ko.unwrap uses union types

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);
+
 }