diff --git a/src/communicator.ts b/src/communicator.ts
index 2525362..a568232 100644
--- a/src/communicator.ts
+++ b/src/communicator.ts
@@ -1,5 +1,5 @@
 import net from "net";
-import { FLAP, SNAC, TLV } from './structures';
+import { FLAP, SNAC, TLV, TLVType } from './structures';
 import { logDataStream } from './util';
 import { FLAGS_EMPTY } from './consts';
 
@@ -29,6 +29,7 @@ export default class Communicator {
 
   start() {
     // Start negotiating a connection 
+    console.log(FLAP, typeof FLAP);
     const hello = new FLAP(0x01, 0, Buffer.from([0x00, 0x00, 0x00, 0x01]));
     this.send(hello);
   }
@@ -78,19 +79,18 @@ export default class Communicator {
         const tlv = TLV.fromBuffer(message.payload.slice(4));
         console.log(tlv.toString());
 
-        switch (tlv.type) {
-          case 0x06: // Requesting available services
-            // this is just a dword list of service families
-            const servicesOffered : Buffer[] = [];
-            Object.values(this.services).forEach((service) => {
-              servicesOffered.push(Buffer.from([0x00, service.family]));
-            });
-            const resp = new FLAP(2, this._getNewSequenceNumber(),
-              new SNAC(0x01, 0x03, FLAGS_EMPTY, 0, [
-                Buffer.concat(servicesOffered),
-              ]));
-            this.send(resp);
-            return;
+        if (tlv.type === TLVType.GetServices) { // Requesting available services
+          // this is just a dword list of service families
+          const servicesOffered : Buffer[] = [];
+          Object.values(this.services).forEach((service) => {
+            servicesOffered.push(Buffer.from([0x00, service.family]));
+          });
+          const resp = new FLAP(2, this._getNewSequenceNumber(),
+            new SNAC(0x01, 0x03, FLAGS_EMPTY, 0, [
+              Buffer.concat(servicesOffered),
+            ]));
+          this.send(resp);
+          return;
         }
 
         return;
diff --git a/src/services/authorization-registration.ts b/src/services/authorization-registration.ts
index 97558ab..99e7acf 100644
--- a/src/services/authorization-registration.ts
+++ b/src/services/authorization-registration.ts
@@ -1,7 +1,7 @@
 import crypto from 'crypto';
 import BaseService from './base';
 import Communicator from '../communicator';
-import { FLAP, SNAC, TLV } from '../structures';
+import { FLAP, SNAC, TLV, ErrorCode, TLVType } from '../structures';
 
 const { AIM_MD5_STRING, FLAGS_EMPTY } = require('../consts');
 
@@ -26,13 +26,13 @@ export default class AuthorizationRegistrationService extends BaseService {
     switch (message.payload.service) {
       case 0x02: // Client login request (md5 login sequence)
         const tlvs = message.payload.tlvs;
-        const clientNameTLV = tlvs.find((tlv) => tlv instanceof TLV && tlv.type === 0x03);
+        const clientNameTLV = tlvs.find((tlv) => tlv instanceof TLV && tlv.type === TLVType.ClientName);
         if (!clientNameTLV || !(clientNameTLV instanceof TLV)) {
           return;
         }
         console.log("Attempting connection from", clientNameTLV.payload.toString('ascii'));
 
-        const userTLV = tlvs.find((tlv) => tlv instanceof TLV && tlv.type === 0x01);
+        const userTLV = tlvs.find((tlv) => tlv instanceof TLV && tlv.type === TLVType.User);
         if (!userTLV  || !(userTLV instanceof TLV)) {
           return;
         }
@@ -42,15 +42,15 @@ export default class AuthorizationRegistrationService extends BaseService {
         if (!users[username]) {
           const authResp = new FLAP(2, this._getNewSequenceNumber(),
           new SNAC(0x17, 0x03, FLAGS_EMPTY, 0, [
-            new TLV(0x0001, Buffer.from(username)), // username
-            new TLV(0x0008, Buffer.from([0x00, 0x04])) // incorrect nick/password
+            TLV.forUsername(username), // username
+            TLV.forError(ErrorCode.IncorrectNick) // incorrect nick/password
           ]));
           
