Merge pull request #158 from UrbanCompass/tim/add_variable_map

Re-add Variable map

Snail/Extensions/URLSessionExtensions.swift

@@ -20,8 +20,8 @@ extension URLSession {
     }
 
     private static var disposerKey = "com.compass.Snail.URLSession.Disposer"
-    
-    var disposer: Disposer {
+
+    public var disposer: Disposer {
         if let disposer = objc_getAssociatedObject(self, &URLSession.disposerKey) as? Disposer {
             return disposer
         }

Snail/Replay.swift

@@ -40,8 +40,8 @@ public class Replay<T>: Observable<T> {
 
     private func replay(queue: DispatchQueue?, handler: @escaping (Event<T>) -> Void) {
         eventsQueue.sync {
-            self.events.forEach {
-                event in notify(subscriber: Subscriber(queue: queue, observable: self, handler: handler), event: event)
+            self.events.forEach { event in
+                notify(subscriber: Subscriber(queue: queue, observable: self, handler: handler), event: event)
             }
         }
     }

Snail/Variable.swift

@@ -6,6 +6,7 @@ public class Variable<T> {
     let subject: Replay<T>
     var lock = NSRecursiveLock()
     var currentValue: T
+    private let disposer = Disposer()
 
     public var value: T {
         get {
@@ -37,6 +38,15 @@ public class Variable<T> {
         })
     }
 
+    public func map<U>(_ transform: @escaping (T) -> U) -> Variable<U> {
+        let newVariable = Variable<U>(transform(value))
+        asObservable().subscribe(onNext: { [weak self] _ in
+            guard let self = self else { return }
+            newVariable.value = transform(self.value)
+        }).add(to: disposer)
+        return newVariable
+    }
+
     deinit {
         subject.on(.done)
     }

SnailTests/VariableTests.swift

@@ -45,7 +45,7 @@ class VariableTests: XCTestCase {
         subject.value = "new"
         var subjectCharactersCount: Int?
 
-        subject.asObservable().subscribe(onNext: { val in subjectCharactersCount = val.count }).add(to: disposer)
+        subject.map { $0.count }.asObservable().subscribe(onNext: { subjectCharactersCount = $0 }).add(to: disposer)
 
         XCTAssertEqual(subject.value.count, subjectCharactersCount)
     }
@@ -54,7 +54,7 @@ class VariableTests: XCTestCase {
         let subject = Variable("initial")
         var subjectCharactersCount: Int?
 
-        subject.asObservable().subscribe(onNext: { val in subjectCharactersCount = val.count }).add(to: disposer)
+        subject.map { $0.count }.asObservable().subscribe(onNext: { subjectCharactersCount = $0 }).add(to: disposer)
 
         XCTAssertEqual(subject.value.count, subjectCharactersCount)
     }
@@ -63,7 +63,7 @@ class VariableTests: XCTestCase {
         let subject = Unique("sameValue")
         var firedCount = 0
 
-        subject.asObservable().subscribe(onNext: { _ in
+        subject.map { $0.count }.asObservable().subscribe(onNext: { _ in
             firedCount += 1
         }).add(to: disposer)
 
@@ -76,7 +76,7 @@ class VariableTests: XCTestCase {
         let subject = Variable("sameValue")
         var firedCount = 0
 
-        subject.asObservable().subscribe(onNext: { _ in
+        subject.map { $0.count }.asObservable().subscribe(onNext: { _ in
             firedCount += 1
         }).add(to: disposer)
 
@@ -85,6 +85,17 @@ class VariableTests: XCTestCase {
         XCTAssertEqual(firedCount, 2)
     }
 
+    func testMapToVoid() {
+        let subject = Variable("initial")
+        var fired = false
+
+        subject.map { _ in return () }.asObservable().subscribe(onNext: { _ in
+            fired = true
+        }).add(to: disposer)
+
+        XCTAssertTrue(fired)
+    }
+
     func testBindToOtherVariable() {
         let subject = Variable("one")
         let observedVariable = Variable("two")