Merge pull request #4574 from ChadKillingsworth/observer-function

Support property observers which are direct function references
Polymer · Dec 1, 2017 · 0c185b5 · 0c185b5
2 parents b124b70 + 4bae2b6
commit 0c185b5
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Showing 2 changed files with 11 additions and 11 deletions.
diff --git a/lib/mixins/property-effects.html b/lib/mixins/property-effects.html
@@ -209,12 +209,12 @@
    * @private
    */
   function runObserverEffect(inst, property, props, oldProps, info) {
-    let fn = inst[info.methodName];
+    let fn = typeof info.method === "string" ? inst[info.method] : info.method;
     let changedProp = info.property;
     if (fn) {
       fn.call(inst, inst.__data[changedProp], oldProps[changedProp]);
     } else if (!info.dynamicFn) {
-      console.warn('observer method `' + info.methodName + '` not defined');
+      console.warn('observer method `' + info.method + '` not defined');
     }
   }
 
@@ -2023,20 +2023,20 @@
        * full API docs.
        *
        * @param {string} property Property name
-       * @param {string} methodName Name of observer method to call
+       * @param {string|function(*,*)} method Function or name of observer method to call
        * @param {boolean=} dynamicFn Whether the method name should be included as
        *   a dependency to the effect.
        * @return {void}
        * @protected
        */
-      _createPropertyObserver(property, methodName, dynamicFn) {
-        let info = { property, methodName, dynamicFn: Boolean(dynamicFn) };
+      _createPropertyObserver(property, method, dynamicFn) {
+        let info = { property, method, dynamicFn: Boolean(dynamicFn) };
         this._addPropertyEffect(property, TYPES.OBSERVE, {
           fn: runObserverEffect, info, trigger: {name: property}
         });
         if (dynamicFn) {
-          this._addPropertyEffect(methodName, TYPES.OBSERVE, {
-            fn: runObserverEffect, info, trigger: {name: methodName}
+          this._addPropertyEffect(method, TYPES.OBSERVE, {
+            fn: runObserverEffect, info, trigger: {name: method}
           });
         }
       }
@@ -2169,14 +2169,14 @@
        * Creates a single-property observer for the given property.
        *
        * @param {string} property Property name
-       * @param {string} methodName Name of observer method to call
+       * @param {string|function(*,*)} method Function or name of observer method to call
        * @param {boolean=} dynamicFn Whether the method name should be included as
        *   a dependency to the effect.
        * @return {void}
        * @protected
        */
-      static createPropertyObserver(property, methodName, dynamicFn) {
-        this.prototype._createPropertyObserver(property, methodName, dynamicFn);
+      static createPropertyObserver(property, method, dynamicFn) {
+        this.prototype._createPropertyObserver(property, method, dynamicFn);
       }
 
       /**

diff --git a/test/unit/property-effects-elements.html b/test/unit/property-effects-elements.html
@@ -509,7 +509,7 @@
       },
       prop2: {
         value: 'default',
-        observer: 'prop2Changed'
+        observer: function(newProp, oldProp) { return this.prop2Changed(newProp, oldProp); }
       }
     },
     created: function() {