Refine and operators in Swift

PromisesObjC.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name        = 'PromisesObjC'
-  s.version     = '1.0.2'
+  s.version     = '1.0.3'
   s.authors     = 'Google Inc.'
   s.license     = { :type => 'Apache', :file => 'LICENSE' }
   s.homepage    = 'https://github.com/google/promises'

PromisesSwift.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name        = 'PromisesSwift'
-  s.version     = '1.0.2'
+  s.version     = '1.0.3'
   s.authors     = 'Google Inc.'
   s.license     = { :type => 'Apache', :file => 'LICENSE' }
   s.homepage    = 'https://github.com/google/promises'

Sources/Promises/Promise+All.swift

@@ -41,12 +41,95 @@ public func all<Value, Container: Sequence>(
   on queue: DispatchQueue = .main,
   _ promises: Container
 ) -> Promise<[Value]> where Container.Iterator.Element == Promise<Value> {
+  let promises = promises.map { $0.objCPromise }
   let promise = Promise<[Value]>(
-    Promise<[Value]>.ObjCPromise<AnyObject>.__onQueue(queue, all: promises.map { $0.objCPromise })
+    Promise<[Value]>.ObjCPromise<AnyObject>.__onQueue(queue, all: promises)
   )
   // Keep Swift wrapper alive for chained promises until `ObjCPromise` counterpart is resolved.
   promises.forEach {
-    $0.objCPromise.__pendingObjects?.add(promise)
+    $0.__pendingObjects?.add(promise)
+  }
+  return promise
+}
+
+/// Waits until all of the promises have been fulfilled.
+/// If one of the promises is rejected, then the returned promise is rejected with same error.
+/// If any other arbitrary value or `Error` appears in the array instead of `Promise`,
+/// it's implicitly considered a pre-fulfilled or pre-rejected `Promise` correspondingly.
+/// - parameters:
+///   - queue: A queue to dispatch on.
+///   - promiseA: Promise of type `A`.
+///   - promiseB: Promise of type `B`.
+/// - returns: Promise of a tuple containing the values of input promises in the same order.
+public func all<A, B>(
+  on queue: DispatchQueue = .main,
+  _ promiseA: Promise<A>,
+  _ promiseB: Promise<B>
+) -> Promise<(A, B)> {
+  let promises = [
+    promiseA.objCPromise,
+    promiseB.objCPromise
+  ]
+  let promise = Promise<(A, B)>(
+    Promise<(A, B)>.ObjCPromise<AnyObject>.__onQueue(
+      queue,
+      all: promises
+    ).__onQueue(queue, then: { objCValues in
+      guard let values = objCValues as [AnyObject]?,
+            let valueA = Promise<A>.asValue(values[0]),
+            let valueB = Promise<B>.asValue(values[1])
+      else {
+        preconditionFailure("Cannot convert \(type(of: objCValues)) to \((A, B).self)")
+      }
+      return (valueA, valueB)
+    })
+  )
+  // Keep Swift wrapper alive for chained promises until `ObjCPromise` counterpart is resolved.
+  promises.forEach {
+    $0.__pendingObjects?.add(promise)
+  }
+  return promise
+}
+
+/// Waits until all of the promises have been fulfilled.
+/// If one of the promises is rejected, then the returned promise is rejected with same error.
+/// If any other arbitrary value or `Error` appears in the array instead of `Promise`,
+/// it's implicitly considered a pre-fulfilled or pre-rejected `Promise` correspondingly.
+/// - parameters:
+///   - queue: A queue to dispatch on.
+///   - promiseA: Promise of type `A`.
+///   - promiseB: Promise of type `B`.
+///   - promiseC: Promise of type `C`.
+/// - returns: Promise of a tuple containing the values of input promises in the same order.
+public func all<A, B, C>(
+  on queue: DispatchQueue = .main,
+  _ promiseA: Promise<A>,
+  _ promiseB: Promise<B>,
+  _ promiseC: Promise<C>
+) -> Promise<(A, B, C)> {
+  let promises = [
+    promiseA.objCPromise,
+    promiseB.objCPromise,
+    promiseC.objCPromise
+  ]
+  let promise = Promise<(A, B, C)>(
+    Promise<(A, B, C)>.ObjCPromise<AnyObject>.__onQueue(
+      queue,
+      all: promises
+    ).__onQueue(queue, then: { objCValues in
+      guard let values = objCValues as [AnyObject]?,
+            let valueA = Promise<A>.asValue(values[0]),
+            let valueB = Promise<B>.asValue(values[1]),
+            let valueC = Promise<C>.asValue(values[2])
+      else {
+        preconditionFailure("Cannot convert \(type(of: objCValues)) to \((A, B, C).self)")
+      }
+      return (valueA, valueB, valueC)
+    })
+  )
+  // Keep Swift wrapper alive for chained promises until `ObjCPromise` counterpart is resolved.
+  promises.forEach {
+    $0.__pendingObjects?.add(promise)
   }
   return promise
 }

