Require initialization to set up listeners

src/host/host.js

@@ -1,9 +1,8 @@
+let initialized = false;
+
 const allowedFrames = new Map();
 const registeredPlugins = new Map();
 
-window.addEventListener('message', e => handleContextRequestMessage(e));
-document.addEventListener('lms-context-request', e => handleContextRequestEvent(e));
-
 function handleContextRequest(type, options, subscribe) {
 	const plugin = registeredPlugins.get(type);
 	if (!plugin) {
@@ -66,7 +65,20 @@ function sendChangeEvent(type, changedValues) {
 	});
 }
 
+export function initialize() {
+	if (initialized) return;
+
+	window.addEventListener('message', handleContextRequestMessage);
+	document.addEventListener('lms-context-request', handleContextRequestEvent);
+
+	initialized = true;
+}
+
 export function allowFrame(frame, origin) {
+	if (!initialized) {
+		throw new Error(`lms-context-provider: Can't register frame with id ${frame.id}. Context provider host has not been initialized.`);
+	}
+
 	if (allowedFrames.has(frame)) {
 		throw new Error(`lms-context-provider: A frame with id ${frame.id} has already been registered with this host.`);
 	}
@@ -75,6 +87,10 @@ export function allowFrame(frame, origin) {
 }
 
 export function registerPlugin(name, tryGetCallback, subscriptionCallback) {
+	if (!initialized) {
+		throw new Error(`lms-context-provider: Can't register plugin with name ${name}. Context provider host has not been initialized.`);
+	}
+
 	if (registeredPlugins.has(name)) {
 		throw new Error(`lms-context-provider: A plugin with name ${name} has already been registered with this host.`);
 	}