fix: prevent race condition

Author: Tjalle-S

src/base/eventListeners.ts

@@ -6,7 +6,7 @@
  * (Department of Information and Computing Sciences)
  */
 import type { GraphQueryResult, MLResults, SchemaGraph, Settings } from ".";
-import type { ReceiveMessage, SendMessage } from "../internal";
+import type { ReadyMessage, ReceiveMessage, SendMessage } from "../internal";
 
 /**
  * Performs an action every time a message of the specified type is received.
@@ -36,7 +36,13 @@ export function receiveMessage<
     if (data.type === typeFilter) callback(data.data as TData);
   }
 
+  const readyMessage: ReadyMessage = {
+    data: undefined,
+    type: `${typeFilter}Ready`
+  };
+
   windowContext.addEventListener("message", updateMessage);
+  window.parent.postMessage(readyMessage, "*");
 
   return () => windowContext.removeEventListener("message", updateMessage);
 }

src/internal/message.types.ts

@@ -67,6 +67,16 @@ export interface SchemaMessage extends BaseMessage {
   type: "Schema";
 }
 
+/**
+ * A message that notifies the frontend that the add-on wants to receive data.
+ * 
+ * @internal
+ */
+export interface ReadyMessage extends BaseMessage {
+  data: undefined;
+  type: `${ReceiveMessage["type"]}Ready`;
+}
+
 /**
  * A message that is sent from the frontend to request the default config. The
  * response should be a {@link SettingsMessage}.
@@ -95,4 +105,4 @@ export type ReceiveMessage =
  *
  * @internal
  */
-export type SendMessage = SettingsMessage;
+export type SendMessage = SettingsMessage | ReadyMessage;

src/react/hooks.ts

@@ -137,7 +137,7 @@ export function useGraphData(): GraphQueryResult | undefined {
  * @remarks
  *   Component rerenders when the returned value changes.
  *
- * @returns A {@link ML} containing the results from the active machine learning
+ * @returns A {@link MLResults} containing the results from the active machine learning
  *   plugins.
  *
  * @category React hooks