fix: fire event should not throw for disabled handler (#470)

* updated tests

* feat: implement behavior chage

* code review changes

* refactor: more strict test conditions

Author: mdjastrzebski

src/__tests__/fireEvent.test.js

@@ -168,28 +168,28 @@ test('event with multiple handler parameters', () => {
 test('should not fire on disabled TouchableOpacity', () => {
   const handlePress = jest.fn();
   const screen = render(
-    <TouchableOpacity onPress={handlePress} disabled={true}>
-      <Text>Trigger</Text>
-    </TouchableOpacity>
+    <View>
+      <TouchableOpacity onPress={handlePress} disabled={true}>
+        <Text>Trigger</Text>
+      </TouchableOpacity>
+    </View>
   );
 
-  expect(() => fireEvent.press(screen.getByText('Trigger'))).toThrow(
-    'No handler function found for event: "press"'
-  );
+  fireEvent.press(screen.getByText('Trigger'));
   expect(handlePress).not.toHaveBeenCalled();
 });
 
 test('should not fire on disabled Pressable', () => {
   const handlePress = jest.fn();
   const screen = render(
-    <Pressable onPress={handlePress} disabled={true}>
-      <Text>Trigger</Text>
-    </Pressable>
+    <View>
+      <Pressable onPress={handlePress} disabled={true}>
+        <Text>Trigger</Text>
+      </Pressable>
+    </View>
   );
 
-  expect(() => fireEvent.press(screen.getByText('Trigger'))).toThrow(
-    'No handler function found for event: "press"'
-  );
+  fireEvent.press(screen.getByText('Trigger'));
   expect(handlePress).not.toHaveBeenCalled();
 });
 

src/fireEvent.js

@@ -6,30 +6,50 @@ const findEventHandler = (
   element: ReactTestInstance,
   eventName: string,
   callsite?: any,
-  nearestHostDescendent?: ReactTestInstance
+  nearestHostDescendent?: ReactTestInstance,
+  hasDescendandHandler?: boolean
 ) => {
+  const handler = getEventHandler(element, eventName);
+  const hasHandler = handler != null || hasDescendandHandler;
+
   const isHostComponent = typeof element.type === 'string';
   const hostElement = isHostComponent ? element : nearestHostDescendent;
   const isEventEnabled =
     hostElement?.props.onStartShouldSetResponder?.() !== false;
+  if (handler && isEventEnabled) return handler;
 
-  const eventHandlerName = toEventHandlerName(eventName);
+  // Do not bubble event to the root element
+  if (element.parent === null || element.parent.parent === null) {
+    if (hasHandler) {
+      return null;
+    } else {
+      throw new ErrorWithStack(
+        `No handler function found for event: "${eventName}"`,
+        callsite || invokeEvent
+      );
+    }
+  }
+
+  return findEventHandler(
+    element.parent,
+    eventName,
+    callsite,
+    hostElement,
+    hasHandler
+  );
+};
 
-  if (typeof element.props[eventHandlerName] === 'function' && isEventEnabled) {
+const getEventHandler = (element: ReactTestInstance, eventName: string) => {
+  const eventHandlerName = toEventHandlerName(eventName);
+  if (typeof element.props[eventHandlerName] === 'function') {
     return element.props[eventHandlerName];
-  } else if (typeof element.props[eventName] === 'function' && isEventEnabled) {
-    return element.props[eventName];
   }
 
-  // Do not bubble event to the root element
-  if (element.parent === null || element.parent.parent === null) {
-    throw new ErrorWithStack(
-      `No handler function found for event: "${eventName}"`,
-      callsite || invokeEvent
-    );
+  if (typeof element.props[eventName] === 'function') {
+    return element.props[eventName];
   }
 
-  return findEventHandler(element.parent, eventName, callsite, hostElement);
+  return undefined;
 };
 
 const invokeEvent = (