fix: prevent race condition

src/base/eventListeners.ts

@@ -6,7 +6,7 @@
  * (Department of Information and Computing Sciences)
  */
 import type { 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.
@@ -36,12 +36,17 @@ export function receiveMessage<
     if (data.type === typeFilter) callback(data.data as TData);
   }
 
+  const readyMessage: ReadyMessage = {
+    data: undefined,
+    type: `${typeFilter}Ready`
+  };
+
   windowContext.addEventListener("message", updateMessage);
+  sendMessage(readyMessage);
 
   return () => windowContext.removeEventListener("message", updateMessage);
 }
 
-
 /**
  * Performs an action every time a message with settings is received.
  *

src/base/index.ts

@@ -8,7 +8,7 @@
 
 /**
  * @packageDocumentation Contains the basic GraphPolaris ml settings plugin API. This is required for any plugin, regardless of the framework used.
-
+ *
  * @categoryDescription Message event listeners
  * These are functions to listen for specific types of messages arriving.
  */

src/internal/message.types.ts

@@ -6,9 +6,7 @@
  * (Department of Information and Computing Sciences)
  */
 
-import type {
-  Settings
-} from "../base";
+import type { Settings } from "../base";
 
 /**
  * The base message type for all messages.
@@ -45,18 +43,26 @@ export interface SettingsRequestMessage extends BaseMessage {
   data: undefined;
 }
 
+/**
+ * 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`;
+}
+
 /**
  * The types of messages that an add-on can receive.
  *
  * @internal
  */
-export type ReceiveMessage =
-  | SettingsMessage
-  | SettingsRequestMessage;
+export type ReceiveMessage = SettingsMessage | SettingsRequestMessage;
 
 /**
  * The types of messages that an add-on can send.
  *
  * @internal
  */
-export type SendMessage = SettingsMessage;
+export type SendMessage = ReadyMessage | SettingsMessage;

src/react/hooks.ts

@@ -10,11 +10,7 @@ import { createContext, useContext, useEffect, useMemo, useState } from "react";
 
 import type { ReceiveMessage } from "../internal";
 
-import {
-  type Settings,
-  receiveMessage,
-  sendMessage
-} from "../base";
+import { type Settings, receiveMessage, sendMessage } from "../base";
 
 /**
  * The context for providing the window object to the hooks and components.