Merge pull request #571 from PolymerElements/reset-attached

Reset threshold-triggered on attached

Author: keanulee

app-scroll-effects/app-scroll-effects-behavior.js

@@ -227,6 +227,10 @@ export const AppScrollEffectsBehavior = [
       return Math.max(0, this._scrollTop);
     },
 
+    attached: function() {
+      this._scrollStateChanged();
+    },
+
     detached: function() {
       this._tearDownEffects();
     },
@@ -368,6 +372,10 @@ export const AppScrollEffectsBehavior = [
      * Overrides the `_scrollHandler`.
      */
     _scrollHandler: function() {
+      this._scrollStateChanged();
+    },
+
+    _scrollStateChanged: function() {
       if (!this.disabled) {
         var scrollTop = this._clampedScrollTop;
         this._updateScrollState(scrollTop);

app-scroll-effects/test/app-scroll-effects-behavior.html

@@ -225,6 +225,35 @@
           ]);
         });
       });
+
+      test('reset threshold-triggered on attached (#570)', function(done) {
+        flush(function() {
+          var parent = container.parentElement;
+          assert.isUndefined(container.thresholdTriggered);
+          assert.equal(container.threshold, 0);
+          container.threshold = 100;
+
+          scrollTestHelper(container.scrollTarget, [
+            {
+              y: 100,
+              callback: function() {
+                assert.isTrue(container.thresholdTriggered);
+                parent.removeChild(container);
+                assert.isTrue(container.thresholdTriggered);
+              }
+            },
+            {
+              y: 0,
+              callback: function() {
+                assert.isTrue(container.thresholdTriggered);
+                parent.appendChild(container);
+                assert.isFalse(container.thresholdTriggered);
+                done();
+              }
+            }
+          ]);
+        });
+      });
     });
   </script>