Refactor frontend API classes (#482)

* Mark functions as private

* Remove constructor side effects

* Use safer handler invocation

* Mark functions as private

* Mark fields as private

* Update BackendApiForwarder public API

2 files changed, 5 insertions, 4 deletions

diff --git a/ext/bg/js/backend-api-forwarder.js b/ext/bg/js/backend-api-forwarder.js
index 93db77d7..4ac12730 100644
--- a/ext/bg/js/backend-api-forwarder.js
+++ b/ext/bg/js/backend-api-forwarder.js
@@ -17,11 +17,11 @@
 
 
 class BackendApiForwarder {
-    constructor() {
-        chrome.runtime.onConnect.addListener(this.onConnect.bind(this));
+    prepare() {
+        chrome.runtime.onConnect.addListener(this._onConnect.bind(this));
     }
 
-    onConnect(port) {
+    _onConnect(port) {
         if (port.name !== 'backend-api-forwarder') { return; }
 
         let tabId;
diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index 8a8f00eb..2fce4be9 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -70,7 +70,8 @@ class Backend {
 
         this.popupWindow = null;
 
-        this.apiForwarder = new BackendApiForwarder();
+        const apiForwarder = new BackendApiForwarder();
+        apiForwarder.prepare();
 
         this.messageToken = yomichan.generateId(16);