204 NO CONTENT regression fix

CHANGELOG.md

@@ -2,6 +2,10 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+### Fixed
+- Fix regression on handling PreventUpdate (204 NO CONTENT) [#170](https://github.com/plotly/dash-renderer/pull/170)
+
 ## [0.23.0] - 2019-04-25
 ### Fixed
 - Fix regression for `children=0` case [#148](https://github.com/plotly/dash-renderer/issues/148)

src/actions/index.js

@@ -674,13 +674,18 @@ function updateOutput(
                 // update the status of this request
                 updateRequestQueue(true, res.status);
 
+                /*
+                 * This is a 204 response code, there's no content to process.
+                 */
+                if (res.status === STATUS.PREVENT_UPDATE) {
+                    return;
+                }
+
                 /*
                  * eject into `catch` handler below to display error
                  * message in ui
                  */
-                if (res.status !== STATUS.PREVENT_UPDATE) {
-                    throw res;
-                }
+                throw res;
             }
 
             /*

tests/test_render.py

@@ -329,7 +329,7 @@ def update_input(value):
             'lxml').select_one('#output > div').contents
 
         self.assertTrue(
-            pad_input.attrs == {'id': 'sub-input-1', 'value': 'sub input initial value'}
+            pad_input.attrs == {'type': 'text', 'id': 'sub-input-1', 'value': 'sub input initial value'}
                 and pad_input.name == 'input',
             "pad input is correctly rendered")