           this.send(authResp);
           return;
         }
 
-        const passwordHashTLV = tlvs.find((tlv) => tlv instanceof TLV && tlv.type === 0x25);
+        const passwordHashTLV = tlvs.find((tlv) => tlv instanceof TLV && tlv.type === TLVType.PasswordHash);
         if (!passwordHashTLV || !(passwordHashTLV instanceof TLV)) {
           return;
         }
@@ -65,8 +65,8 @@ export default class AuthorizationRegistrationService extends BaseService {
           console.log('Invalid password for', username);
           const authResp = new FLAP(2, this._getNewSequenceNumber(),
           new SNAC(0x17, 0x03, FLAGS_EMPTY, 0, [
-            new TLV(0x0001, Buffer.from(username)), // username
-            new TLV(0x0008, Buffer.from([0x00, 0x04])) // incorrect nick/password
+            TLV.forUsername(username), // username
+            TLV.forError(ErrorCode.IncorrectNick) // incorrect nick/password
           ]));
           this.send(authResp);
           return;
@@ -74,9 +74,9 @@ export default class AuthorizationRegistrationService extends BaseService {
 
         const authResp = new FLAP(2, this._getNewSequenceNumber(),
         new SNAC(0x17, 0x03, FLAGS_EMPTY, 0, [
-          new TLV(0x01, Buffer.from(username)), // username
-          new TLV(0x05, Buffer.from('10.0.1.29:5190')), // BOS address
-          new TLV(0x06, Buffer.from('im a cookie uwu')) // Authorization cookie
+          TLV.forUsername(username), // username
+          TLV.forBOSAddress('10.0.1.29:5190'), // BOS address
+          TLV.forCookie('im a cookie uwu') // Authorization cookie
         ]));
 