Sources/Promises/Promise+Any.swift

@@ -41,12 +41,13 @@ public func any<Value>(
   on queue: DispatchQueue = .main,
   _ promises: [Promise<Value>]
 ) -> Promise<Value> {
+  let promises = promises.map { $0.objCPromise }
   let promise = Promise<Value>(
-    Promise<Value>.ObjCPromise<AnyObject>.__onQueue(queue, any: promises.map { $0.objCPromise })
+    Promise<Value>.ObjCPromise<AnyObject>.__onQueue(queue, any: promises)
   )
   // Keep Swift wrapper alive for chained promises until `ObjCPromise` counterpart is resolved.
   promises.forEach {
-    $0.objCPromise.__pendingObjects?.add(promise)
+    $0.__pendingObjects?.add(promise)
   }
   return promise
 }

Sources/Promises/Promise+Then.swift

@@ -29,8 +29,10 @@ public extension Promise {
   @discardableResult
   public func then<Result>(on queue: DispatchQueue = .main,
                            _ work: @escaping Then<Promise<Result>>) -> Promise<Result> {
-    let promise = Promise<Result>(objCPromise.__onQueue(queue, then: { value in
-      guard let value = Promise<Value>.asValue(value) else { preconditionFailure() }
+    let promise = Promise<Result>(objCPromise.__onQueue(queue, then: { objCValue in
+      guard let value = Promise<Value>.asValue(objCValue) else {
+        preconditionFailure("Cannot cast \(type(of: objCValue)) to \(Value.self)")
+      }
       do {
         return try work(value).objCPromise
       } catch let error {
@@ -52,8 +54,10 @@ public extension Promise {
   @discardableResult
   public func then<Result>(on queue: DispatchQueue = .main,
                            _ work: @escaping Then<Result>) -> Promise<Result> {
-    let promise = Promise<Result>(objCPromise.__onQueue(queue, then: { value in
-      guard let value = Promise<Value>.asValue(value) else { preconditionFailure() }
+    let promise = Promise<Result>(objCPromise.__onQueue(queue, then: { objCValue in
+      guard let value = Promise<Value>.asValue(objCValue) else {
+        preconditionFailure("Cannot cast \(type(of: objCValue)) to \(Value.self)")
+      }
       do {
         let value = try work(value)
         return value as? NSError ?? Promise<Result>.asAnyObject(value)
@@ -75,8 +79,10 @@ public extension Promise {
   /// - returns: A new pending promise to be resolved with the value passed into the `work` block.
   @discardableResult
   public func then(on queue: DispatchQueue = .main, _ work: @escaping Then<Void>) -> Promise {
-    let promise = Promise(objCPromise.__onQueue(queue, then: { value in
-      guard let value = Promise<Value>.asValue(value) else { preconditionFailure() }
+    let promise = Promise(objCPromise.__onQueue(queue, then: { objCValue in
+      guard let value = Promise<Value>.asValue(objCValue) else {
+        preconditionFailure("Cannot cast \(type(of: objCValue)) to \(Value.self)")
+      }
       do {
         try work(value)
         return Promise<Value>.asAnyObject(value)