diff --git a/index.html b/index.html
index 5f83fc4..9a95ffa 100644
--- a/index.html
+++ b/index.html
@@ -104,7 +104,7 @@
     <header class="py-0 block">
       <div id="topbar" class="mx-auto flex flex-wrap pl-2 py-1 flex-row items-center bg-background">
         <a class="flex title-font font-medium items-center mb-0">
-          <img id="topos-logo" src="topos_frog.svg" class="w-12 h-12 text-selection_foreground p-2 rounded-full bg-foreground" alt="Topos Frog Logo"/>
+          <img id="topos_logo" src="topos_frog.svg" class="w-12 h-12 text-selection_foreground p-2 rounded-full bg-foreground" alt="Topos Frog Logo"/>
          <input id="universe-viewer" class="hidden transparent xl:block ml-4 text-2xl bg-background text-brightwhite placeholder-brightwhite" id="renamer" type="text" placeholder="Topos">
         </a>
         <nav class="py-2 flex flex-wrap items-center text-base absolute right-0">
diff --git a/src/API/API.ts b/src/API/API.ts
index 76dbb48..c89b3cd 100644
--- a/src/API/API.ts
+++ b/src/API/API.ts
@@ -462,7 +462,7 @@ export class UserAPI {
      *
      * @param code - The code example to play (identifier)
      */
-    let current_universe = this.app.universes[this.app.selected_universe];
+    let current_universe = this.app.universes[this.app.selected_universe]!;
     this.app.exampleIsPlaying = true;
     if (!current_universe.example) {
       current_universe.example = {
@@ -525,7 +525,7 @@ export class UserAPI {
         for (const line of stackLines) {
           if (line.includes("<anonymous>")) {
             const match = line.match(/<anonymous>:(\d+):(\d+)/);
-            if (match)
+            if (match as RegExpMatchArray)
               return {
                 line: parseInt(match[1], 10),
                 column: parseInt(match[2], 10),
diff --git a/src/API/Counter.ts b/src/API/Counter.ts
index bf87c87..92f5f98 100644
--- a/src/API/Counter.ts
+++ b/src/API/Counter.ts
@@ -36,8 +36,8 @@ export const counter = (api: UserAPI) => (name: string | number, limit?: number,
 
 export const i = (app: Editor) => (n?: number) => {
   if (n !== undefined) {
-    app.universes[app.selected_universe].global.evaluations = n;
+    app.universes[app.selected_universe]!.global.evaluations = n;
     return app.universes[app.selected_universe];
   }
-  return app.universes[app.selected_universe].global.evaluations as number;
+  return app.universes[app.selected_universe]!.global.evaluations as number;
 };
diff --git a/src/API/Time/Transport.ts b/src/API/Time/Transport.ts
index 98f5c32..975aefe 100644
--- a/src/API/Time/Transport.ts
+++ b/src/API/Time/Transport.ts
@@ -43,7 +43,7 @@ export const bpb = (app: Editor) => (n?: number): number => {
   /**
    * Sets or returns the number of beats per bar.
    */
-  if (n === undefined) return app.clock.time_signature[0];
+  if (n === undefined) return app.clock.time_signature[0] || 4;
 
   if (n >= 1) {
     app.clock.time_signature[0] = n;
@@ -103,11 +103,11 @@ export const epulse = (app: Editor) => (): number => {
 };
 
 export const nominator = (app: Editor) => (): number => {
-  return app.clock.time_signature[0];
+  return app.clock.time_signature[0] || 4;
 };
 
 export const meter = (app: Editor) => (): number => {
-  return app.clock.time_signature[1];
+  return app.clock.time_signature[1] || 4;
 };
 
 export const denominator = meter;
diff --git a/src/DOM/DomElements.ts b/src/DOM/DomElements.ts
index e014f91..fe5feaf 100644
--- a/src/DOM/DomElements.ts
+++ b/src/DOM/DomElements.ts
@@ -1,19 +1,7 @@
 import { type Editor } from "../main";
 