         this.send(authResp);
diff --git a/src/structures.ts b/src/structures.ts
deleted file mode 100644
index 41898ef..0000000
--- a/src/structures.ts
+++ /dev/null
@@ -1,148 +0,0 @@
-import assert from 'assert';
-
-import { logDataStream } from './util';
-
-export class TLV {
-  static fromBuffer(buf : Buffer) {
-    const type = buf.slice(0, 2).readInt16BE(0);
-    const len = buf.slice(2, 4).readInt16BE(0)
-    const payload = buf.slice(4, 4 + len);
-
-    return new TLV(type, payload);
-  }
-
-  public len : number;
-
-  constructor(public type : number, public payload : Buffer) {
-    this.type = type;
-    this.len = payload.length;
-    this.payload = payload;
-  }
-
-  toString() {
-    return `TLV(0x${this.type.toString(16).padStart(2, '0')}, ${this.len}, ${this.payload.toString('ascii')})`;
-  }
-
-  toBuffer() {
-    const TLVHeader = Buffer.alloc(4, 0, 'hex');
-    TLVHeader.writeUInt16BE(this.type);
-    TLVHeader.writeUInt16BE(this.len, 2);
-    return Buffer.concat([TLVHeader, this.payload]);
-  }
-}
-
-export class SNAC {
-  static fromBuffer(buf : Buffer, payloadLength = 0) {
-    assert(buf.length >= 10, 'Expected 10 bytes for SNAC header');
-    const family = buf.slice(0,2).readInt16BE(0);
-    const service = buf.slice(2,4).readInt16BE(0);
-    const flags = buf.slice(4, 6);
-    const requestID = buf.slice(6, 10).readInt32BE(0);
-    const tlvs : TLV[] = []; // SNACs can have multiple TLVs
-
-    let tlvsIdx = 10;
-    let cb = 0, cbLimit = 20; //circuit breaker
-    while (tlvsIdx < payloadLength && cb < cbLimit) {
-      const tlv = TLV.fromBuffer(buf.slice(tlvsIdx));
-      tlvs.push(tlv);
-      tlvsIdx += tlv.len + 4; // 4 bytes for TLV type + tlvs length
-      cb++;
-    }
-    if (cb === cbLimit) {
-      console.error('Application error, cb limit reached');
-      process.exit(1);
-    }
-    
-    return new SNAC(family, service, flags, requestID, tlvs);
-  }
-
-  constructor(public family : number, public service : number, public flags : Buffer, public requestID : number , public tlvs : Array<TLV | Buffer> = []) {
-    this.family = family;
-    this.service = service;
-    this.flags = flags;
-    this.requestID = requestID;
-    this.tlvs = tlvs;
-  }
-
-  toString() {
-    return `SNAC(${this.family.toString(16)},${this.service.toString(16)}) #${this.requestID}\n  ${this.tlvs}`;
-  }
-
-  toBuffer() {
-    const SNACHeader = Buffer.alloc(10, 0, 'hex');
-    SNACHeader.writeUInt16BE(this.family);
-    SNACHeader.writeUInt16BE(this.service, 2);
-    SNACHeader.set(this.flags, 4);
-    SNACHeader.writeUInt32BE(this.requestID, 6);
-
-    const payload = this.tlvs.map((thing) => {
-      if (thing instanceof TLV) {
-        return thing.toBuffer();
-      }
-      return thing;
-    });
-
-    return Buffer.concat([SNACHeader, ...payload]);
-  }
-}
-
-export class FLAP {
-  static fromBuffer(buf : Buffer) {
-    assert.equal(buf[0], 0x2a, 'Expected 0x2a at start of FLAP header');
-    assert(buf.length >= 6, 'Expected at least 6 bytes for FLAP header');
-    const channel = buf.readInt8(1);
-    const sequenceNumber = buf.slice(2,4).readInt16BE(0);
-    const payloadLength = buf.slice(4, 6).readInt16BE(0);
-    let payload : Buffer | SNAC = buf.slice(6, 6 + payloadLength);
-
-    if (channel === 2) {
-      payload = SNAC.fromBuffer(payload, payloadLength);
-    }
-
-    return new FLAP(channel, sequenceNumber, payload)
-  }
-
-  payloadLength: number;
-
-  constructor(public channel: number, public sequenceNumber: number, public payload: Buffer | SNAC) {
-    this.channel = channel;
-    this.sequenceNumber = sequenceNumber;
-
-    this.payload = payload;
-
