diff --git a/src/Consts.ts b/src/Consts.ts
index 2eb0adf..cec749d 100644
--- a/src/Consts.ts
+++ b/src/Consts.ts
@@ -44,12 +44,12 @@ interface SessionJSON {
   };
 }
 
-interface Session {
+type Session = {
   csrfToken: string;
   token: string;
   cookieSet: string;
   sessionJSON: SessionJSON;
-}
+} | undefined;
 
 const UserAgent = "Mozilla/5.0";
 
diff --git a/src/ScratchSession.ts b/src/ScratchSession.ts
index 211bfe2..da64b77 100644
--- a/src/ScratchSession.ts
+++ b/src/ScratchSession.ts
@@ -59,11 +59,13 @@ type Message = PartialMessage & ({
  * Manages a Scratch session.
  */
 class ScratchSession {
-  username: string;
-  csrfToken: string;
-  token: string;
-  cookieSet: string;
-  sessionJSON: SessionJSON;
+  auth?: {
+    username: string;
+    csrfToken: string;
+    token: string;
+    cookieSet: string;
+    sessionJSON: SessionJSON;
+  }
 
   /**
    * Sets up the ScratchSession to use authenticated functions.
@@ -71,7 +73,6 @@ class ScratchSession {
    * @param pass The password of the user you want to log in to.
    */
   async init(user: string, pass: string) {
-    this.username = user;
     // a lot of this code is taken from
     // https://github.com/CubeyTheCube/scratchclient/blob/main/scratchclient/ScratchSession.py
     // thanks!
@@ -94,20 +95,22 @@ class ScratchSession {
       throw new Error("Login failed.");
     }
 
-    this.csrfToken = /scratchcsrftoken=(.*?);/gm.exec(
-      loginReq.headers.get("set-cookie")
-    )[1];
-    this.token = /"(.*)"/gm.exec(loginReq.headers.get("set-cookie"))[1];
-    this.cookieSet =
+    const setCookie = loginReq.headers.get("set-cookie");
+    if(!setCookie) throw Error("Something went wrong");
+    const csrfToken = /scratchcsrftoken=(.*?);/gm.exec(
+      setCookie
+    )![1];
+    const token = /"(.*)"/gm.exec(setCookie)![1];
+    const cookieSet =
       "scratchcsrftoken=" +
-      this.csrfToken +
+      csrfToken +
       ";scratchlanguage=en;scratchsessionsid=" +
-      this.token +
+      token +
       ";";
     const sessionFetch = await fetch("https://scratch.mit.edu/session", {
       method: "GET",
       headers: {
-        Cookie: this.cookieSet,
+        Cookie: cookieSet,
         "User-Agent": UserAgent,
         Referer: "https://scratch.mit.edu/",
         Host: "scratch.mit.edu",
@@ -118,7 +121,14 @@ class ScratchSession {
         "Accept-Encoding": "gzip, deflate, br"
       }
     });
-    this.sessionJSON = (await sessionFetch.json()) as SessionJSON;
+    const sessionJSON = (await sessionFetch.json()) as SessionJSON;
+    this.auth = {
+      username: user,
+      csrfToken,
+      token,
+      cookieSet,
+      sessionJSON
+    }
   }
 