-export type ElementMap = {
-  [key: string]:
-  | HTMLElement
-  | HTMLButtonElement
-  | HTMLDivElement
-  | HTMLInputElement
-  | HTMLSelectElement
-  | HTMLCanvasElement
-  | HTMLFormElement
-  | HTMLInputElement;
-};
-
 export const singleElements = {
-  topos_logo: "topos-logo",
+  logo: "topos_logo",
   fill_viewer: "fillviewer",
   load_universe_button: "load-universe-button",
   download_universe_button: "download-universes",
@@ -56,6 +44,20 @@ export const singleElements = {
   error_line: "error_line",
   hydra_canvas: "hydra-bg",
   feedback: "feedback",
+} as const;
+
+export type SingleElementsKeys = keyof typeof singleElements;
+
+export type ElementMap = {
+  [K in SingleElementsKeys]:
+  | HTMLElement
+  | HTMLButtonElement
+  | HTMLDivElement
+  | HTMLInputElement
+  | HTMLSelectElement
+  | HTMLCanvasElement
+  | HTMLFormElement
+  | HTMLInputElement;
 };
 
 export const buttonGroups = {
diff --git a/src/DOM/UILogic.ts b/src/DOM/UILogic.ts
index a096dbc..4b154d4 100644
--- a/src/DOM/UILogic.ts
+++ b/src/DOM/UILogic.ts
@@ -50,30 +50,30 @@ export const installInterfaceLogic = (app: Editor) => {
   const tabs = document.querySelectorAll('[id^="tab-"]');
   // Iterate over the tabs with an index
   for (let i = 0; i < tabs.length; i++) {
-    tabs[i].addEventListener("click", (event) => {
+    tabs[i]!.addEventListener("click", (event) => {
       // Updating the CSS accordingly
-      tabs[i].classList.add("bg-foreground");
-      tabs[i].classList.add("text-selection_foreground");
+      tabs[i]!.classList.add("bg-foreground");
+      tabs[i]!.classList.add("text-selection_foreground");
       for (let j = 0; j < tabs.length; j++) {
-        if (j != i) tabs[j].classList.remove("bg-foreground");
-        if (j != i) tabs[j].classList.remove("text-selection_foreground");
+        if (j != i) tabs[j]!.classList.remove("bg-foreground");
+        if (j != i) tabs[j]!.classList.remove("text-selection_foreground");
       }
       app.currentFile().candidate = app.view.state.doc.toString();
 
       let tab = event.target as HTMLElement;
       let tab_id = tab.id.split("-")[1];
-      app.local_index = parseInt(tab_id);
+      app.local_index = parseInt(tab_id!);
       app.updateEditorView();
     });
   }
 
-  app.interface.topos_logo.addEventListener("click", () => {
+  app.interface['logo'].addEventListener("click", () => {
     hideDocumentation();
     app.updateKnownUniversesView();
     openUniverseModal();
   });
 
-  app.buttonElements.play_buttons.forEach((button) => {
+  app.buttonElements['play_buttons']!.forEach((button) => {
     button.addEventListener("click", () => {
       if (app.isPlaying) {
         app.setButtonHighlighting("pause", true);
@@ -89,7 +89,7 @@ export const installInterfaceLogic = (app: Editor) => {
     });
   });
 
-  app.buttonElements.clear_buttons.forEach((button) => {
+  app.buttonElements['clear_buttons']!.forEach((button) => {
     button.addEventListener("click", () => {
       app.setButtonHighlighting("clear", true);
       if (confirm("Do you want to reset the current universe?")) {
@@ -239,7 +239,7 @@ export const installInterfaceLogic = (app: Editor) => {
     app.flashBackground("#404040", 200);
   });
 
-  app.buttonElements.stop_buttons.forEach((button) => {
+  app.buttonElements['stop_buttons']!.forEach((button) => {
     button.addEventListener("click", () => {
       app.setButtonHighlighting("stop", true);
       app.isPlaying = false;
@@ -516,7 +516,7 @@ export const installInterfaceLogic = (app: Editor) => {
     }
   });
 
