Add Offscreen.prepare for constructor side effects (#402)

2 files changed, 9 insertions, 6 deletions

diff --git a/ext/js/background/offscreen-main.js b/ext/js/background/offscreen-main.js
index f85908bd..aac5b8f2 100644
--- a/ext/js/background/offscreen-main.js
+++ b/ext/js/background/offscreen-main.js
@@ -19,8 +19,9 @@
 import {Offscreen} from './offscreen.js';
 
 /** Entry point. */
-async function main() {
-    new Offscreen();
+function main() {
+    const offscreen = new Offscreen();
+    offscreen.prepare();
 }
 
-await main();
+main();
diff --git a/ext/js/background/offscreen.js b/ext/js/background/offscreen.js
index bcbcda6b..d1cf3384 100644
--- a/ext/js/background/offscreen.js
+++ b/ext/js/background/offscreen.js
@@ -68,13 +68,15 @@ export class Offscreen {
         ]));
         /* eslint-enable no-multi-spaces */
 
-        const onMessage = this._onMessage.bind(this);
-        chrome.runtime.onMessage.addListener(onMessage);
-
         /** @type {?Promise<void>} */
         this._prepareDatabasePromise = null;
     }
 
+    /** */
+    prepare() {
+        chrome.runtime.onMessage.addListener(this._onMessage.bind(this));
+    }
+
     /** @type {import('offscreen').MessageHandler<'clipboardGetTextOffscreen', true>} */
     async _getTextHandler({useRichText}) {
         return await this._clipboardReader.getText(useRichText);