temporary listener abstraction

ext/fg/js/frame-offset-forwarder.js

@@ -44,17 +44,14 @@ class FrameOffsetForwarder {
     async applyOffset(x, y) {
         const uniqueId = yomichan.generateId(16);
 
-        let frameOffsetResolve = null;
+        const frameOffsetPromise = yomichan.getTemporaryListenerResult(
-        const frameOffsetPromise = new Promise((resolve) => (frameOffsetResolve = resolve));
+            chrome.runtime.onMessage,
-
+            ({action, params}, {resolve}) => {
-        const runtimeMessageCallback = ({action, params}, sender, callback) => {
                 if (action === 'frameOffset' && isObject(params) && params.uniqueId === uniqueId) {
-                chrome.runtime.onMessage.removeListener(runtimeMessageCallback);
+                    resolve(params);
-                callback();
-                frameOffsetResolve(params);
                 }
-        };
+            }
-        chrome.runtime.onMessage.addListener(runtimeMessageCallback);
+        );
 
         window.parent.postMessage({
             action: 'getFrameOffset',

ext/fg/js/frontend-initialize.js

@@ -32,19 +32,15 @@ async function main() {
 
     let popup;
     if (!proxy && (window !== window.parent)) {
-        let rootPopupInformationResolve;
+        const rootPopupInformationPromise = yomichan.getTemporaryListenerResult(
-        const rootPopupInformationPromise = new Promise((resolve) => (rootPopupInformationResolve = resolve));
+            chrome.runtime.onMessage,
-
+            ({action, params}, {resolve}) => {
-        const runtimeMessageCallback = ({action, params}, sender, callback) => {
                 if (action === 'rootPopupInformation') {
-                chrome.runtime.onMessage.removeListener(runtimeMessageCallback);
+                    resolve(params);
-                callback();
-                rootPopupInformationResolve(params);
                 }
-        };
+            }
-        chrome.runtime.onMessage.addListener(runtimeMessageCallback);
+        );
         apiForward('rootPopupRequestInformationBroadcast');
-
         const {popupId, frameId} = await rootPopupInformationPromise;
 
         const frameOffsetForwarder = new FrameOffsetForwarder();

ext/mixed/js/core.js

@@ -312,6 +312,42 @@ const yomichan = (() => {
             this.trigger('orphaned', {error});
         }
 
+        getTemporaryListenerResult(eventHandler, userCallback, timeout=30000) {
+            let resolved = false;
+            let resolve;
+            let reject;
+            const listenerPromise = new Promise((_resolve, _reject) => {
+                resolve = _resolve;
+                reject = _reject;
+            });
+
+            if (eventHandler === chrome.runtime.onMessage) {
+                const runtimeMessageCallback = ({action, params}, sender, sendResponse) => {
+                    const cleanupResolve = (value) => {
+                        resolved = true;
+                        eventHandler.removeListener(runtimeMessageCallback);
+                        sendResponse();
+                        resolve(value);
+                    };
+
+                    setTimeout(() => {
+                        if (!resolved) {
+                            reject(new Error(`Listener timed out in ${timeout} ms`));
+                            eventHandler.removeListener(runtimeMessageCallback);
+                        }
+                    }, timeout);
+
+                    userCallback({action, params}, {resolve: cleanupResolve, sender});
+                };
+
+                eventHandler.addListener(runtimeMessageCallback);
+            } else {
+                throw new Error('Event handler type not supported');
+            }
+
+            return listenerPromise;
+        }
+
         // Private
 
         _onMessage({action, params}, sender, callback) {