Module API Reference

// Created from the dictionary
Constants([
  "PI": Double.pi
])

// or returned by the closure
Constants {
  return [
    "PI": Double.pi
  ]
}

// Passed as arguments
Constants(
  "PI" to kotlin.math.PI
)

// or returned by the closure
Constants {
  return@Constants mapOf(
    "PI" to kotlin.math.PI
  )
}

Function("syncFunction") { (message: String) in
  return message
}

Function("syncFunction") { message: String ->
  return@Function message
}

AsyncFunction("asyncFunction") { (message: String, promise: Promise) in
  DispatchQueue.main.asyncAfter(deadline: .now() + 3.0) {
    promise.resolve(message)
  }
}

AsyncFunction("asyncFunction") { message: String, promise: Promise ->
  launch(Dispatchers.Main) {
    promise.resolve(message)
  }
}

Events("onCameraReady", "onPictureSaved", "onBarCodeScanned")

Events("onCameraReady", "onPictureSaved", "onBarCodeScanned")

ViewManager {
  View {
    MyNativeView()
  }

  Prop("isHidden") { (view: UIView, hidden: Bool) in
    view.isHidden = hidden
  }
}

ViewManager {
  View { context ->
    MyNativeView(context)
  }

  Prop("isHidden") { view: View, hidden: Bool ->
    view.isVisible = !hidden
  }
}

View(UITextView.self) {
  Prop("text") { ... }
}

View(TextView::class) {
  Prop("text") { ... }
}

Prop("background") { (view: UIView, color: UIColor) in
  view.backgroundColor = color
}

Prop("background") { view: View, @ColorInt color: Int ->
  view.setBackgroundColor(color)
}

struct FileReadOptions: Record {
  @Field
  var encoding: String = "utf8"

  @Field
  var position: Int = 0

  @Field
  var length: Int?
}

// Now this record can be used as an argument of the functions or the view prop setters.
Function("readFile") { (path: String, options: FileReadOptions) -> String in
  // Read the file using given `options`
}

class FileReadOptions : Record {
  @Field
  val encoding: String = "utf8"

  @Field
  val position: Int = 0

  @Field
  val length: Int?
}

// Now this record can be used as an argument of the functions or the view prop setters.
Function("readFile") { path: String, options: FileReadOptions ->
  // Read the file using given `options`
}

enum FileEncoding: String, Enumerable {
  case utf8
  case base64
}

struct FileReadOptions: Record {
  @Field
  var encoding: FileEncoding = .utf8
  // ...
}

// Note: the constructor must have an argument called value.
enum class FileEncoding(val value: String) : Enumerable {
  utf8("utf8"),
  base64("base64")
}

class FileReadOptions : Record {
  @Field
  val encoding: FileEncoding = FileEncoding.utf8
  // ...
}

Function("foo") { (bar: Either<String, Int>) in
  if let bar: String = bar.get() {
    // `bar` is a String
  }
  if let bar: Int = bar.get() {
    // `bar` is an Int
  }
}

Function("foo") { bar: Either<String, Int> ->
  bar.get(String::class).let {
    // `it` is a String
  }
  bar.get(Int::class).let {
    // `it` is an Int
  }
}

class LinearGradientView: ExpoView {}

public class LinearGradientModule: Module {
  public func definition() -> ModuleDefinition {
    View(LinearGradientView.self) {
      // ...
    }
  }
}

class LinearGradientView(
  context: Context,
  appContext: AppContext,
) : ExpoView(context, appContext)

class LinearGradientModule : Module() {
  override fun definition() = ModuleDefinition {
    View(LinearGradientView::class) {
      // ...
    }
  }
}

let CLIPBOARD_CHANGED_EVENT_NAME = "onClipboardChanged"

public class ClipboardModule: Module {
  public func definition() -> ModuleDefinition {
    Events(CLIPBOARD_CHANGED_EVENT_NAME)

    OnStartObserving {
      NotificationCenter.default.addObserver(
        self,
        selector: #selector(self.clipboardChangedListener),
        name: UIPasteboard.changedNotification,
        object: nil
      )
    }

    OnStopObserving {
      NotificationCenter.default.removeObserver(
        self,
        name: UIPasteboard.changedNotification,
        object: nil
      )
    }
  }

  @objc
  private func clipboardChangedListener() {
    sendEvent(CLIPBOARD_CHANGED_EVENT_NAME, [
      "contentTypes": availableContentTypes()
    ])
  }
}

const val CLIPBOARD_CHANGED_EVENT_NAME = "onClipboardChanged"

class ClipboardModule : Module() {
  override fun definition() = ModuleDefinition {
    Events(CLIPBOARD_CHANGED_EVENT_NAME)

    OnStartObserving {
      clipboardManager?.addPrimaryClipChangedListener(listener)
    }

    OnStopObserving {
      clipboardManager?.removePrimaryClipChangedListener(listener)
    }
  }

  private val clipboardManager: ClipboardManager?
    get() = appContext.reactContext?.getSystemService(Context.CLIPBOARD_SERVICE) as? ClipboardManager

  private val listener = ClipboardManager.OnPrimaryClipChangedListener {
    clipboardManager?.primaryClipDescription?.let { clip ->
      this@ClipboardModule.sendEvent(
        CLIPBOARD_CHANGED_EVENT_NAME,
        bundleOf(
          "contentTypes" to availableContentTypes(clip)
        )
      )
    }
  }
}

class CameraViewModule: Module {
  public func definition() -> ModuleDefinition {
    View(CamerView.self) {
      Events(
        "onCameraReady"
      )

      // ...
    }
  }
}

class CameraView: ExpoView {
  let onCameraReady = EventDispatcher()

  func callOnCameraReady() {
    onCameraReady([
      "message": "Camera was mounted"
    ]);
  }
}

class CameraViewModule : Module() {
  override fun definition() = ModuleDefinition {
    View(ExpoCameraView::class) {
      Events(
        "onCameraReady"
      )

      // ...
    }
  }
}

class CameraView(
  context: Context,
  appContext: AppContext
) : ExpoView(context, appContext) {
  val onCameraReady by EventDispatcher()

  fun callOnCameraReady() {
    onCameraReady(mapOf(
      "message" to "Camera was mounted"
    ));
  }
}