-  tryEvaluate(app, app.universes[app.selected_universe.toString()].init);
+  tryEvaluate(app, app.universes[app.selected_universe.toString()]!.init);
 
   documentation_pages.forEach((e) => {
     let name = `docs_` + e;
diff --git a/src/DOM/Visuals/Blinkers.ts b/src/DOM/Visuals/Blinkers.ts
index 666bd2f..6e3b58b 100644
--- a/src/DOM/Visuals/Blinkers.ts
+++ b/src/DOM/Visuals/Blinkers.ts
@@ -38,7 +38,7 @@ export const blinkScript = (
 ) => {
   if (no !== undefined && no < 1 && no > 9) return;
   const blinkDuration =
-    (app.clock.bpm / 60 / app.clock.time_signature[1]) * 200;
+    (app.clock.bpm / 60 / app.clock.time_signature[1]!) * 200;
   // @ts-ignore
   const ctx = app.interface.feedback.getContext("2d");
 
diff --git a/src/DOM/Visuals/Oscilloscope.ts b/src/DOM/Visuals/Oscilloscope.ts
index e0be360..fe6aa02 100644
--- a/src/DOM/Visuals/Oscilloscope.ts
+++ b/src/DOM/Visuals/Oscilloscope.ts
@@ -71,7 +71,7 @@ export const runOscilloscope = (
 
     for (let i = 0; i < numBars; i++) {
       barHeight = Math.floor(
-        freqDataArray[Math.floor((i * freqDataArray.length) / numBars)] *
+        freqDataArray[Math.floor((i * freqDataArray.length) / numBars)]! *
           ((height / 256) * app.osc.size),
       );
 
@@ -165,9 +165,9 @@ export const runOscilloscope = (
     let startIndex = 0;
     for (let i = 1; i < dataArray.length; ++i) {
       let currentType = null;
-      if (dataArray[i] >= 0 && dataArray[i - 1] < 0) {
+      if (dataArray[i]! >= 0 && dataArray[i - 1]! < 0) {
         currentType = "negToPos";
-      } else if (dataArray[i] < 0 && dataArray[i - 1] >= 0) {
+      } else if (dataArray[i]! < 0 && dataArray[i - 1]! >= 0) {
         currentType = "posToNeg";
       }
 
@@ -187,8 +187,8 @@ export const runOscilloscope = (
       drawFrequencyScope(WIDTH, HEIGHT, OFFSET_HEIGHT, OFFSET_WIDTH);
     } else if (app.osc.mode === "3D") {
       for (let i = startIndex; i < dataArray.length; i += 2) {
-        const x = (dataArray[i] * WIDTH * app.osc.size) / 2 + WIDTH / 4;
-        const y = (dataArray[i + 1] * HEIGHT * app.osc.size) / 2 + HEIGHT / 4;
+        const x = (dataArray[i]! * WIDTH * app.osc.size) / 2 + WIDTH / 4;
+        const y = (dataArray[i + 1]! * HEIGHT * app.osc.size) / 2 + HEIGHT / 4;
         i === startIndex ? canvasCtx.moveTo(x, y) : canvasCtx.lineTo(x, y);
       }
     } else if (
@@ -199,7 +199,7 @@ export const runOscilloscope = (
       const yOffset = HEIGHT / 4;
       let x = 0;
       for (let i = startIndex; i < dataArray.length; i++) {
-        const v = dataArray[i] * 0.5 * HEIGHT * app.osc.size;
+        const v = dataArray[i]! * 0.5 * HEIGHT * app.osc.size;
         const y = v + yOffset;
         i === startIndex ? canvasCtx.moveTo(x, y) : canvasCtx.lineTo(x, y);
         x += sliceWidth;
@@ -210,7 +210,7 @@ export const runOscilloscope = (
       const xOffset = WIDTH / 4;
       let y = 0;
       for (let i = startIndex; i < dataArray.length; i++) {
-        const v = dataArray[i] * 0.5 * WIDTH * app.osc.size;
+        const v = dataArray[i]! * 0.5 * WIDTH * app.osc.size;
         const x = v + xOffset;
         i === startIndex ? canvasCtx.moveTo(x, y) : canvasCtx.lineTo(x, y);
         y += sliceHeight;
diff --git a/src/Docs/Documentation.ts b/src/Docs/Documentation.ts
index be65f5a..6d53fbd 100644
--- a/src/Docs/Documentation.ts
+++ b/src/Docs/Documentation.ts
@@ -249,7 +249,7 @@ export const updateDocumentationContent = (app: Editor, bindings: any) => {
 
