Add deliver() and discardChanges() methods to Stateful.

Previously they were just in Invalidating.

The new methods call deliver() and discardChanges() on every listener registered via
Stateful#observe().

Invalidating has a minor behavior change: deliver() and discardChanges() now affect every listener
registered via observe(), not just the two listeners registered by Invalidating itself.

Fixes #42.

Author: wkeese

Invalidating.js

@@ -51,25 +51,6 @@ define([
 			return this._hComputing;
 		},
 
-		/**
-		 * Synchronously deliver change records for computed properties and then UI rendering
-		 * so that `refreshingRendering()` is called if there are pending change records.
-		 */
-		deliver: function () {
-			this._hComputing && this._hComputing.deliver();
-			this._hRendering && this._hRendering.deliver();
-			return this._hComputing;
-		},
-
-		/**
-		 * Discard change records.
-		 */
-		discardChanges: function () {
-			this._hComputing && this._hComputing.discardChanges();
-			this._hRendering && this._hRendering.discardChanges();
-			return this._hComputing;
-		},
-
 		/**
 		 * Callback function to calculate computed properties upon property changes.
 		 * @param {Object} newValues The hash table of new property values, keyed by property names.

Stateful.js

@@ -1,9 +1,10 @@
 /** @module decor/Stateful */
 define([
+	"dcl/advise",
 	"dcl/dcl",
 	"./features",
 	"./Observable"
-], function (dcl, has, Observable) {
+], function (advise, dcl, has, Observable) {
 	var apn = {};
 
 	/**
@@ -215,6 +216,15 @@ define([
 			}, this);
 		},
 
+		/**
+		 * Get list of properties that Stateful#observe() should observe.
+		 * @returns {string[]} list of properties
+		 * @protected
+		 */
+		getPropsToObserve: function () {
+			return this.constructor._props;
+		},
+
 		/**
 		 * Observes for change in properties.
 		 * Callback is called at the end of micro-task of changes with a hash table of
@@ -246,9 +256,31 @@ define([
 		 *     stateful.baz = 10;
 		 */
 		observe: function (callback) {
-			var h = new Stateful.PropertyListObserver(this, this.constructor._props);
+			// create new listener
+			var h = new Stateful.PropertyListObserver(this, this.getPropsToObserve());
 			h.open(callback, this);
+
+			// make this.deliver() and this.discardComputing() call deliver() and discardComputing() on new listener
+			var a1 = advise.after(this, "deliver", h.deliver.bind(h)),
+				a2 = advise.after(this, "discardChanges", h.discardChanges.bind(h));
+			advise.before(h, "close", function () {
+				a1.unadvise();
+				a2.unadvise();
+			});
+
 			return h;
+		},
+
+		/**
+		 * Synchronously deliver change records to all listeners registered via `observe()`.
+		 */
+		deliver: function () {
+		},
+
+		/**
+		 * Discard change records for all listeners registered via `observe()`.
+		 */
+		discardChanges: function () {
 		}
 	});
 

tests/unit/Stateful.js

@@ -358,6 +358,35 @@ define([
 			hObserve.deliver();
 			assert.deepEqual(changes, [{foo: "Foo1"}]);
 		},
+		"Stateful#deliver(), Stateful#discardChanges()": function () {
+			var stateful = new (dcl(Stateful, {
+				foo: undefined,
+				bar: undefined
+			}))({
+				foo: "Foo0",
+				bar: "Bar0"
+			});
+			var log = "";
+			stateful.observe(function () {
+				log += "first";
+			});
+			stateful.observe(function () {
+				log += ", second";
+			});
+			stateful.foo = "Foo1";
+			stateful.bar = "Bar1";
+			stateful.deliver();
+			assert.strictEqual(log, "first, second", "deliver()");
+
+			log = "";
+			stateful.foo = "Foo2";
+			stateful.bar = "Bar2";
+			stateful.discardChanges();
+			stateful.deliver();
+			setTimeout(this.async().callback(function () {
+				assert.strictEqual(log, "", "discardChanges()");
+			}), 10);
+		},
 		"observe filter": function () {
 			// Check to make sure reported changes are consistent between platforms with and without Object.observe()
 			// native support
@@ -386,7 +415,6 @@ define([
 			stateful.foo = 22;
 			stateful.anotherFunc = function () { };
 			stateful.instanceProp = 33;
-		},
-
+		}
 	});
 });