fix wheel event handler Violation in Chromium by setting passive: true

emilykl · emilykl · commit 2f65ccd114ce · 2025-08-08T15:53:09.000-04:00
diff --git a/src/lib/events.js b/src/lib/events.js
@@ -59,15 +59,9 @@ var Events = {
             internalEv.emit(event, data);
         };
 
-        /*
-         * Add a dummy event handler for 'wheel' event for Safari
-         * to enable mouse wheel zoom.
-         * https://github.com/d3/d3/issues/3035
-         * https://github.com/plotly/plotly.js/issues/7452
-         */
-        if(typeof plotObj.addEventListener === 'function') {
-            plotObj.addEventListener("wheel", () => {});
-        }
+        // Add a dummy event handler for 'wheel' event for Safari
+        // to enable mouse wheel zoom.
+        addDummyScrollEventListener(plotObj);
 
         return plotObj;
     },
@@ -140,4 +134,35 @@ var Events = {
 
 };
 
+function addDummyScrollEventListener(plotObj) {
+    /*
+     * Add a dummy event handler for 'wheel' event for Safari
+     * to enable mouse wheel zoom.
+     * https://github.com/d3/d3/issues/3035
+     * https://github.com/plotly/plotly.js/issues/7452
+     *
+     * We set {passive: true} for better performance
+     * and to avoid a Violation warning in Chromium.
+     * https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md
+     * https://github.com/plotly/plotly.js/issues/7516
+     */
+
+    // Test whether the passive property is accessed (for compatibility with older browsers)
+    var supportsPassive = false;
+    try {
+        var opts = Object.defineProperty({}, 'passive', {
+            get: function() {
+                supportsPassive = true;
+            }
+        });
+        window.addEventListener("testPassive", null, opts);
+        window.removeEventListener("testPassive", null, opts);
+    } catch (e) {}
+
+    if(typeof plotObj.addEventListener === 'function') {
+        plotObj.addEventListener("wheel", () => {}, supportsPassive ? { passive: true } : false);
+    }
+
+}
+
 module.exports = Events;
