fixes #194 able to read the internal observed value

Author: justinbmeyer

Diff for: scope-key-data.js

@@ -29,6 +29,7 @@ var dispatchSymbol = canSymbol.for("can.dispatch");
 // this work.
 
 var peekValue = ObservationRecorder.ignore(canReflect.getValue.bind(canReflect));
+var peekGet = ObservationRecorder.ignore(Observation.prototype.get);
 
 var getFastPathRoot = ObservationRecorder.ignore(function(computeData){
 	if( computeData.reads &&
@@ -112,6 +113,10 @@ var ScopeKeyData = function(scope, key, options){
 	var valueDependencies = new Set();
 	valueDependencies.add(observation);
 	this.dependencies = {valueDependencies: valueDependencies};
+
+	// This is basically what .get() should give, but it
+	// isn't used to figure out the last value.
+	this._latestValue = undefined;
 };
 
 valueEventBindings(ScopeKeyData.prototype);
@@ -128,7 +133,7 @@ assign(ScopeKeyData.prototype, {
 	constructor: ScopeKeyData,
 	dispatch: function dispatch(newVal){
 		var old = this.value;
-		this.value = newVal;
+		this._latestValue = this.value = newVal;
 		// call the base implementation in can-event-queue
 		this[dispatchSymbol].call(this, this.value, old);
 	},
@@ -141,7 +146,7 @@ assign(ScopeKeyData.prototype, {
 			// rewrite the observation to call its event handlers
 			this.toFastPath(fastPathRoot);
 		}
-		this.value = peekValue(this.observation);
+		this._latestValue = this.value = peekGet.call(this.observation);
 	},
 	onUnbound: function onUnbound() {
 		this.bound = false;
@@ -168,10 +173,10 @@ assign(ScopeKeyData.prototype, {
 			}
 		}
 
-		if (this.bound === true ) {
-			return this.value;
+		if (this.bound === true && this.fastPath === true) {
+			return this._latestValue;
 		} else {
-			return this.observation.get();
+			return peekGet.call(this.observation);
 		}
 	},
 	toFastPath: function(fastPathRoot){
@@ -188,6 +193,7 @@ assign(ScopeKeyData.prototype, {
 			// but I think we will be able to get at it b/c there should only be one
 			// dependency we are binding to ...
 			if(target === fastPathRoot && typeof newVal !== "function") {
+				self._latestValue = newVal;
 				this.newVal = newVal;
 			} else {
 				// restore

Diff for: test/scope-key-data-test.js

@@ -46,3 +46,42 @@ QUnit.test("ScopeKeyData's thisArg is observable", function(){
 		value: "B"
 	});
 });
+
+QUnit.test("reading ScopeKeyData will update underlying observable", function(){
+	var context = new SimpleMap({
+		"prop" :"value"
+	});
+
+	var prop = new Scope(context).computeData("this.prop",{proxyMethods: false});
+
+	canReflect.onValue(prop, function(){});
+
+	context.on("prop", function(){
+
+		QUnit.equal(canReflect.getValue(prop), "VALUE", "able to read fastPath value");
+	},"notify");
+
+	context.set("prop", "VALUE");
+
+
+	var root = new SimpleObservable("value");
+	var observation = new Observation(function(){
+		return root.value;
+	});
+
+	context = {
+		"prop" : observation
+	};
+
+	prop = new Scope(context).computeData("this.prop",{proxyMethods: false});
+
+	canReflect.onValue(prop, function(){});
+
+
+	canReflect.onValue(root, function(){
+
+		QUnit.equal(canReflect.getValue(prop), "VALUE", "able to read deep, non-fast-path value");
+	},"notify");
+
+	root.value = "VALUE";
+});

Diff for: test/scope-test.js

@@ -631,7 +631,7 @@ QUnit.test("./ scope lookup should read current scope", function () {
 	var parent = new SimpleMap();
 	var map = new SimpleMap();
 	var scope = new Scope(parent).add(map);
-	QUnit.equal(scope.attr("./"), map);
+	QUnit.equal(scope.get("./"), map);
 });
 
 QUnit.test("getTemplateContext() gives a scope with the templateContext", function() {