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https://github.com/BrentMifsud/AsyncValue
A simple swift package that provides a Swift Concurrency equivalent to `@Published`.
https://github.com/BrentMifsud/AsyncValue
concurrency swift swift-concurrency
Last synced: about 2 months ago
JSON representation
A simple swift package that provides a Swift Concurrency equivalent to `@Published`.
- Host: GitHub
- URL: https://github.com/BrentMifsud/AsyncValue
- Owner: BrentMifsud
- License: mit
- Created: 2022-09-02T19:44:52.000Z (about 2 years ago)
- Default Branch: main
- Last Pushed: 2022-10-03T00:01:13.000Z (almost 2 years ago)
- Last Synced: 2024-07-14T05:42:43.374Z (2 months ago)
- Topics: concurrency, swift, swift-concurrency
- Language: Swift
- Homepage:
- Size: 28.3 KB
- Stars: 35
- Watchers: 3
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://swiftpackageindex.com/BrentMifsud/AsyncValue)
[](https://swiftpackageindex.com/BrentMifsud/AsyncValue)
[](https://github.com/BrentMifsud/AsyncValue/actions/workflows/Build.yml)
# AsyncValue
This is a simple package that provides a convenience property wrapper around AsyncStream that behaves almost identically to `@Published`.
# Installation
## Via Xcode
1. In the project navigator on the left, click on your project
2. click `Package Dependencies`
3. enter: [https://github.com/BrentMifsud/AsyncValue.git](https://github.com/BrentMifsud/AsyncValue.git) into the search bar
4. select the desired version and click `Add Package`
## Via Package.swift
in your `Package.swift` file, add the following:
```swift
let package = Package(
name: "MyPackage",
dependencies: [
.package(url: "https://github.com/BrentMifsud/AsyncValue.git", from: .init(1, 0, 0))
],
products: [
// Products define the executables and libraries a package produces, and make them visible to other packages.
.library(
name: "MyPackage",
targets: ["MyPackage"]
),
],
targets: [
// Targets are the basic building blocks of a package. A target can define a module or a test suite.
// Targets can depend on other targets in this package, and on products in packages this package depends on.
.target(
name: "MyPackage",
dependencies: ["AsyncValue"]
),
.testTarget(
name: "MyPackageTests",
dependencies: ["MyPackage"]
),
]
)
```
# Usage
## Accessing the current value
```swift
@AsyncValue var myValue: String = "Test"
print(myValue) // prints: test
```
## Observing changes to the value
Just like the publisher backing `@Published`, `AsyncValue` is backed by an AsyncStream. And you can subscribe to updates to the value.
```swift
@AsyncValue myValue: String = "Test"
Task {
for await value in myValue {
print("Value: \(value)")
}
}
Task {
await Task.sleep(nanoseconds: 1_000_000_000)
myValue = "New Value"
}
/* Prints:
Value: test
Value: New Value
*/
```
## Observing with multiple tasks
One of the major limitations of AsyncStream out of the box is that you can only `for-await-in` on it with a single task.
`AsyncValue` does not have this limitation:
```swift
@AsyncValue myValue: String = "Test"
Task {
for await value in myValue {
print("Task 1 Value: \(value)")
}
}
Task {
for await value in myValue {
print("Task 2 Value: \(value)")
}
}
Task {
await Task.sleep(nanoseconds: 1_000_000_000)
myValue = "New Value"
}
/* Prints (note that the order of the tasks printing may vary as this is happening asyncronously):
Task 1 Value: test
Task 2 Value: test
Task 2 Value: New Value
Task 1 Value: New Value
*/
```
## Using with SwiftUI
### ObservableObject support
`AsyncValue` can be adapted to work seamlessly with `ObservableObject` with a single line of code:
```swift
class MyObservableObject: ObservableObject {
@AsyncValue var myValue: String = "Test"
}
```
Any changes to an `AsyncValue` will trigger a view update in the same way `@Published` does.
Thanks to [jlsiewert](https://github.com/jlsiewert) for coming up with the cool trick for making this work automatically.
### .onReceive equivalent for `AsyncSequence`
There is also an `.onRecieve(sequence:perform:)` view modifier that allows you to respond to changes from any AsyncSequence.
```swift
struct MyView: View {
var body: some View {
Text("Hello World!")
.onReceive(myService.$myValue) { value in
print("The value changed to: \(value)")
}
}
}
class MyService: ObservableObject {
@AsyncValue var myValue: String = "Test"
}
```