diff --git a/modules/names-generator.js b/modules/names-generator.js
index 3646a0c3..68c2a141 100644
--- a/modules/names-generator.js
+++ b/modules/names-generator.js
@@ -1,4 +1,5 @@
 import {last} from "/src/utils/arrayUtils";
+import {locked} from "/src/scripts/options/lock";
 
 window.Names = (function () {
   let chains = [];
diff --git a/modules/ui/general.js b/modules/ui/general.js
index 0fbff4e5..c7bc47dd 100644
--- a/modules/ui/general.js
+++ b/modules/ui/general.js
@@ -414,57 +414,6 @@ function highlightEmblemElement(type, el) {
     .remove();
 }
 
-// assign lock behavior
-document.querySelectorAll("[data-locked]").forEach(function (e) {
-  e.addEventListener("mouseover", function (event) {
-    if (this.className === "icon-lock")
-      tip("Click to unlock the option and allow it to be randomized on new map generation");
-    else tip("Click to lock the option and always use the current value on new map generation");
-    event.stopPropagation();
-  });
-
-  e.addEventListener("click", function () {
-    const id = this.id.slice(5);
-    if (this.className === "icon-lock") unlock(id);
-    else lock(id);
-  });
-});
-
-// lock option
-export function lock(id) {
-  const input = document.querySelector('[data-stored="' + id + '"]');
-  if (input) store(id, input.value);
-  const el = document.getElementById("lock_" + id);
-  if (!el) return;
-  el.dataset.locked = 1;
-  el.className = "icon-lock";
-}
-
-// unlock option
-function unlock(id) {
-  localStorage.removeItem(id);
-  const el = document.getElementById("lock_" + id);
-  if (!el) return;
-  el.dataset.locked = 0;
-  el.className = "icon-lock-open";
-}
-
-// check if option is locked
-export function locked(id) {
-  const lockEl = document.getElementById("lock_" + id);
-  return lockEl.dataset.locked == 1;
-}
-
-// return key value stored in localStorage or null
-export function stored(key) {
-  return localStorage.getItem(key) || null;
-}
-
-// store key value in localStorage
-function store(key, value) {
-  return localStorage.setItem(key, value);
-}
-
 // assign skeaker behaviour
 Array.from(document.getElementsByClassName("speaker")).forEach(el => {
   const input = el.previousElementSibling;
diff --git a/modules/ui/options.js b/modules/ui/options.js
index 67f90a21..88319c86 100644
--- a/modules/ui/options.js
+++ b/modules/ui/options.js
@@ -1,6 +1,7 @@
-import {stored, lock, locked, applyOption} from "./general";
+import {applyOption} from "./general";
 import {last} from "/src/utils/arrayUtils";
-import {byId} from "/src/utils/shorthands";
+import {byId, stored} from "/src/utils/shorthands";
+import {lock, locked} from "/src/scripts/options/lock";
 
 $("#optionsContainer").draggable({handle: ".drag-trigger", snap: "svg", snapMode: "both"});
 $("#exitCustomization").draggable({handle: "div"});
diff --git a/src/main.ts b/src/main.ts
index 98d4745d..dcdc17cf 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,7 +1,7 @@
 // Azgaar (azgaar.fmg@yandex.com). Minsk, 2017-2022. MIT License
 // https://github.com/Azgaar/Fantasy-Map-Generator
 
-import {PRODUCTION, UINT16_MAX} from "./constants";
+import {UINT16_MAX} from "./constants";
 import {INFO, TIME, WARN, ERROR} from "./config/logging";
 import {
   shouldRegenerateGrid,
@@ -15,32 +15,17 @@ import {createTypedArray} from "./utils/arrayUtils";
 import {drawRivers, drawStates, drawBorders} from "../modules/ui/layers";
 import {invokeActiveZooming} from "../modules/activeZooming";
 import {applyStoredOptions, applyMapSize, randomizeOptions} from "../modules/ui/options";
-import {locked} from "../modules/ui/general";
+import {locked} from "./scripts/options/lock";
 import {Rulers, Ruler, drawScaleBar} from "./modules/measurers";
 import {byId} from "./utils/shorthands";
+import {addGlobalListeners} from "./scripts/listeners";
+
+addGlobalListeners();
 
 window.fmg = {
   modules: {}
 };
 
