optimization: avoid use of Map in hot path in favor of array with duplicates.

src/properties/property-effects.html

@@ -46,7 +46,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
   /**
    * Ensures that the model has an own-property map of effects for the given type.
    * The model may be a prototype or an instance.
-   * 
+   *
    * Property effects are stored as arrays of effects by property in a map,
    * by named type on the model. e.g.
    *
@@ -58,7 +58,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    * If the model does not yet have an effect map for the type, one is created
    * and returned.  If it does, but it is not an own property (i.e. the
    * prototype had effects), the the map is deeply cloned and the copy is
-   * set on the model and returned, ready for new effects to be added. 
+   * set on the model and returned, ready for new effects to be added.
    *
    * @param {Object} model Prototype or instance
    * @param {string} type Property effect type
@@ -214,7 +214,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
   }
 
   /**
-   * Dispatches {property}-changed events with path information in the detail 
+   * Dispatches {property}-changed events with path information in the detail
    * object to indicate a sub-path of the property was changed.
    *
    * @param {Element} inst The element from which to fire the event
@@ -297,7 +297,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    * @param {Event} e Notification event (e.g. '<property>-changed')
    * @param {Object} inst Host element instance handling the notification event
    * @param {string} property Child element property that was bound
-   * @param {string} path Host property/path that was bound 
+   * @param {string} path Host property/path that was bound
    * @param {boolean} negate Whether the binding was negated
    * @private
    */
@@ -430,7 +430,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    * @param {Object} computedProps Bag of properties newly computed this turn
    *   via "computed" effects; any linked paths generated via this method
    *   will be added both to the set of `changedProps` as well as to the
-   *   set of `computedProps`; this is because the `fromAbove: true` case will 
+   *   set of `computedProps`; this is because the `fromAbove: true` case will
    *   notify only from the `computedProps` bag.
    * @private
    */
@@ -670,7 +670,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    * - Memoizes the root property for path bindings
    * - Recurses into nested templates and processes those templates and
    *   extracts any host properties, which are set to the template's
-   *   `_content._hostProps` 
+   *   `_content._hostProps`
    * - Adds bindings from the host to <template> elements for any nested
    *   template's lexically bound "host properties"; template handling
    *   elements can then add accessors to the template for these properties
@@ -1052,7 +1052,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    *
    * The `path` and `value` arguments are used to fill in wildcard descriptor
    * when the method is being called as a result of a path notification.
-   * 
+   *
    * @param {Object} data Instance data storage object to read properties from
    * @param {Array<Object>} args Array of argument metadata
    * @return {Array<*>} Array of argument values
@@ -1096,7 +1096,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    * Initializes `__dataCompoundStorage` local storage on a bound node with
    * initial literal data for compound bindings, and sets the joined
    * literal parts to the bound property.
-   * 
+   *
    * When changes to compound parts occur, they are first set into the compound
    * storage array for that property, and then the array is joined to result in
    * the final value set to the property/attribute.
@@ -1137,7 +1137,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
   // data api
 
   /**
-   * Sends array splice notifications (`.splices` and `.length`) 
+   * Sends array splice notifications (`.splices` and `.length`)
    *
    * Note: this implementation only accepts normalized paths
    *
@@ -1369,7 +1369,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
        *
        * If `path` is an unmanaged property (property without an accessor)
        * or a path, sets the value at that path.
-       * 
+       *
        * `path` can be a path string or array of path parts as accepted by the
        * public API.
        *
@@ -1406,7 +1406,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
           if (!super._shouldPropertyChange(path, value, old)) {
             return null;
           }
-        } 
+        }
         if (hasEffect) {
           return path;
         }
@@ -1472,7 +1472,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 
       /**
        * Overrides default PropertyAccessors implementation to pull the value
-       * to dirty check against from the `__dataTemp` cache (rather than the 
+       * to dirty check against from the `__dataTemp` cache (rather than the
        * normal `__data` cache) for Objects.  Since the temp cache is cleared
        * at the end of a turn, this implementation allows side-effects of deep
        * object changes to be processed by re-setting the same object (using
@@ -1492,12 +1492,12 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
       }
 
       /**
-       * Overrides PropertyAccessor's default async queuing of 
+       * Overrides PropertyAccessor's default async queuing of
        * `_propertiesChanged`: if `__dataInitialized` is false (has not yet been
        * manually flushed), the function no-ops; otherwise flushes
        * `_propertiesChanged` synchronously.
        *
-       * Subclasses may set `this._asyncEffects = true` to cause 
+       * Subclasses may set `this._asyncEffects = true` to cause
        * `_propertiesChanged` to be flushed asynchronously.
        *
        * @override
@@ -1521,9 +1521,9 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
        * @protected
        */
       _enqueueClient(client) {
-        this.__dataPendingClients = this.__dataPendingClients || new Map();
+        this.__dataPendingClients = this.__dataPendingClients || [];
         if (client !== this) {
-          this.__dataPendingClients.set(client, true);
+          this.__dataPendingClients.push(client);
         }
       }
 
@@ -1538,12 +1538,13 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
         let clients = this.__dataPendingClients;
         if (clients) {
           this.__dataPendingClients = null;
-          clients.forEach((v, client) => {
+          for (let i=0; i < clients.length; i++) {
+            let client = clients[i];
             // TODO(kschaaf): more explicit check?
-            if (client._flushProperties) {
+            if (!client.__dataInitialized || client.__dataPending) {
               client._flushProperties(true);
             }
-          });
+          }
         }
       }
 
@@ -1567,7 +1568,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
         this._invalidateProperties();
       }
       /**
-       * Overrides PropertyAccessor's default async queuing of 
+       * Overrides PropertyAccessor's default async queuing of
        * `_propertiesChanged`, to instead synchronously flush
        * `_propertiesChanged` unless the `this._asyncEffects` property is true.
        *
@@ -1627,7 +1628,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
        * listeners, and the `this.$` map of `id`'s to nodes.  A document fragment
        * is returned containing the stamped DOM, ready for insertion into the
        * DOM.
-       * 
+       *
        * Note that for host data to be bound into the stamped DOM, the template
        * must have been previously bound to the prototype via a call to
        * `_bindTemplate`, which performs one-time template binding work.
@@ -1801,7 +1802,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
             if ((path = this._setPathOrUnmanagedProperty(path, value))) {
               this._setProperty(path, value);
             }
-          }          
+          }
         }
       }
 
@@ -1972,7 +1973,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
        * Creates a read-only accessor for the given property.
        *
        * To set the property, use the protected `_setProperty` API.
-       * To create a custom protected setter (e.g. `_setMyProp()` for 
+       * To create a custom protected setter (e.g. `_setMyProp()` for
        * property `myProp`), pass `true` for `protectedSetter`.
        *
        * Note, if the property will have other property effects, this method