4 files changed, 11 insertions, 12 deletions
diff --git a/ext/fg/js/frontend-api-receiver.js b/ext/fg/js/frontend-api-receiver.js
index 687e5c3c..fbfb3ab0 100644
--- a/ext/fg/js/frontend-api-receiver.js
+++ b/ext/fg/js/frontend-api-receiver.js
@@ -46,9 +46,8 @@ class FrontendApiReceiver {
             result => {
                 this.sendResult(port, id, senderId, {result});
             },
-            e => {
-                const error = typeof e.toString === 'function' ? e.toString() : e;
-                this.sendResult(port, id, senderId, {error});
+            error => {
+                this.sendResult(port, id, senderId, {error: errorToJson(error)});
             });
     }
 
diff --git a/ext/fg/js/frontend-api-sender.js b/ext/fg/js/frontend-api-sender.js
index 2e037e62..c6eeaeb2 100644
--- a/ext/fg/js/frontend-api-sender.js
+++ b/ext/fg/js/frontend-api-sender.js
@@ -31,7 +31,7 @@ class FrontendApiSender {
 
     invoke(action, params, target) {
         if (this.disconnected) {
-            return Promise.reject('Disconnected');
+            return Promise.reject(new Error('Disconnected'));
         }
 
         if (this.port === null) {
@@ -110,8 +110,8 @@ class FrontendApiSender {
         clearTimeout(info.timer);
         info.timer = null;
 
-        if (typeof data.error === 'string') {
-            info.reject(data.error);
+        if (typeof data.error !== 'undefined') {
+            info.reject(jsonToError(data.error));
         } else {
             info.resolve(data.result);
         }
@@ -122,7 +122,7 @@ class FrontendApiSender {
         const info = this.callbacks[id];
         delete this.callbacks[id];
         info.timer = null;
-        info.reject(reason);
+        info.reject(new Error(reason));
     }
 
     static generateId(length) {
diff --git a/ext/fg/js/popup-proxy.js b/ext/fg/js/popup-proxy.js
index 99b28549..efbd28b2 100644
--- a/ext/fg/js/popup-proxy.js
+++ b/ext/fg/js/popup-proxy.js
@@ -98,7 +98,7 @@ class PopupProxy {
 
     invokeHostApi(action, params={}) {
         if (typeof this.parentFrameId !== 'number') {
-            return Promise.reject('Invalid frame');
+            return Promise.reject(new Error('Invalid frame'));
         }
         return this.apiSender.invoke(action, params, `popup-proxy-host#${this.parentFrameId}`);
     }
diff --git a/ext/fg/js/util.js b/ext/fg/js/util.js
index dc99274e..9a7968a7 100644
--- a/ext/fg/js/util.js
+++ b/ext/fg/js/util.js
@@ -30,19 +30,19 @@ function utilInvoke(action, params={}) {
             chrome.runtime.sendMessage(data, (response) => {
                 utilCheckLastError(chrome.runtime.lastError);
                 if (response !== null && typeof response === 'object') {
-                    if (response.error) {
-                        reject(response.error);
+                    if (typeof response.error !== 'undefined') {
+                        reject(jsonToError(response.error));
                     } else {
                         resolve(response.result);
                     }
                 } else {
                     const message = response === null ? 'Unexpected null response' : `Unexpected response of type ${typeof response}`;
-                    reject(`${message} (${JSON.stringify(data)})`);
+                    reject(new Error(`${message} (${JSON.stringify(data)})`));
                 }
             });
         } catch (e) {
             window.yomichan_orphaned = true;
-            reject(e.message);
+            reject(e);
         }
     });
 }