Property updates

Sources/Foundation/NSObject+Jetpack.swift

@@ -117,7 +117,7 @@ fileprivate class PropertyActionHandler<Base: AnyObject, T>: NSObject {
         self.getter = getter
         self.base = base
         self.cleanup = cleanup
-        property = Property(signal: signal) {
+        property = Property(signal.asObserver) {
             getter(base)
         }
     }

Sources/Observable+Commit.swift

@@ -19,7 +19,7 @@ extension Observable {
         }
 
         if immediateResult != nil {
-            let prop = Property<ValueType>(signal: signal) {
+            let prop = Property<ValueType>(signal.asObserver) {
                 return immediateResult!
             }
             return (prop.asObserver, disposable)

Sources/Property.swift

@@ -11,22 +11,32 @@ import Foundation
 public final class Property<T>: Observable {
     public typealias ValueType = T
 
-    private let signal: Signal<T>
+    private let observer: Observer<T>
     private let getter: ()->T
 
     public var value: T {
         return getter()
     }
 
-    public init(signal: Signal<T>, getter: @escaping ()->T) {
+    public init(_ observer: Observer<T>, getter: @escaping ()->T) {
         self.getter = getter
-        self.signal = signal
+        self.observer = observer
+    }
+
+    public convenience init(constant: T) {
+        self.init(Observer.from(constant), getter: { constant })
     }
 
     @discardableResult
     public func subscribe(_ observer: @escaping (T) -> Void) -> Disposable {
         observer(value)
-        return signal.subscribe(observer)
+        return self.observer.subscribe(observer)
+    }
+
+    public func map<U>(_ transform: @escaping (T) -> U) -> Property<U> {
+        return Property<U>(observer.map(transform)) {
+            transform(self.getter())
+        }
     }
 }
 

Sources/State.swift

@@ -23,7 +23,7 @@ public final class State<T>: Observable, Bindable {
         let signal = Signal<T>()
         var v = value
 
-        property = Property(signal: signal) {
+        property = Property(signal.asObserver) {
             return v
         }
         variable = Variable(setter: {