Roll Polymer

third_party/polymer/v1_0/components-chromium/app-route/app-route-extracted.js

 'use strict';
 
   Polymer({
     is: 'app-route',
 
     properties: {
       /**
        * The URL component managed by this element.
        */
       route: {
@@ skipping 69 matching lines @@
       '__routeQueryParamsChanged(route.__queryParams)',
       '__tailQueryParamsChanged(tail.__queryParams)',
       '__queryParamsChanged(queryParams.*)'
     ],
 
     created: function() {
       this.linkPaths('route.__queryParams', 'tail.__queryParams');
       this.linkPaths('tail.__queryParams', 'route.__queryParams');
     },
 
-    // IE Object.assign polyfill
-    __assign: function(target, source) {
-      if (Object.assign) {
-        return Object.assign(target, source);
-      }
-      if (source != null) {
-        for (var key in source) {
-          target[key] = source[key];
-        }
-      }
-
-      return target;
-    },
-
     /**
      * Deal with the query params object being assigned to wholesale.
      * @export
      */
     __routeQueryParamsChanged: function(queryParams) {
       if (queryParams && this.tail) {
         this.set('tail.__queryParams', queryParams);
 
         if (!this.active || this._queryParamsUpdating) {
           return;
         }
 
+        // Copy queryParams and track whether there are any differences compared
+        // to the existing query params.
+        var copyOfQueryParams = {};
+        var anythingChanged = false;
+        for (var key in queryParams) {
+          copyOfQueryParams[key] = queryParams[key];
+          if (anythingChanged ||
+              !this.queryParams ||
+              queryParams[key] !== this.queryParams[key]) {
+            anythingChanged = true;
+          }
+        }
+        // Need to check whether any keys were deleted
+        for (var key in this.queryParams) {
+          if (anythingChanged || !(key in queryParams)) {
+            anythingChanged = true;
+            break;
+          }
+        }
+
+        if (!anythingChanged) {
+          return;
+        }
         this._queryParamsUpdating = true;
-        this.set('queryParams', this.__assign({}, queryParams));
+        this.set('queryParams', copyOfQueryParams);
         this._queryParamsUpdating = false;
       }
     },
 
     /**
      * @export
      */
     __tailQueryParamsChanged: function(queryParams) {
       if (queryParams && this.route) {
         this.set('route.__queryParams', queryParams);
@@ skipping 173 matching lines @@
       for (var property in setObj) {
         this._propertySetter(property, setObj[property]);
       }
 
       for (var property in setObj) {
         this._pathEffector(property, this[property]);
         this._notifyPathUp(property, this[property]);
       }
     }
   });