   function _update_and_assign(callback: Function) {
     const converted_markdown = converter.makeHtml(
-      app.docs[app.currentDocumentationPane],
+      app.docs[app.currentDocumentationPane]!,
     );
     callback(converted_markdown)
   }
diff --git a/src/Docs/inlineHelp.ts b/src/Docs/inlineHelp.ts
index d0dd249..05ef559 100644
--- a/src/Docs/inlineHelp.ts
+++ b/src/Docs/inlineHelp.ts
@@ -940,7 +940,7 @@ const completionDatabase: CompletionDatabase = {
     description: "Noise amount in the signal (0-1)",
     example: "sound('triangle').noise(.25).out()",
   },
-};
+} as const;
 
 export const inlineHoveringTips = hoverTooltip(
   (view: any, pos: any, side: any) => {
@@ -962,8 +962,7 @@ export const inlineHoveringTips = hoverTooltip(
         ) {
           return { dom: document.createElement("div") };
         }
-        let completion =
-          completionDatabase[text.slice(start - from, end - from)] || {};
+        let completion = completionDatabase[text.slice(start - from, end - from)]!;
         let divContent = `
       <h1 class="text-brightwhite text-base pb-1">${completion.name} [<em class="text-white">${completion.category}</em>]</h1>
       <p class="text-base pl-4">${completion.description}</p>
@@ -986,13 +985,13 @@ export const toposCompletions = (context: CompletionContext) => {
       from: word.from,
       options: Object.keys(completionDatabase).map((key) => ({
         label: key,
-        type: completionDatabase[key].category,
+        type: completionDatabase[key]!.category,
         info: () => {
           let div = document.createElement("div");
           div.innerHTML = `
-      <h1 class="text-brightwhite text-base pb-1">${completionDatabase[key].name} [<em class="text-white">${completionDatabase[key].category}</em>]</h1>
-      <p class="text-base pl-4">${completionDatabase[key].description}</p>
-      <div class="overflow-hidden overflow-scroll rounded px-2 ml-4 mt-2 bg-neutral-800"><code class="text-sm">${completionDatabase[key].example}</code></div>
+      <h1 class="text-brightwhite text-base pb-1">${completionDatabase[key]!.name} [<em class="text-white">${completionDatabase[key]!.category}</em>]</h1>
+      <p class="text-base pl-4">${completionDatabase[key]!.description}</p>
+      <div class="overflow-hidden overflow-scroll rounded px-2 ml-4 mt-2 bg-neutral-800"><code class="text-sm">${completionDatabase[key]!.example}</code></div>
       `;
           div.classList.add("px-4", "py-2", "rounded-lg", "w-92");
           return div;
@@ -1000,6 +999,7 @@ export const toposCompletions = (context: CompletionContext) => {
       })),
     };
   }
+  return null
 };
 
 export const soundCompletions = (context: CompletionContext) => {
diff --git a/src/Editor/FileManagement.ts b/src/Editor/FileManagement.ts
index 915504f..cb327b5 100644
--- a/src/Editor/FileManagement.ts
+++ b/src/Editor/FileManagement.ts
@@ -179,7 +179,7 @@ export class AppSettings {
   }
 
   get_universe() {
-    this.universes.universe_name;
+    this.universes["universe_name"];
   }
 
   get data(): Settings {
@@ -356,7 +356,7 @@ export const loadUniverse = (
   // Updating the editor View to reflect the selected universe
   app.updateEditorView();
   // Evaluating the initialisation script for the selected universe
-  tryEvaluate(app, app.universes[app.selected_universe.toString()].init);
+  tryEvaluate(app, app.universes[app.selected_universe.toString()]!.init);
 };
 
