Update JSPromise publisher for JSKit 0.10 (#4)

* Update `JSPromise` implementation for JSKit 0.10

* Update JavaScriptKit requirement in Package.swift

* Update `README.md`

Author: MaxDesiatov

Package.resolved

@@ -10,7 +10,7 @@ let package = Package(
     .package(
       name: "JavaScriptKit",
       url: "https://github.com/swiftwasm/JavaScriptKit.git",
-      from: "0.9.0"
+      from: "0.10.0"
     ),
     .package(url: "https://github.com/TokamakUI/OpenCombine.git", from: "0.12.0-alpha3"),
   ],

Package.swift

@@ -28,7 +28,7 @@ import OpenCombine
 import OpenCombineJS
 
 private let jsFetch = JSObject.global.fetch.function!
-func fetch(_ url: String) -> JSPromise<JSObject, JSError> {
+func fetch(_ url: String) -> JSPromise {
   JSPromise(jsFetch(url).object!)!
 }
 
@@ -42,7 +42,7 @@ let timer = JSTimer(millisecondsDelay: 1000, isRepeating: true) {
   subscription = fetch("https://httpbin.org/uuid")
     .publisher
     .flatMap {
-      JSPromise<JSValue, JSError>($0.json!().object!)!.publisher
+      JSPromise($0.json().object!)!.publisher
     }
     .mapError { $0 as Error }
     .map { Result<String, Error>.success($0.uuid.string!) }

README.md

@@ -15,46 +15,36 @@
 import JavaScriptKit
 import OpenCombine
 
-public extension JSPromise where Success: ConstructibleFromJSValue, Failure: JSError {
+public extension JSPromise {
   final class PromisePublisher: Publisher {
-    public typealias Output = Success
-
-    /// Reference to a parent promise instance to prevent early deallocation
-    private var parent: JSPromise?
-
-    /// Reference to a `then` success callback promise instance to prevent early deallocation
-    private var then: JSPromise<JSValue, Failure>?
+    public typealias Output = JSValue
+    public typealias Failure = JSValue
 
     /// `Future` instance that handles subscriptions to this publisher.
-    private var future: Future<Success, Failure>?
-
-    fileprivate init(parent: JSPromise) {
-      future = .init { [weak self] resolver in
-        let then = parent.then { value -> JSValue in
-          resolver(.success(value))
-          return .undefined
-        }
-
-        then.catch {
+    private var future: Future<JSValue, JSValue>
+
+    fileprivate init(promise: JSPromise) {
+      future = .init { resolver in
+        promise.then(success: {
+          resolver(.success($0))
+          return JSValue.undefined
+        }, failure: {
           resolver(.failure($0))
-        }
-        self?.then = then
+          return JSValue.undefined
+        })
       }
-      self.parent = parent
     }
 
     public func receive<Downstream: Subscriber>(subscriber: Downstream)
-      where Success == Downstream.Input, Failure == Downstream.Failure
+      where Downstream.Input == JSValue, Downstream.Failure == JSValue
     {
-      guard let parent = parent, let then = then, let future = future else { return }
-
-      future.receive(subscriber: WrappingSubscriber(inner: subscriber, parent: parent, then: then))
+      future.receive(subscriber: WrappingSubscriber(inner: subscriber))
     }
   }
 
   /// Creates a new publisher for this `JSPromise` instance.
   var publisher: PromisePublisher {
-    .init(parent: self)
+    .init(promise: self)
   }
 
   /** Helper type that wraps a given `inner` subscriber and holds references to both stored promises
@@ -66,8 +56,6 @@ public extension JSPromise where Success: ConstructibleFromJSValue, Failure: JSE
     typealias Failure = Inner.Failure
 
     let inner: Inner
-    let parent: JSPromise
-    let then: JSPromise<JSValue, Failure>
 
     var combineIdentifier: CombineIdentifier { inner.combineIdentifier }
 

Sources/OpenCombineJS/JSPromise.swift

@@ -3,7 +3,7 @@ import OpenCombine
 import OpenCombineJS
 
 private let jsFetch = JSObject.global.fetch.function!
-func fetch(_ url: String) -> JSPromise<JSObject, JSError> {
+func fetch(_ url: String) -> JSPromise {
   JSPromise(jsFetch(url).object!)!
 }
 
@@ -17,7 +17,7 @@ let timer = JSTimer(millisecondsDelay: 1000, isRepeating: true) {
   subscription = fetch("https://httpbin.org/uuid")
     .publisher
     .flatMap {
-      JSPromise<JSValue, JSError>($0.json!().object!)!.publisher
+      JSPromise($0.json().object!)!.publisher
     }
     .mapError { $0 as Error }
     .map { Result<String, Error>.success($0.uuid.string!) }