   /**
@@ -131,6 +141,7 @@ class ScratchSession {
    * await session.uploadToAssets(fs.readFileSync("photo.png"), "png"); // returns URL to image
    */
   async uploadToAssets(buffer: Buffer, fileExtension: string) {
+    if(!this.auth) throw Error("You must be logged in to use this");
     const md5hash = createHash("md5").update(buffer).digest("hex");
     const upload = await fetch(
       `https://assets.scratch.mit.edu/${md5hash}.${fileExtension}`,
@@ -138,7 +149,7 @@ class ScratchSession {
         method: "POST",
         body: buffer,
         headers: {
-          Cookie: this.cookieSet,
+          Cookie: this.auth.cookieSet,
           "User-Agent": UserAgent,
           Referer: "https://scratch.mit.edu/",
           Host: "assets.scratch.mit.edu",
@@ -210,11 +221,12 @@ class ScratchSession {
    * @param offset The offset of messages
    */
   async getMessages(limit: number = 40, offset: number = 0) {
-    const request = await fetch(`https://api.scratch.mit.edu/users/${this.username}/messages?limit=${limit}&offset=${offset}`, {
+    if(!this.auth) throw Error("You must be logged in to use this");
+    const request = await fetch(`https://api.scratch.mit.edu/users/${this.auth.username}/messages?limit=${limit}&offset=${offset}`, {
       headers: {
         Origin: "https://scratch.mit.edu",
         Referer: "https://scratch.mit.edu/",
-        "X-Token": this.sessionJSON.user.token
+        "X-Token": this.auth.sessionJSON.user.token
       }
     });
     if(!request.ok) throw Error(`Request failed with status ${request.status}`);
@@ -225,14 +237,14 @@ class ScratchSession {
    * Logs out of Scratch.
    */
   async logout() {
-    if (!this.csrfToken || !this.token) return;
+    if(!this.auth) throw Error("You must be logged in to use this");
     const logoutFetch = await fetch(
       "https://scratch.mit.edu/accounts/logout/",
       {
         method: "POST",
-        body: `csrfmiddlewaretoken=${this.csrfToken}`,
+        body: `csrfmiddlewaretoken=${this.auth.csrfToken}`,
         headers: {
-          Cookie: this.cookieSet,
+          Cookie: this.auth.cookieSet,
           "User-Agent": UserAgent,
           accept: "application/json",
           Referer: "https://scratch.mit.edu/",
@@ -246,7 +258,8 @@ class ScratchSession {
     );
     if (!logoutFetch.ok) {
       throw new Error(`Error in logging out. ${logoutFetch.status}`);
-    }
+    };
+    this.auth = undefined;
   }
 }
 
diff --git a/src/classes/CloudConnection.ts b/src/classes/CloudConnection.ts
index 893aa19..fc1a751 100644
--- a/src/classes/CloudConnection.ts
+++ b/src/classes/CloudConnection.ts
@@ -13,8 +13,7 @@ import events from "node:events";
 class CloudConnection extends events.EventEmitter {
   id: number;
   session: Session;
-  server: string;
-  connection: WebSocket;
+  connection!: WebSocket;
   open: boolean = false;
   queue: Array<{
     user: string;
@@ -29,11 +28,11 @@ class CloudConnection extends events.EventEmitter {
     super();
     this.id = id;
     this.session = session;
-
     this.connect();
   }
 
   private connect() {
+    if(!this.session) throw Error("You need to be logged in")
     this.open = false;
     this.connection = new WebSocket("wss://clouddata.scratch.mit.edu", {
       headers: {
@@ -52,6 +51,7 @@ class CloudConnection extends events.EventEmitter {
       }
     });
     this.connection.on("open", () => {
+      if(!this.session) throw Error("You need to be logged in")
       this.open = true;
       this.send({
         method: "handshake",
@@ -90,6 +90,7 @@ class CloudConnection extends events.EventEmitter {
    * @param value The value to set the variable to.
    */
   setVariable(variable: string, value: number | string) {
+    if(!this.session) throw Error("You need to be logged in")
     const varname = variable.startsWith("☁ ")
       ? variable.substring(2)
       : variable;
@@ -116,9 +117,9 @@ class CloudConnection extends events.EventEmitter {
   /**
    * Gets a cloud variable.
    * @param variable The variable name to get.
-   * @returns {string} The value of the variable in string format.
+   * @returns The value of the variable in string format if it exists.
    */
-  getVariable(variable: string): string {
+  getVariable(variable: string) {
     const varname = variable.startsWith("☁ ")
       ? variable.substring(2)
       : variable;
diff --git a/src/classes/Profile.ts b/src/classes/Profile.ts
index 26f1299..76b002b 100644
--- a/src/classes/Profile.ts
+++ b/src/classes/Profile.ts
@@ -1,5 +1,6 @@
 import { Session, UserAgent } from "../Consts";
 import { parse } from "node-html-parser";
+import ScratchSession from "../ScratchSession";
 
