diff --git a/src/content/options.js b/src/content/options.js
index fb2edd9..813191e 100644
--- a/src/content/options.js
+++ b/src/content/options.js
@@ -192,7 +192,6 @@ class Options {
       obj[i.dataset.id] = i.type === 'checkbox' ? i.checked : i.value.trim();
     });
 
-
     // --- check type: http | https | socks4 | socks5 | pac | direct
     switch (true) {
       // DIRECT
@@ -386,7 +385,7 @@ class WebRTC {
     // { "levelOfControl": "controllable_by_this_extension", "value": "default" }
     this.result ||= await browser.privacy.network.webRTCIPHandlingPolicy.get({});
     const def = this.result.value === 'default';
-    let value = def ? 'default_public_interface_only' : 'default';
+    const value = def ? 'default_public_interface_only' : 'default';
     this.result.value = value;
     this.webRTC.checked = def;                              // was default but now changed
     browser.privacy.network.webRTCIPHandlingPolicy.set({value});
@@ -522,7 +521,6 @@ class Proxies {
     pxy.querySelector('button[data-i18n^="export"]').addEventListener('click', () =>
       this.exportPattern(patternBox, elem[1].value.trim() || elem[3].value.trim()));
 
-
     // from add button
     if (!item) {
       this.proxyDiv.appendChild(pxy);                       // insert blank proxy
@@ -935,7 +933,7 @@ class ImportProxyList {
     const pram = {type, hostname, port, username, password};
 
     // prepare object, make parameter keys case-insensitive
-    for (let [key, value] of url.searchParams) {
+    for (const [key, value] of url.searchParams) {
       pram[key.toLowerCase()] = value;
     }
 
diff --git a/src/content/proxy.js b/src/content/proxy.js
index 4e73989..b8a3117 100644
--- a/src/content/proxy.js
+++ b/src/content/proxy.js
@@ -218,7 +218,7 @@ export class Proxy {
     // isInNet(host, "192.0.2.172", "255.255.255.255")
 
     const pacString =
-`function FindProxyForURL(url, host) {
+String.raw`function FindProxyForURL(url, host) {
   const data = ${JSON.stringify(data)};
   const passthrough = ${JSON.stringify(passthrough)};
   const net = ${JSON.stringify(net)};
@@ -257,7 +257,7 @@ export class Proxy {
     const url = this.getURL(activeTab[0].url);
     if (!url) { return; }
 
-    const pattern = '^' + url.origin.replaceAll('.', '\.') + '/';
+    const pattern = '^' + url.origin.replaceAll('.', '\\.') + '/';
     const pat = {
       active: true,
       pattern,
@@ -287,7 +287,7 @@ export class Proxy {
     if (arr.includes(pattern)) { return; }                  // already added
 
     arr.push(pattern);
-    pref.passthrough = [...new Set(arr)].join(separator);   // remove duplicates
+    pref.passthrough = [...new Set(arr)].join(separator).trim(); // remove duplicates
 
     browser.storage.local.set({passthrough: pref.passthrough});
     this.set(pref);                                         // update Proxy
diff --git a/src/content/sync.js b/src/content/sync.js
index b5341d0..f099ef9 100644
--- a/src/content/sync.js
+++ b/src/content/sync.js
@@ -11,14 +11,14 @@ export class Sync {
 
   static async onChanged(changes) {
     // no newValue on storage.local.clear()
-    if (!Object.values(changes)[0]?.hasOwnProperty('newValue')) { return; }
+    if (!Object.hasOwn(Object.values(changes)[0] || {}, 'newValue')) { return; }
 
     const pref = await browser.storage.local.get();
     if (!pref.sync) { return; }
 
     // convert object to array + filter null newValue (deleted) + map to newValue
     const data = Object.values(changes)
-      .filter(i => i.newValue?.hasOwnProperty('hostname') || i.newValue?.hasOwnProperty('pac'))
+      .filter(i => Object.hasOwn(i.newValue || {}, 'hostname'))
       .map(i => i.newValue);
 
     const obj = {};