diff --git a/core/src/index.ts b/core/src/index.ts
index 3192a229..a2550bca 100644
--- a/core/src/index.ts
+++ b/core/src/index.ts
@@ -71,7 +71,10 @@ function emitCreated(store: InternalStore, state: any): void {
     eventEmitter.once(EVENTS.core.installed, created);
 }
 
-function getExtendedStore<TState extends BaseState, TExtensions extends Extension<TState>[]>(store: InternalStore<TState>, extensions: TExtensions): ReturnType<Extension<TState>> {
+function getExtendedStore<TState extends BaseState, TExtensions extends Extension<TState>[]>(
+    store: InternalStore<TState>,
+    extensions: TExtensions
+): ReturnType<Extension<TState>> {
     return extensions.reduce((output, extension) => {
         let result = {};
 
@@ -114,7 +117,7 @@ function installPlugin(plugin: HarlemPlugin, app: App): void {
 export const on = eventEmitter.on.bind(eventEmitter);
 export const once = eventEmitter.once.bind(eventEmitter);
 
-export function createStore<TState extends BaseState, TExtensions extends Extension<TState>[]>(
+export function createStore<TState extends BaseState, TExtensions extends Extension<TState>[] = []>(
     name: string,
     state: TState,
     options?: Partial<StoreOptions<TState, TExtensions>>
diff --git a/core/src/types.ts b/core/src/types.ts
index e296323f..a65072f9 100644
--- a/core/src/types.ts
+++ b/core/src/types.ts
@@ -6,7 +6,6 @@ import type {
 
 type UnionToIntersection<TValue> = (TValue extends any ? (arg: TValue) => any : never) extends ((arg: infer I) => void) ? I : never;
 
-//export type BaseState = object;
 export type BaseState = Record<PropertyKey, any>;
 export type StoreProvider<TState extends BaseState> = keyof StoreProviders<TState>;
 export type ReadState<TState extends BaseState> = DeepReadonly<TState>;
@@ -23,11 +22,10 @@ export type EventHandler<TData = any> = (payload?: EventPayload<TData>) => void;
 export type TriggerHandler<TEventData extends TriggerEventData> = (data: TEventData) => void;
 export type Trigger<TEventData extends TriggerEventData> = (name: string | string[], handler: TriggerHandler<TEventData>) => EventListener;
 export type BranchAccessor<TState extends BaseState, TBranchState extends BaseState> = (state: ReadState<TState> | WriteState<TState>) => TBranchState;
-export type InternalStores = Map<string, InternalStore<any>>;
+export type InternalStores = Map<string, InternalStore<BaseState>>;
 export type Extension<TState extends BaseState> = (store: InternalStore<TState>) => Record<string, any>;
-export type ExtensionAPIs<TExtensions extends Extension<any>[]> = UnionToIntersection<ReturnType<TExtensions[number]>>;
-export type PublicStore<TState extends BaseState, TExtensions extends Extension<TState>[]> = Store<TState> & ExtensionAPIs<TExtensions>;
-// export type PublicStore<TState extends BaseState, TExtensions extends Extension<TState>[]> = Omit<Store<TState>, keyof ExtensionAPIs<TExtensions>> & ExtensionAPIs<TExtensions>
+export type ExtensionAPIs<TExtensions extends Extension<BaseState>[]> = UnionToIntersection<ReturnType<TExtensions[number]>>;
+export type PublicStore<TState extends BaseState, TExtensions extends Extension<TState>[]> = Omit<Store<TState>, keyof ExtensionAPIs<TExtensions>> & ExtensionAPIs<TExtensions>
 
 export interface Emittable {
     on(event: string, handler: EventHandler): EventListener;
@@ -158,7 +156,7 @@ export interface StoreProviders<TState extends BaseState> {
     payload<TPayload>(payload: TPayload): TPayload;
 }
 
-export interface InternalStore<TState extends BaseState = any> extends StoreBase<TState> {
+export interface InternalStore<TState extends BaseState = BaseState> extends StoreBase<TState> {
     /**
      * A boolean indicating whether this store allows overwriting duplicate registrations
      */
diff --git a/core/test/index.test.ts b/core/test/index.test.ts
index 84bb45a4..c92224d7 100644
--- a/core/test/index.test.ts
+++ b/core/test/index.test.ts
@@ -8,7 +8,9 @@ import Harlem, {
 } from '../src';
 
 import {
+    App,
     isRef,
+    Plugin,
     ref,
 } from 'vue';
 
@@ -46,12 +48,6 @@ function getStore() {
         [internalKey]: 10,
     }, {
         allowOverwrite: false,
-        // extensions: [
-        //     store => ({
-        //         blah: 5,
-        //         //action: () => 6
-        //     }),
-        // ],
     });
 
     const fullName = getter('fullname', ({ details }) => `${details.firstName} ${details.lastName}`);
@@ -88,12 +84,12 @@ describe('Harlem Core', () => {
 
     beforeAll(() => {
         const app = {
-            use: (plugin: any, options?: any) => {
+            use: (plugin: Plugin, options?: any) => {
                 if (plugin && plugin.install){
                     plugin.install(app, options);
                 }
             },
-        };
+        } as App;
 
         app.use(Harlem);
     });