refactor(ios): move rejectPromiseWithMessage helper into RNMLKit core (#260)

The rejectPromiseWithMessage Swift helper was duplicated verbatim in the
face-detection, object-detection, and image-labeling modules. Move it to
RNMLKitCore as a public function so it can be shared across modules
(including the upcoming barcode scanning module) instead of being copied
into each one.

Closes #254

Co-authored-by: Claude <noreply@anthropic.com>

Author: trevor-coleman

.changeset/move-reject-promise-to-core.md

@@ -0,0 +1,8 @@
+---
+"@infinitered/react-native-mlkit-core": minor
+"@infinitered/react-native-mlkit-face-detection": patch
+"@infinitered/react-native-mlkit-object-detection": patch
+"@infinitered/react-native-mlkit-image-labeling": patch
+---
+
+Move the `rejectPromiseWithMessage` Swift helper into RNMLKit core so it can be shared across modules instead of being duplicated in each one.

modules/react-native-mlkit-core/README.md

@@ -50,6 +50,23 @@ var image:InputImage = RNMLKitImage(imagePath, appContext.reactContext!!).image
   ImagePickerAsset.
 - `appContext` is the AppContext from your expo module -- it's accessible as a property on the Module class.
 
+### rejectPromiseWithMessage
+
+#### Swift
+
+A shared helper for rejecting an Expo `Promise` with a consistent `NSError` shape. Use it from any RNMLKit module to
+surface errors back to JavaScript.
+
+```swift
+import RNMLKitCore
+
+rejectPromiseWithMessage(promise: promise, message: "Something went wrong", domain: ERROR_DOMAIN)
+```
+
+- `promise` is the Expo `Promise` to reject.
+- `message` is the localized description attached to the error.
+- `domain` is the error domain (e.g. a module-specific error domain constant).
+
 ### React Components
 
 #### BoundingBoxView

modules/react-native-mlkit-core/ios/RNMLKitPromise.swift

@@ -0,0 +1,11 @@
+import ExpoModulesCore
+
+/// Rejects a promise with a specified message and domain.
+///
+/// Shared helper used across the React Native MLKit modules to surface
+/// errors back to JavaScript with a consistent `NSError` shape.
+public func rejectPromiseWithMessage(promise: Promise, message: String, domain: String) {
+    promise.reject(
+        NSError(domain: domain, code: 1, userInfo: [NSLocalizedDescriptionKey: message])
+    )
+}

modules/react-native-mlkit-face-detection/ios/RNMLKitFaceDetectionModule.swift

@@ -3,13 +3,6 @@ import ExpoModulesCore
 import MLKitFaceDetection
 import RNMLKitCore
 
-// Function to reject a promise with a specified message and domain
-func rejectPromiseWithMessage(promise: Promise, message: String, domain: String) {
-    promise.reject(
-        NSError(domain: domain, code: 1, userInfo: [NSLocalizedDescriptionKey: message])
-    )
-}
-
 let ERROR_DOMAIN: String = "red.infinite.reactnativemlkit.FaceDetectorErrorDomain"
 
 

modules/react-native-mlkit-image-labeling/ios/RNMLKitImageLabelingModule.swift

@@ -2,6 +2,7 @@ import ExpoModulesCore
 import MLKitCommon
 import MLKitImageLabelingCustom
 import MLKitVision
+import RNMLKitCore
 
 // Structure to represent the result of image labeling
 struct RNMLKitImageLabelResult: Record {
@@ -23,13 +24,6 @@ struct RNMLKitImageLabelerOptionsRecord: Record {
     var maxResultCount: Int = 10
 }
 
-// Function to reject a promise with a specified message and domain
-func rejectPromiseWithMessage(promise: Promise, message: String, domain: String) {
-    promise.reject(
-        NSError(domain: domain, code: 1, userInfo: [NSLocalizedDescriptionKey: message])
-    )
-}
-
 struct RNMLKitImageLabelerSpec: Record {
     @Field
     var modelName: String = ""

modules/react-native-mlkit-object-detection/ios/RNMLKitObjectDetectionModule.swift

@@ -1,11 +1,5 @@
 import ExpoModulesCore
-
-// Function to reject a promise with a specified message and domain
-func rejectPromiseWithMessage(promise: Promise, message: String, domain: String) {
-    promise.reject(
-        NSError(domain: domain, code: 1, userInfo: [NSLocalizedDescriptionKey: message])
-    )
-}
+import RNMLKitCore
 
 public struct RNMLKitObjectDetectionModelSpec: Record {
     public init() {}