Merge pull request #3500 from danielearwicker/master

Use union types (TS 1.4) for ko.unwrap and ko.utils.unwrapObservable

knockout/knockout.d.ts

@@ -306,7 +306,7 @@ interface KnockoutUtils {
 
     triggerEvent(element: any, eventType: any): void;
 
-    unwrapObservable<T>(value: KnockoutObservable<T>): T;
+    unwrapObservable<T>(value: KnockoutObservable<T> | T): T;
 
     peekObservable<T>(value: KnockoutObservable<T>): T;
 
@@ -442,7 +442,7 @@ interface KnockoutStatic {
     cleanNode(node: Element): Element;
     renderTemplate(template: Function, viewModel: any, options?: any, target?: any, renderMode?: any): any;
     renderTemplate(template: string, viewModel: any, options?: any, target?: any, renderMode?: any): any;
-	unwrap(value: any): any;
+	unwrap<T>(value: KnockoutObservable<T> | T): T;
 
 	computedContext: KnockoutComputedContext;
 

knockout/tests/knockout-tests.ts

@@ -648,4 +648,11 @@ function test_Components() {
         // Empty config for registering custom elements that are handled by name convention
 		ko.components.register('name', { /* No config needed */ });
     }
+}
+
+function testUnwrapUnion() {
+    
+    var possibleObs: KnockoutObservable<number> | number;
+    var num = ko.unwrap(possibleObs);
+
 }