-    if (payload instanceof SNAC) {
-      this.payloadLength = payload.toBuffer().length;
-    } else {
-      this.payloadLength = payload.length;
-    }
-  }
-
-  toString() {
-    let payload = this.payload.toString();
-    if (this.payload instanceof Buffer) {
-      payload = logDataStream(this.payload).split('\n').join('\n  ');
-    }
-    return `ch:${this.channel}, dn: ${this.sequenceNumber}, len: ${this.payloadLength}, payload:\n  ${payload}`
-  }
-
-  toBuffer() {
-    const FLAPHeader = Buffer.alloc(6, 0, 'hex');
-    FLAPHeader.writeInt8(0x2a, 0);
-    FLAPHeader.writeInt8(this.channel, 1);
-    FLAPHeader.writeInt16BE(this.sequenceNumber, 2);
-    FLAPHeader.writeInt16BE(this.payloadLength, 4);
-
-    let payload = this.payload;
-    if (payload instanceof SNAC) {
-      payload = payload.toBuffer();
-    }
-
-    return Buffer.concat([FLAPHeader, payload]);
-  }
-}
-
-module.exports = {
-  TLV,
-  SNAC,
-  FLAP,
-};
diff --git a/src/structures/ErrorCode.ts b/src/structures/ErrorCode.ts
new file mode 100644
index 0000000..b82a195
--- /dev/null
+++ b/src/structures/ErrorCode.ts
@@ -0,0 +1,3 @@
+export const enum ErrorCode {
+  IncorrectNick = 0x04,
+}
diff --git a/src/structures/FLAP.ts b/src/structures/FLAP.ts
new file mode 100644
index 0000000..215cce2
--- /dev/null
+++ b/src/structures/FLAP.ts
@@ -0,0 +1,59 @@
+import assert from "assert"
+
+import { SNAC } from "./SNAC";
+import { logDataStream } from '../util';
+
+export class FLAP {
+  static fromBuffer(buf : Buffer) {
+    assert.equal(buf[0], 0x2a, 'Expected 0x2a at start of FLAP header');
+    assert(buf.length >= 6, 'Expected at least 6 bytes for FLAP header');
+    const channel = buf.readInt8(1);
+    const sequenceNumber = buf.slice(2,4).readInt16BE(0);
+    const payloadLength = buf.slice(4, 6).readInt16BE(0);
+    let payload : Buffer | SNAC = buf.slice(6, 6 + payloadLength);
+
+    if (channel === 2) {
+      payload = SNAC.fromBuffer(payload, payloadLength);
+    }
+
+    return new FLAP(channel, sequenceNumber, payload)
+  }
+
+  payloadLength: number;
+
+  constructor(public channel: number, public sequenceNumber: number, public payload: Buffer | SNAC) {
+    this.channel = channel;
+    this.sequenceNumber = sequenceNumber;
+
+    this.payload = payload;
+
+    if (payload instanceof SNAC) {
+      this.payloadLength = payload.toBuffer().length;
+    } else {
+      this.payloadLength = payload.length;
+    }
+  }
+
+  toString() {
+    let payload = this.payload.toString();
+    if (this.payload instanceof Buffer) {
+      payload = logDataStream(this.payload).split('\n').join('\n  ');
+    }
+    return `ch:${this.channel}, dn: ${this.sequenceNumber}, len: ${this.payloadLength}, payload:\n  ${payload}`
+  }
+
+  toBuffer() {
+    const FLAPHeader = Buffer.alloc(6, 0, 'hex');
+    FLAPHeader.writeInt8(0x2a, 0);
+    FLAPHeader.writeInt8(this.channel, 1);
+    FLAPHeader.writeInt16BE(this.sequenceNumber, 2);
+    FLAPHeader.writeInt16BE(this.payloadLength, 4);
+
+    let payload = this.payload;
+    if (payload instanceof SNAC) {
+      payload = payload.toBuffer();
+    }
+
+    return Buffer.concat([FLAPHeader, payload]);
+  }
+}
diff --git a/src/structures/SNAC.ts b/src/structures/SNAC.ts
new file mode 100644
index 0000000..4224b13
--- /dev/null
+++ b/src/structures/SNAC.ts
@@ -0,0 +1,57 @@
+import assert from "assert";
+import { TLV } from "./TLV";
+
+export class SNAC {
+  static fromBuffer(buf : Buffer, payloadLength = 0) {
+    assert(buf.length >= 10, 'Expected 10 bytes for SNAC header');
+    const family = buf.slice(0,2).readInt16BE(0);
+    const service = buf.slice(2,4).readInt16BE(0);
+    const flags = buf.slice(4, 6);
