• Displays matched results in a UILabel

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Technologies

Technique	Key APIs Used
AsyncStream	AsyncStream, Task.sleep, debounce helper
Combine	PassthroughSubject, .debounce, .flatMap, Just

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AsyncStream Version

• Uses AsyncStream<String> to stream user input.
• Adds a debounced(for:) extension to delay emission.
• Simple and clean async/await syntax without external dependencies.

Pros:

• Readable and modern with Swift Concurrency
• Ideal for one-to-one consumption flows
• Minimal overhead, fully native

Cons:

• Requires custom debounce implementation
• No native support for complex operators (e.g. combineLatest)

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Combine Version

• Uses PassthroughSubject to capture UITextField input.
• Applies .removeDuplicates() and .debounce() operators.
• Uses .flatMap to perform asynchronous search simulation.

Pros:

• Powerful reactive operators built-in
• Better suited for complex event stream composition
• Mature and extensible for multi-subscriber use

Cons:

• Slightly more complex code
• Requires understanding of reactive flow

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Example Search Terms

Try typing:

• "Mac" → matches MacBook, Mac Mini, etc.
• "i" → matches iMac, iPhone, iPad
• Typing quickly will debounce intermediate inputs

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Requirements

• iOS 15+
• Swift 5.7+
• Xcode 14+