UIDS-24 Add initial state and clear messages

Author: Rachel Roppolo

spec/Flash/useFlash.test.js

@@ -66,4 +66,23 @@ describe('useFlash', () => {
       })),
     );
   });
+
+  test('can clear all messages', () => {
+    const messages = ['A new', 'message'].map(
+      (msg, i) => ({
+          id: i,
+          type: MessageTypes.SUCCESS,
+          message: msg,
+        }),
+    );
+
+    const { result } = renderHook(() => useFlash(messages));
+    expect(result.current.messages.length).toEqual(2);
+
+    act(() => {
+      result.current.clearMessages();
+    });
+
+    expect(result.current.messages.length).toEqual(0);
+  });
 });

src/Flash/index.js

@@ -1,8 +1,10 @@
+import Flash from './Flash';
 import { MessageTypes } from './FlashMessage';
 import useFlash from './useFlash';
 import withFlash, { withFlashPropTypes } from './withFlash';
 
 export {
+  Flash,
   MessageTypes,
   useFlash,
   withFlash,

src/Flash/useFlash.js

@@ -7,8 +7,12 @@ const createMessage = (messageType, messageText) => ({
   type: messageType,
 });
 
-const useFlash = () => {
-  const [messages, setMessages] = useState([]);
+const useFlash = (initialMessages = []) => {
+  const [messages, setMessages] = useState(initialMessages);
+
+  const clearMessages = () => {
+    setMessages([]);
+  };
 
   const setMessage = (messageType, messageText) => {
     setMessages([
@@ -25,6 +29,7 @@ const useFlash = () => {
 
   return {
     messages,
+    clearMessages,
     setMessage,
     dismissMessage,
   };