 export const openUniverseModal = (): void => {
diff --git a/src/Evaluator.ts b/src/Evaluator.ts
index d2a55af..e56fd56 100644
--- a/src/Evaluator.ts
+++ b/src/Evaluator.ts
@@ -18,7 +18,7 @@ async function tryCatchWrapper(application: Editor, code: string): Promise<boole
     await new Function(`"use strict"; ${codeReplace(code)}`).call(application.api);
     return true;
   } catch (error) {
-    application.interface.error_line.innerHTML = error as string;
+    application.interface["error_line"].innerHTML = error as string;
     application.api._reportError(error as string);
     return false;
   }
@@ -89,7 +89,7 @@ export async function evaluate(application: Editor, code: File, timeout = 1000):
     ]);
     code.evaluations!++;
   } catch (error) {
-    application.interface.error_line.innerHTML = error as string;
+    application.interface["error_line"].innerHTML = error as string;
     console.error(error);
   }
 }
diff --git a/src/IO/SampleLoading.ts b/src/IO/SampleLoading.ts
index 4a52921..a21be03 100644
--- a/src/IO/SampleLoading.ts
+++ b/src/IO/SampleLoading.ts
@@ -8,7 +8,10 @@
 // @ts-ignore
 import { registerSound, onTriggerSample } from "superdough";
 
-export const isAudioFile = (filename: string) => ['wav', 'mp3'].includes(filename.split('.').slice(-1)[0]);
+export const isAudioFile = (filename: string) => {
+  const extension = filename.split('.').slice(-1)[0];
+  return extension !== undefined && ['wav', 'mp3'].includes(extension);
+};
 
 interface samplesDBConfig {
   dbName: string,
diff --git a/src/classes/ZPlayer.ts b/src/classes/ZPlayer.ts
index a8868a2..29d265e 100644
--- a/src/classes/ZPlayer.ts
+++ b/src/classes/ZPlayer.ts
@@ -30,7 +30,7 @@ export class Player extends AbstractEvent {
   constructor(
     input: string | number | Generator<number>,
     options: InputOptions,
-    public app: Editor,
+    app: Editor,
     zid: string = "",
     waitTime: number = 0,
   ) {
@@ -191,7 +191,7 @@ export class Player extends AbstractEvent {
     }
   }
 
-  sound(name?: string | string[] | SoundParams | SoundParams[]) {
+  public sound(name?: string | string[] | SoundParams | SoundParams[]) {
     if (this.areWeThereYet()) {
       this.checkCue();
       const event = this.next() as Pitch | Chord | ZRest;
@@ -252,7 +252,7 @@ export class Player extends AbstractEvent {
     }
   }
 
-  midi(value: number | undefined = undefined) {
+  public midi(value: number | undefined = undefined) {
     if (this.areWeThereYet()) {
       this.checkCue();
       const event = this.next() as Pitch | Chord | ZRest;
diff --git a/src/clock/Clock.ts b/src/clock/Clock.ts
index 5159714..3bf7647 100644
--- a/src/clock/Clock.ts
+++ b/src/clock/Clock.ts
@@ -82,7 +82,7 @@ export class Clock {
      * @returns The TimePosition object representing the converted ticks.
      */
 
-    const beatsPerBar = this.app.clock.time_signature[0];
+    const beatsPerBar = this.app.clock.time_signature[0]!;
     const ppqnPosition = ticks % this.app.clock.ppqn;
     const beatNumber = Math.floor(ticks / this.app.clock.ppqn);
     const barNumber = Math.floor(beatNumber / beatsPerBar);
@@ -116,7 +116,7 @@ export class Clock {
     /**
      * Returns the number of beats per bar.
      */
-    return this.time_signature[0];
+    return this.time_signature[0] || 4;
   }
 
   get beats_since_origin(): number {
diff --git a/src/extensions/ArrayExtensions.ts b/src/extensions/ArrayExtensions.ts
index 11c3355..d089862 100644
--- a/src/extensions/ArrayExtensions.ts
+++ b/src/extensions/ArrayExtensions.ts
@@ -47,8 +47,7 @@ export const makeArrayExtensions = (api: UserAPI) => {
     const screenWidth = window.innerWidth;
     const zoneWidth = screenWidth / this.length;
     const zoneIndex = Math.floor(mouse_position / zoneWidth);
-
-    return this[zoneIndex];
+    return this[zoneIndex]!;
   };
 