 interface UserAPIResponse {
   id: number;
@@ -46,9 +47,9 @@ interface ProfileComment {
 class Profile {
   user: string;
   session: Session;
-  constructor(session: Session, username: string) {
+  constructor(session: ScratchSession, username: string) {
     this.user = username;
-    this.session = session;
+    this.session = session.auth;
   }
 
   /**
@@ -58,7 +59,7 @@ class Profile {
    */
   async getStatus() {
     const dom = parse(await this.getUserHTML());
-    return dom.querySelector(".group").innerHTML.trim() as
+    return dom.querySelector(".group")!.innerHTML.trim() as
       | "Scratcher"
       | "New Scratcher"
       | "Scratch Team";
@@ -68,6 +69,7 @@ class Profile {
    * Follow the user
    */
   async follow() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://scratch.mit.edu/site-api/users/followers/${this.user}/add/?usernames=${this.session.sessionJSON.user.username}`,
       {
@@ -92,6 +94,7 @@ class Profile {
    * Unfollow the user
    */
   async unfollow() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://scratch.mit.edu/site-api/users/followers/${this.user}/remove/?usernames=${this.session.sessionJSON.user.username}`,
       {
@@ -117,6 +120,7 @@ class Profile {
    * @param id The comment ID, for example 12345, *not* comment-12345.
    */
   async deleteComment(id: string | number) {
+    if(!this.session) throw Error("You need to be logged in")
     const delFetch = await fetch(
       `https://scratch.mit.edu/site-api/comments/user/${this.user}/del/`,
       {
@@ -199,38 +203,38 @@ class Profile {
     for (let elID in items) {
       const element = items[elID];
       if (typeof element == "function") break;
-      const commentID = element.querySelector(".comment").id;
+      const commentID = element.querySelector(".comment")!.id;
       const commentPoster = element
-        .querySelector(".comment")
+        .querySelector(".comment")!
         .getElementsByTagName("a")[0]
-        .getAttribute("data-comment-user");
+        .getAttribute("data-comment-user")!;
       const commentContent = element
-        .querySelector(".comment")
-        .querySelector(".info")
-        .querySelector(".content")
+        .querySelector(".comment")!
+        .querySelector(".info")!
+        .querySelector(".content")!
         .innerHTML.trim();
 
       // get replies
       let replies: ProfileCommentReply[] = [];
       let replyList = element
-        .querySelector(".replies")
+        .querySelector(".replies")!
         .querySelectorAll(".reply");
       for (let replyID in replyList) {
         const reply = replyList[replyID];
         if (reply.tagName === "A") continue;
         if (typeof reply === "function") continue;
         if (typeof reply === "number") continue;
-        const commentID = reply.querySelector(".comment").id;
+        const commentID = reply.querySelector(".comment")!.id;
         const commentPoster = reply
-          .querySelector(".comment")
+          .querySelector(".comment")!
           .getElementsByTagName("a")[0]
-          .getAttribute("data-comment-user");
+          .getAttribute("data-comment-user")!;
 