+    const requestID = buf.slice(6, 10).readInt32BE(0);
+    const tlvs : TLV[] = []; // SNACs can have multiple TLVs
+
+    let tlvsIdx = 10;
+    let cb = 0, cbLimit = 20; //circuit breaker
+    while (tlvsIdx < payloadLength && cb < cbLimit) {
+      const tlv = TLV.fromBuffer(buf.slice(tlvsIdx));
+      tlvs.push(tlv);
+      tlvsIdx += tlv.length + 4; // 4 bytes for TLV type + tlvs length
+      cb++;
+    }
+    if (cb === cbLimit) {
+      console.error('Application error, cb limit reached');
+      process.exit(1);
+    }
+    
+    return new SNAC(family, service, flags, requestID, tlvs);
+  }
+
+  constructor(public family : number, public service : number, public flags : Buffer, public requestID : number , public tlvs : Array<TLV | Buffer> = []) {
+    this.family = family;
+    this.service = service;
+    this.flags = flags;
+    this.requestID = requestID;
+    this.tlvs = tlvs;
+  }
+
+  toString() {
+    return `SNAC(${this.family.toString(16)},${this.service.toString(16)}) #${this.requestID}\n  ${this.tlvs}`;
+  }
+
+  toBuffer() {
+    const SNACHeader = Buffer.alloc(10, 0, 'hex');
+    SNACHeader.writeUInt16BE(this.family);
+    SNACHeader.writeUInt16BE(this.service, 2);
+    SNACHeader.set(this.flags, 4);
+    SNACHeader.writeUInt32BE(this.requestID, 6);
+
+    const payload = this.tlvs.map((thing) => {
+      if (thing instanceof TLV) {
+        return thing.toBuffer();
+      }
+      return thing;
+    });
+
+    return Buffer.concat([SNACHeader, ...payload]);
+  }
+}
diff --git a/src/structures/TLV.ts b/src/structures/TLV.ts
new file mode 100644
index 0000000..8c544c2
--- /dev/null
+++ b/src/structures/TLV.ts
@@ -0,0 +1,54 @@
+import {ErrorCode} from "./ErrorCode";
+
+export const enum TLVType {
+  User = 0x01,
+  ClientName = 0x03,
+  GetServices = 0x06,
+  PasswordHash = 0x25,
+}
+
+export class TLV {
+  get length() : number {
+    return this.payload.length;
+  }
+
+  static fromBuffer(buf : Buffer) {
+    const type = buf.slice(0, 2).readInt16BE(0) as TLVType;
+    const len = buf.slice(2, 4).readInt16BE(0)
+    const payload = buf.slice(4, 4 + len);
+
+    return new TLV(type, payload);
+  }
+
+  static forUsername(username : string) : TLV {
+    return new TLV(0x01, Buffer.from(username));
+  }
+
+  static forBOSAddress(address : string ) : TLV {
+    return new TLV(0x05, Buffer.from(address));
+  }
+
+  static forCookie(cookie : string) : TLV {
+    return new TLV(0x06, Buffer.from(cookie));
+  }
+
+  static forError(errorCode : ErrorCode) : TLV {
+    return new TLV(0x08, Buffer.from([0x00, errorCode]));
+  }
+
+  constructor(public type : TLVType, public payload : Buffer) {
+    this.type = type;
+    this.payload = payload;
+  }
+
+  toString() {
+    return `TLV(0x${this.type.toString(16).padStart(2, '0')}, ${this.length}, ${this.payload.toString('ascii')})`;
+  }
+
+  toBuffer() {
+    const TLVHeader = Buffer.alloc(4, 0, 'hex');
+    TLVHeader.writeUInt16BE(this.type);
+    TLVHeader.writeUInt16BE(this.length, 2);
+    return Buffer.concat([TLVHeader, this.payload]);
+  }
+}
diff --git a/src/structures/index.ts b/src/structures/index.ts
new file mode 100644
index 0000000..5724018
--- /dev/null
+++ b/src/structures/index.ts
@@ -0,0 +1,4 @@
+export * from "./ErrorCode";
+export * from "./TLV";
+export * from "./SNAC";
+export * from "./FLAP";
diff --git a/tsconfig.json b/tsconfig.json
index 28ee738..6bacef8 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,6 +2,7 @@
   "extends": "@tsconfig/node14/tsconfig.json",
   "compilerOptions": {
     "preserveConstEnums": true,
+    "esModuleInterop": true,
     "outDir": "./dist",
   },
   "include": ["src/**/*"],