   Array.prototype.mouseY = function <T>(this: T[]): T {
@@ -56,8 +55,7 @@ export const makeArrayExtensions = (api: UserAPI) => {
     const screenHeight = window.innerHeight;
     const zoneHeight = screenHeight / this.length;
     const zoneIndex = Math.floor(mouse_position / zoneHeight);
-
-    return this[zoneIndex];
+    return this[zoneIndex]!;
   };
 
   Array.prototype.square = function(): number[] {
@@ -175,7 +173,7 @@ export const makeArrayExtensions = (api: UserAPI) => {
   Array.prototype.dur = function(...durations: number[]) {
     const timepos = api.app.clock.pulses_since_origin;
     const ppqn = api.ppqn();
-    const adjustedDurations: number[] = this.map(
+    const adjustedDurations = this.map(
       (_, index) => durations[index % durations.length],
     );
     const totalDurationInPulses = adjustedDurations.reduce(
@@ -183,7 +181,7 @@ export const makeArrayExtensions = (api: UserAPI) => {
       (acc, duration) => acc + duration * ppqn,
       0,
     );
-    const loopPosition = timepos % totalDurationInPulses;
+    const loopPosition = timepos % totalDurationInPulses!;
     let cumulativeDuration = 0;
     for (let i = 0; i < this.length; i++) {
       const valueDurationInPulses = (adjustedDurations[i] as any) * ppqn;
@@ -295,12 +293,12 @@ export const makeArrayExtensions = (api: UserAPI) => {
     let result = [];
     for (let i = 0; i < this.length; i++) {
       for (let j = 0; j < amount; j++) {
-        result.push(this[i]);
+        result.push(this[i] as T);
       }
     }
 
     this.length = 0;
-    this.push(...result);
+    this.push(...result as T[]);
     return this;
   };
 
@@ -322,15 +320,15 @@ export const makeArrayExtensions = (api: UserAPI) => {
       // If the index is even, repeat the element
       if (i % 2 === 0) {
         for (let j = 0; j < amount; j++) {
-          result.push(this[i]);
+          result.push(this[i] as T);
         }
       } else {
-        result.push(this[i]);
+        result.push(this[i] as T);
       }
     }
 
     this.length = 0;
-    this.push(...result);
+    this.push(...result as T[]);
     return this;
   };
 
@@ -355,10 +353,10 @@ export const makeArrayExtensions = (api: UserAPI) => {
       // If the index is odd, repeat the element
       if (i % 2 !== 0) {
         for (let j = 0; j < amount; j++) {
-          result.push(this[i]);
+          result.push(this[i] as T);
         }
       } else {
-        result.push(this[i]);
+        result.push(this[i] as T);
       }
     }
 