         // regex here developed at https://scratch.mit.edu/discuss/post/5983094/
         const commentContent = reply
-          .querySelector(".comment")
-          .querySelector(".info")
-          .querySelector(".content")
+          .querySelector(".comment")!
+          .querySelector(".info")!
+          .querySelector(".content")!
           .textContent.trim()
           .replace(/\n+/gm, "")
           .replace(/\s+/gm, " ");
@@ -260,6 +264,7 @@ class Profile {
    * Toggle the comments section on the profile
    */
   async toggleComments() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(`https://scratch.mit.edu/site-api/comments/user/${this.user}/toggle-comments/`, {
       method: "POST",
       headers: {
diff --git a/src/classes/Project.ts b/src/classes/Project.ts
index 8b0217e..b913daa 100644
--- a/src/classes/Project.ts
+++ b/src/classes/Project.ts
@@ -173,6 +173,7 @@ class Project {
    * @param commentee_id The ID of the user to ping in the starting
    */
   async comment(content: string, parent_id?: number, commentee_id?: number) {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://api.scratch.mit.edu/proxy/comments/project/${this.id}`,
       {
@@ -207,6 +208,7 @@ class Project {
   }
 
   async setCommentsAllowed(state: boolean) {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(`https://api.scratch.mit.edu/projects/${this.id}`, {
       method: "PUT",
       body: JSON.stringify({
@@ -227,6 +229,7 @@ class Project {
    * @param value The value you want to set the title to.
    */
   async setTitle(value: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const setFetch = await fetch(
       `https://api.scratch.mit.edu/projects/${this.id}`,
       {
@@ -254,6 +257,7 @@ class Project {
    * @param value The value you want to set the instructions to.
    */
   async setInstructions(value: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const setFetch = await fetch(
       `https://api.scratch.mit.edu/projects/${this.id}`,
       {
@@ -282,6 +286,7 @@ class Project {
    * @param value The value you want to set the Notes and Credits to.
    */
   async setNotesAndCredits(value: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const setFetch = await fetch(
       `https://api.scratch.mit.edu/projects/${this.id}`,
       {
@@ -310,6 +315,7 @@ class Project {
    * @param buffer The buffer of the thumbnail image file
    */
   async setThumbnail(buffer: Buffer) {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://scratch.mit.edu/internalapi/project/thumbnail/${this.id}/set/`,
       {
@@ -331,6 +337,7 @@ class Project {
    * Unshares the project (requires ownership of the project).
    */
   async unshare() {
+    if(!this.session) throw Error("You need to be logged in")
     const setFetch = await fetch(
       `https://scratch.mit.edu/site-api/projects/all/${this.id}/`,
       {
@@ -359,6 +366,7 @@ class Project {
    * Check if the user is loving the project
    */
   async isLoving() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://api.scratch.mit.edu/projects/${this.id}/loves/user/${this.session.sessionJSON.user.username}`,
       {
@@ -382,6 +390,7 @@ class Project {
    * Check if the user is favoriting the project
    */
   async isFavoriting() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://api.scratch.mit.edu/projects/${this.id}/favorites/user/${this.session.sessionJSON.user.username}`,
       {
@@ -407,6 +416,7 @@ class Project {
    * @param loving Either true or false
    */
   async setLoving(loving: boolean) {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://api.scratch.mit.edu/proxy/projects/${this.id}/loves/user/${this.session.sessionJSON.user.username}`,
       {
@@ -439,6 +449,7 @@ class Project {
    * @param favoriting Either true or false
    */
   async setFavoriting(favoriting: boolean) {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://api.scratch.mit.edu/proxy/projects/${this.id}/favorites/user/${this.session.sessionJSON.user.username}`,
       {
@@ -469,6 +480,7 @@ class Project {
    * Shares the project (requires ownership of the project).
    */
   async share() {
+    if(!this.session) throw Error("You need to be logged in")
     const setFetch = await fetch(
       `https://api.scratch.mit.edu/proxy/projects/${this.id}/share/`,
       {
diff --git a/src/classes/Studio.ts b/src/classes/Studio.ts
index 07e0542..83eb2ad 100644
--- a/src/classes/Studio.ts
+++ b/src/classes/Studio.ts
@@ -70,6 +70,7 @@ class Studio {
    * Follow the studio
    */
   async follow() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://scratch.mit.edu/site-api/users/bookmarkers/${this.id}/add/?usernames=${this.session.sessionJSON.user.username}`,
       {
@@ -94,6 +95,7 @@ class Studio {
    * Unfollow the studio
    */
   async unfollow() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://scratch.mit.edu/site-api/users/bookmarkers/${this.id}/remove/?usernames=${this.session.sessionJSON.user.username}`,
       {
@@ -119,6 +121,7 @@ class Studio {