-if (PRODUCTION && "serviceWorker" in navigator) {
-  window.addEventListener("load", () => {
-    navigator.serviceWorker.register("../sw.js").catch(err => {
-      console.error("ServiceWorker registration failed: ", err);
-    });
-  });
-
-  window.addEventListener(
-    "beforeinstallprompt",
-    async event => {
-      event.preventDefault();
-      const Installation = await import("../modules/dynamic/installation.js");
-      Installation.init(event);
-    },
-    {once: true}
-  );
-}
-
 // default options
 options = {
   pinNotes: false,
diff --git a/src/scripts/listeners.ts b/src/scripts/listeners.ts
new file mode 100644
index 00000000..c60c5b7a
--- /dev/null
+++ b/src/scripts/listeners.ts
@@ -0,0 +1,29 @@
+import {PRODUCTION} from "../constants";
+import {assignLockBehavior} from "./options/lock";
+
+export function addGlobalListeners() {
+  PRODUCTION && registerServiceWorker();
+  PRODUCTION && addInstallationPrompt();
+  assignLockBehavior();
+}
+
+function registerServiceWorker() {
+  "serviceWorker" in navigator &&
+    window.addEventListener("load", () => {
+      navigator.serviceWorker.register("../../sw.js").catch(err => {
+        console.error("ServiceWorker registration failed: ", err);
+      });
+    });
+}
+
+function addInstallationPrompt() {
+  window.addEventListener(
+    "beforeinstallprompt",
+    async event => {
+      event.preventDefault();
+      const Installation = await import("../../modules/dynamic/installation.js");
+      Installation.init(event);
+    },
+    {once: true}
+  );
+}
diff --git a/src/scripts/options/lock.ts b/src/scripts/options/lock.ts
new file mode 100644
index 00000000..cd5ccb63
--- /dev/null
+++ b/src/scripts/options/lock.ts
@@ -0,0 +1,56 @@
+import {store} from "../../utils/shorthands";
+
+export function assignLockBehavior() {
+  const $lockable = document.querySelectorAll("[data-locked]");
+  $lockable.forEach($lockableEl => {
+    $lockableEl.addEventListener("mouseover", showTooltip);
+    $lockableEl.on("click", toggleLock);
+  });
+}
+
+function toggleLock(this: Element) {
+  const id = this.id.slice(5);
+  const isLocked = this.className === "icon-lock";
+  const toggle = isLocked ? unlock : lock;
+  toggle(id);
+}
+
+const lockMessage = "Click to lock the option and always use the current value on new map generation";
+const unlockMessage = "Click to unlock the option and allow it to be randomized on new map generation";
+
+function showTooltip(this: Element, event: Event) {
+  event.stopPropagation();
+  const isLocked = this.className === "icon-lock";
+  const message = isLocked ? unlockMessage : lockMessage;
+  tip(message);
+}
+
+// lock option from regeneration on page refresh
+export function lock(id: string) {
+  const $input = document.querySelector('[data-stored="' + id + '"]');
+  if ($input && $input instanceof HTMLInputElement === false) {
+    store(id, ($input as HTMLInputElement).value);
+  }
+
+  const $lock = document.getElementById("lock_" + id);
+  if ($lock) {
+    $lock.dataset.locked = "1";
+    $lock.className = "icon-lock";
+  }
+}
+
+// unlock option
+function unlock(id: string) {
+  localStorage.removeItem(id);
+  const $lock = document.getElementById("lock_" + id);
+  if ($lock) {
+    $lock.dataset.locked = "0";
+    $lock.className = "icon-lock-open";
+  }
+}
+
+// check if option is locked
+export function locked(id: string) {
+  const $lock = document.getElementById("lock_" + id);
+  return Boolean($lock && $lock.dataset.locked === "1");
+}
diff --git a/src/utils/shorthands.ts b/src/utils/shorthands.ts
index 9a45d053..ee5bd5ab 100644
--- a/src/utils/shorthands.ts
+++ b/src/utils/shorthands.ts
@@ -7,3 +7,11 @@ Node.prototype.on = function (name, fn, options) {
 Node.prototype.off = function (name, fn) {
   this.removeEventListener(name, fn);
 };
+
+export function stored(key: string) {
+  return localStorage.getItem(key) || null;
+}
+
+export function store(key: string, value: string) {
+  return localStorage.setItem(key, value);
+}
diff --git a/utils/languageUtils.js b/utils/languageUtils.js
index 87f5d67d..3b0c580e 100644
--- a/utils/languageUtils.js
+++ b/utils/languageUtils.js
@@ -8,7 +8,7 @@ function vowel(c) {
 
 // remove vowels from the end of the string
 function trimVowels(string, minLength = 3) {
-  while (string.length > minLength && vowel(last(string))) {
+  while (string.length > minLength && vowel(string.at(-1))) {
     string = string.slice(0, -1);
   }
   return string;