@@ -442,7 +440,7 @@ Array.prototype.scale = function(
   return this.map((value) => {
     const octaveShift = Math.floor(value / selected_scale.length) * 12;
     return (
-      selected_scale[mod(Math.floor(value), selected_scale.length)] +
+      selected_scale[mod(Math.floor(value), selected_scale.length)]! +
       base_note +
       octaveShift
     );
diff --git a/src/extensions/StringExtensions.ts b/src/extensions/StringExtensions.ts
index 1f7d585..714abcd 100644
--- a/src/extensions/StringExtensions.ts
+++ b/src/extensions/StringExtensions.ts
@@ -187,7 +187,7 @@ export class Speaker {
         utterance.pitch = this.options.pitch || 1;
         utterance.volume = this.options.volume || 1;
         if (this.options.voice) {
-          utterance.voice = synth.getVoices()[this.options.voice];
+          utterance.voice = synth.getVoices()[this.options.voice]!;
         }
         if (this.options.lang) {
           // Check if language has country code
diff --git a/src/main.ts b/src/main.ts
index a83d783..03ba582 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -69,7 +69,7 @@ export class Editor {
   show_error: boolean = false;
   currentThemeName: string = "Everblush";
   buttonElements: Record<string, HTMLButtonElement[]> = {};
-  interface: ElementMap = {};
+  interface!: ElementMap;
   blinkTimeouts: Record<number, number> = {};
   osc: OscilloscopeConfig = {
     enabled: false,
@@ -126,7 +126,6 @@ export class Editor {
     this.initializeElements();
     this.initializeButtonGroups();
     this.setCanvas(this.interface["feedback"] as HTMLCanvasElement);
-    // this.loadHydraSynthAsync();
 
     // ================================================================================
     // Loading the universe from local storage
@@ -356,29 +355,29 @@ export class Editor {
         this.local_index = 0;
         document.getElementById("editor")!.style.height = "calc(100% - 100px)";
         this.changeToLocalBuffer(this.local_index);
-        changeColor(this.interface.local_button);
+        changeColor(this.interface["local_button"]);
         break;
       case "global":
-        if (!this.interface.local_script_tabs.classList.contains("hidden")) {
-          this.interface.local_script_tabs.classList.add("hidden");
+        if (!this.interface["local_script_tabs"].classList.contains("hidden")) {
+          this.interface["local_script_tabs"].classList.add("hidden");
         }
         this.editor_mode = "global";
         document.getElementById("editor")!.style.height = "100%";
-        changeColor(this.interface.global_button);
+        changeColor(this.interface["global_button"]);
         break;
       case "init":
-        if (!this.interface.local_script_tabs.classList.contains("hidden")) {
-          this.interface.local_script_tabs.classList.add("hidden");
+        if (!this.interface["local_script_tabs"].classList.contains("hidden")) {
+          this.interface["local_script_tabs"].classList.add("hidden");
         }
         this.editor_mode = "init";
-        changeColor(this.interface.init_button);
+        changeColor(this.interface["init_button"]);
         break;
       case "notes":
-        if (!this.interface.local_script_tabs.classList.contains("hidden")) {
-          this.interface.local_script_tabs.classList.add("hidden");
+        if (!this.interface["local_script_tabs"].classList.contains("hidden")) {
+          this.interface["local_script_tabs"].classList.add("hidden");
         }
         this.editor_mode = "notes";
-        changeColor(this.interface.note_button);
+        changeColor(this.interface["note_button"]);
         break;
     }
 
@@ -441,19 +440,26 @@ export class Editor {
         selector = 3;
         break;
     }
-    document
-      .querySelectorAll(possible_selectors[selector])
-      .forEach((button) => {
-        if (highlight) button.children[0].classList.add("animate-pulse");
-      });
+    const selectorValue = possible_selectors[selector];
+    if (selectorValue) {
+      document
+        .querySelectorAll(selectorValue)
+        .forEach((button) => {
+          if (highlight && button.children[0]) button.children[0].classList.add("animate-pulse");
+        });
+    }
     // All other buttons must lose the highlighting
     document
       .querySelectorAll(
         possible_selectors.filter((_, index) => index != selector).join(","),
       )
       .forEach((button) => {
-        button.children[0].classList.remove("animate-pulse");
-        button.children[1].classList.remove("animate-pulse");
+        if (button.children[0]) {
+          button.children[0].classList.remove("animate-pulse");
+        }
+        if (button.children[1]) {
+          button.children[1].classList.remove("animate-pulse");
+        }
       });
   }
 
@@ -525,7 +531,7 @@ export class Editor {
 
   private initializeElements(): void {
     for (const [key, value] of Object.entries(singleElements)) {
-      this.interface[key] = document.getElementById(
+      this.interface[key as keyof ElementMap] = document.getElementById(
         value,
       ) as ElementMap[keyof ElementMap];
     }