Make background script of context-menu-copy-link-with-types non-persistent? (#501)

* Made background script of context-menu-copy-link-with-types non-persistent. Now clearing errors that could result from background.js context menu creation happening more than once.

* Suggestions from code review

* Syntax error and formatting

* Added note about () => void browser.runtime.lastError

* Feedback suggestion

Co-authored-by: Rob Wu <rob@robwu.nl>

---------

Co-authored-by: rebloor <git@sherpa.co.nz>
Co-authored-by: Rob Wu <rob@robwu.nl>

context-menu-copy-link-with-types/background.js

@@ -1,8 +1,16 @@
+// Callback reads runtime.lastError to prevent an unchecked error from being 
+// logged when the extension attempt to register the already-registered menu 
+// again. Menu registrations in event pages persist across extension restarts.
 browser.contextMenus.create({
-    id: "copy-link-to-clipboard",
-    title: "Copy link to clipboard",
-    contexts: ["link"],
-});
+        id: "copy-link-to-clipboard",
+        title: "Copy link to clipboard",
+        contexts: ["link"],
+    },
+    // See https://extensionworkshop.com/documentation/develop/manifest-v3-migration-guide/#event-pages-and-backward-compatibility
+    // for information on the purpose of this error capture.
+    () => void browser.runtime.lastError,
+);
+
 browser.contextMenus.onClicked.addListener((info, tab) => {
     if (info.menuItemId === "copy-link-to-clipboard") {
         // Examples: text and HTML to be copied.

context-menu-copy-link-with-types/manifest.json

@@ -8,7 +8,8 @@
     "background": {
         "scripts": [
             "background.js"
-        ]
+        ],
+        "persistent": false
     },
 
     "permissions": [