Fixes #4478 by adding a better warning for attributes that cannot des…

…erialize from JSON.
Polymer · Apr 6, 2017 · dba28c0 · dba28c0
1 parent 7836e6c
commit dba28c0
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/lib/mixins/property-accessors.html b/lib/mixins/property-accessors.html
@@ -307,7 +307,7 @@
               outValue = JSON.parse(value);
             } catch(x) {
               outValue = null;
-              console.warn('Polymer::Attributes: couldn`t decode Array as JSON');
+              console.warn(`Polymer::Attributes: couldn't decode Array as JSON: ${value}`);
             }
             break;
 

diff --git a/test/unit/attributes.html b/test/unit/attributes.html
@@ -212,6 +212,15 @@
       assert.strictEqual(element.dashCase, 'Changed');
     });
 
+    test('value that cannot deserialize from JSON warns', function() {
+      sinon.spy(console, 'warn');
+      var badAttr = '[foo, bar]';
+      element.setAttribute('array', badAttr);
+      assert.isTrue(console.warn.calledOnce);
+      assert.include(console.warn.firstCall.args[0], badAttr);
+      console.warn.restore();
+    });
+
   });
 
   suite('imperative attribute change (reflect)', function() {