    * @param value The value to set the title to.
    */
   async setTitle(value: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const setFetch = await fetch(
       `https://scratch.mit.edu/site-api/galleries/all/${this.id}/`,
       {
@@ -143,6 +146,7 @@ class Studio {
    * @param value The value to set the description to.
    */
   async setDescription(value: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const setFetch = await fetch(
       `https://scratch.mit.edu/site-api/galleries/all/${this.id}/`,
       {
@@ -167,6 +171,7 @@ class Studio {
    * @param username The username of the user to add.
    */
   async inviteCurator(username: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const inviteFetch = await fetch(
       `https://scratch.mit.edu/site-api/users/curators-in/${this.id}/invite_curator/?usernames=${username}`,
       {
@@ -190,6 +195,7 @@ class Studio {
    * @param username The username of the user to remove.
    */
   async removeCurator(username: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const removeFetch = await fetch(
       `https://scratch.mit.edu/site-api/users/curators-in/${this.id}/remove/?usernames=${username}`,
       {
@@ -213,6 +219,7 @@ class Studio {
    * @param project The project ID to add to the studio.
    */
   async addProject(project: number) {
+    if(!this.session) throw Error("You need to be logged in")
     const addFetch = await fetch(
       `https://api.scratch.mit.edu/studios/${this.id}/project/${project}`,
       {
@@ -233,6 +240,7 @@ class Studio {
    * @param project The project ID to remove from the studio.
    */
   async removeProject(project: number) {
+    if(!this.session) throw Error("You need to be logged in")
     const removeFetch = await fetch(
       `https://api.scratch.mit.edu/studios/${this.id}/project/${project}`,
       {
@@ -255,6 +263,7 @@ class Studio {
    * @param commentee_id The ID of the user to ping in the starting
    */
   async comment(content: string, parent_id?: number, commentee_id?: number) {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(
       `https://api.scratch.mit.edu/proxy/comments/studio/${this.id}`,
       {
@@ -292,6 +301,7 @@ class Studio {
    * Toggle comments on or off
    */
   async toggleComments() {
+    if(!this.session) throw Error("You need to be logged in")
     const request = await fetch(`https://scratch.mit.edu/site-api/comments/gallery/${this.id}/toggle-comments/`, {
       method: "POST",
       headers: {
diff --git a/src/classes/forums/Forum.ts b/src/classes/forums/Forum.ts
index 1635aa0..3b85ea5 100644
--- a/src/classes/forums/Forum.ts
+++ b/src/classes/forums/Forum.ts
@@ -37,17 +37,17 @@ class Forum {
       );
     }
     const dom = parse(await res.text());
-    const listDOMElement = dom.querySelector(".topic.list");
+    const listDOMElement = dom.querySelector(".topic.list")!;
     const children = listDOMElement.getElementsByTagName("li");
     children.forEach((child) => {
       const id = child
         .getElementsByTagName("a")[0]
-        .getAttribute("href")
+        .getAttribute("href")!
         .split("/")
         .splice(1)[3];
-      const title = child.querySelector("strong").innerText;
+      const title = child.querySelector("strong")!.innerText;
       const replyCount = Number(
-        child.querySelector(".item span").innerText.split(" ")[0]
+        child.querySelector(".item span")!.innerText.split(" ")[0]
       );
       const isSticky = child.classList.contains("sticky");
       const topic = new Topic({
@@ -69,6 +69,7 @@ class Forum {
    * @param body The body of the topic
    */
   async createTopic(title: string, body: string) {
+    if(!this.session) throw Error("You need to be logged in");
     if (!this.id) throw Error("You need to add a forum id");
     const form = new FormData();
     form.append("csrfmiddlewaretoken", this.session.csrfToken);
@@ -107,6 +108,7 @@ class Forum {
    * @param content The content to set the signature to
    */
   async setSignature(content: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const editFetch = await fetch(
       `https://scratch.mit.edu/discuss/settings/${this.session.sessionJSON.user.username}/`,
       {
diff --git a/src/classes/forums/Post.ts b/src/classes/forums/Post.ts
index 54d3a20..afa3793 100644
--- a/src/classes/forums/Post.ts
+++ b/src/classes/forums/Post.ts
@@ -46,6 +46,7 @@ class Post {
    * @param content The new content of the post
    */
   async edit(content: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const editFetch = await fetch(
       `https://scratch.mit.edu/discuss/post/${this.id}/edit/`,
       {
diff --git a/src/classes/forums/Topic.ts b/src/classes/forums/Topic.ts
index 9f43e2c..0e14ccc 100644
--- a/src/classes/forums/Topic.ts
+++ b/src/classes/forums/Topic.ts
@@ -37,7 +37,7 @@ class Topic {
    * @returns An array of posts in the topic.
    */
   async getPosts(page: number = 1) {
-    let posts = [];
+    let posts: Post[] = [];
 
