fix: strictly check if a given part of spec exists and render single message from oneOf

library/src/containers/Messages/Message.tsx

@@ -27,6 +27,10 @@ export const Message: React.FunctionComponent<Props> = ({
   index,
   showExamples = false,
 }) => {
+  if (!message) {
+    return null;
+  }
+
   const title = message.title();
   const summary = message.summary();
   const payload = message.payload();

library/src/containers/Messages/MessageExample.tsx

@@ -9,6 +9,10 @@ interface Props {
 }
 
 export const MessageExample: React.FunctionComponent<Props> = ({ message }) => {
+  if (!message) {
+    return null;
+  }
+
   const payload = message.payload();
   const headers = message.headers();
 

library/src/containers/Operations/Operation.tsx

@@ -20,6 +20,10 @@ export const Operation: React.FunctionComponent<Props> = ({
   channelName,
   channel,
 }) => {
+  if (!operation) {
+    return null;
+  }
+
   const parameters = SchemaHelpers.parametersToSchema(channel.parameters());
   const operationSummary = operation.summary();
 
@@ -107,7 +111,10 @@ export const Operation: React.FunctionComponent<Props> = ({
           <div className="mt-2">
             <p className="px-8">Accepts the following message:</p>
             <div className="mt-2">
-              <Message message={operation.message()} showExamples={true} />
+              <Message
+                message={(operation.message as any)(0)}
+                showExamples={true}
+              />
             </div>
           </div>
         )}

library/src/containers/Servers/Server.tsx

@@ -15,6 +15,10 @@ export const Server: React.FunctionComponent<Props> = ({
   serverName,
   server,
 }) => {
+  if (!server) {
+    return null;
+  }
+
   const urlVariables = SchemaHelpers.serverVariablesToSchema(
     server.variables(),
   );

playground/src/index.tsx

@@ -4,7 +4,6 @@ import ReactDOM from 'react-dom';
 import Playground from './Playground';
 
 import '@fortawesome/fontawesome-svg-core/styles.css';
-import '@asyncapi/react-component/lib/styles/fiori.css';
 import '@asyncapi/react-component/styles/default.min.css';
 import './common/icons';