     const res = await fetch(
       `https://scratch.mit.edu/discuss/m/topic/${this.id}/?page=${page}`,
@@ -54,14 +54,14 @@ class Topic {
     }
     const dom = parse(await res.text());
     const children = dom
-      .querySelector(".content")
+      .querySelector(".content")!
       .getElementsByTagName("article");
     children.forEach((child) => {
-      const id = child.getAttribute("id").split("-")[1];
-      const content = child.querySelector(".post-content").innerHTML;
-      const parsableContent = child.querySelector(".post-content");
+      const id = child.getAttribute("id")!.split("-")[1];
+      const content = child.querySelector(".post-content")!.innerHTML;
+      const parsableContent = child.querySelector(".post-content")!;
       const time = new Date(
-        child.querySelector("time").getAttribute("datetime")
+        child.querySelector("time")!.getAttribute("datetime")!
       );
       const post = new Post({
         id: Number(id),
@@ -84,6 +84,7 @@ class Topic {
    * @param body The body of the post
    */
   async reply(body: string) {
+    if(!this.session) throw Error("You need to be logged in")
     const form = new FormData();
     form.append("csrfmiddlewaretoken", this.session.csrfToken);
     form.append("body", body);
@@ -119,6 +120,7 @@ class Topic {
    * Follows the topic.
    */
   async follow() {
+    if(!this.session) throw Error("You need to be logged in")
     const followFetch = await fetch(
       `https://scratch.mit.edu/discuss/subscription/topic/${this.id}/add/`,
       {
@@ -148,6 +150,7 @@ class Topic {
    * Unfollows the topic.
    */
   async unfollow() {
+    if(!this.session) throw Error("You need to be logged in")
     const unfollowFetch = await fetch(
       `https://scratch.mit.edu/discuss/subscription/topic/${this.id}/delete/`,
       {
diff --git a/src/utils.ts b/src/utils.ts
index 04ddfc4..bb50c08 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,7 +1,7 @@
 import { Readable } from "node:stream";
 // https://stackoverflow.com/a/49428486/17333186
 export function streamToString(stream: Readable): Promise<string> {
-  let chunks = [];
+  let chunks: Buffer[] = [];
   return new Promise((resolve, reject) => {
     stream.on("data", (chunk) => chunks.push(Buffer.from(chunk)));
     stream.on("error", (err) => reject(err));
diff --git a/tsconfig.json b/tsconfig.json
index 528b04b..862bebf 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -6,6 +6,7 @@
     "allowSyntheticDefaultImports": true,
     "esModuleInterop": true,
     "module": "es2022",
-    "target": "es2020"
+    "target": "es2020",
+    "strict": true
   }
 }