diff --git a/demo/src/components/CurrentSlide.tsx b/demo/src/components/CurrentSlide.tsx
index bb9d68ad..97486756 100644
--- a/demo/src/components/CurrentSlide.tsx
+++ b/demo/src/components/CurrentSlide.tsx
@@ -10,7 +10,7 @@ interface Props {
 export const CurrentSlide = ({ slides }: Props) => {
   const containerRef = useRef<HTMLDivElement>(null);
   const { self } = useMembers();
-  const slide = self?.location?.slide || 0;
+  const slide = parseInt(self?.location?.slide || '', 10) || 0;
 
   useTrackCursor(containerRef);
 
diff --git a/demo/tsconfig.json b/demo/tsconfig.json
index 6cb7ec2d..a7fc6fbf 100644
--- a/demo/tsconfig.json
+++ b/demo/tsconfig.json
@@ -15,7 +15,7 @@
     "jsx": "react-jsx",
 
     /* Linting */
-    "strict": false,
+    "strict": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
     "noFallthroughCasesInSwitch": true
diff --git a/package-lock.json b/package-lock.json
index e043b8ba..96fde898 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -23,6 +23,7 @@
         "husky": "^8.0.0",
         "mock-socket": "^9.1.5",
         "prettier": "^2.8.3",
+        "rollup": "^3.28.0",
         "typescript": "^4.9.5",
         "vitest": "^0.29.8"
       }
@@ -3832,9 +3833,9 @@
       }
     },
     "node_modules/rollup": {
-      "version": "3.23.1",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.23.1.tgz",
-      "integrity": "sha512-ybRdFVHOoljGEFILHLd2g/qateqUdjE6YS41WXq4p3C/WwD3xtWxV4FYWETA1u9TeXQc5K8L8zHE5d/scOvrOQ==",
+      "version": "3.28.0",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.28.0.tgz",
+      "integrity": "sha512-d7zhvo1OUY2SXSM6pfNjgD5+d0Nz87CUp4mt8l/GgVP3oBsPwzNvSzyu1me6BSG9JIgWNTVcafIXBIyM8yQ3yw==",
       "dev": true,
       "bin": {
         "rollup": "dist/bin/rollup"
@@ -7384,9 +7385,9 @@
       }
     },
     "rollup": {
-      "version": "3.23.1",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.23.1.tgz",
-      "integrity": "sha512-ybRdFVHOoljGEFILHLd2g/qateqUdjE6YS41WXq4p3C/WwD3xtWxV4FYWETA1u9TeXQc5K8L8zHE5d/scOvrOQ==",
+      "version": "3.28.0",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.28.0.tgz",
+      "integrity": "sha512-d7zhvo1OUY2SXSM6pfNjgD5+d0Nz87CUp4mt8l/GgVP3oBsPwzNvSzyu1me6BSG9JIgWNTVcafIXBIyM8yQ3yw==",
       "dev": true,
       "requires": {
         "fsevents": "~2.3.2"
diff --git a/package.json b/package.json
index 011cf65c..3337b423 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "build": "npm run build:mjs && npm run build:cjs && npm run build:iife",
     "build:mjs": "npx tsc --project tsconfig.mjs.json && cp res/package.mjs.json dist/mjs/package.json",
     "build:cjs": "npx tsc --project tsconfig.cjs.json && cp res/package.cjs.json dist/cjs/package.json",
-    "build:iife": "rm -rf dist/iife && npx tsc --project tsconfig.iife.json && rollup dist/iife/index.js --file dist/iife/index.bundle.js --format iife --name Spaces -e ably -g ably:Ably",
+    "build:iife": "rm -rf dist/iife && npx tsc --project tsconfig.iife.json && rollup -c",
     "prepare": "husky install"
   },
   "exports": {
@@ -49,6 +49,7 @@
     "husky": "^8.0.0",
     "mock-socket": "^9.1.5",
     "prettier": "^2.8.3",
+    "rollup": "^3.28.0",
     "typescript": "^4.9.5",
     "vitest": "^0.29.8"
   },
diff --git a/rollup.config.mjs b/rollup.config.mjs
new file mode 100644
index 00000000..a0381498
--- /dev/null
+++ b/rollup.config.mjs
@@ -0,0 +1,13 @@
+export default {
+  input: 'dist/iife/index.js',
+  output: {
+    format: 'iife',
+    name: 'Spaces',
+    file: 'dist/iife/index.bundle.js',
+    globals: {
+      ably: 'Ably',
+      nanoid: 'nanoid',
+    },
+  },
+  external: ['ably', 'nanoid'],
+};
diff --git a/src/CursorBatching.ts b/src/CursorBatching.ts
index 5d0ecc79..08851e06 100644
--- a/src/CursorBatching.ts
+++ b/src/CursorBatching.ts
@@ -1,6 +1,6 @@
 import { Types } from 'ably';
 
-import { CURSOR_UPDATE } from './Cursors.js';
+import { CURSOR_UPDATE } from './CursorConstants.js';
 import type { CursorUpdate } from './types.js';
 import type { CursorsOptions } from './types.js';
 
@@ -44,14 +44,14 @@ export default class CursorBatching {
     this.outgoingBuffers.push(value);
   }
 
-  private async publishFromBuffer(channel, eventName: string) {
+  private async publishFromBuffer(channel: Types.RealtimeChannelPromise, eventName: string) {
     if (!this.isRunning) {
       this.isRunning = true;
       await this.batchToChannel(channel, eventName);
     }
   }
 
-  private async batchToChannel(channel, eventName: string) {
+  private async batchToChannel(channel: Types.RealtimeChannelPromise, eventName: string) {
     if (!this.hasMovement) {
       this.isRunning = false;
       return;
diff --git a/src/CursorConstants.ts b/src/CursorConstants.ts
new file mode 100644
index 00000000..c08e3333
--- /dev/null
+++ b/src/CursorConstants.ts
@@ -0,0 +1 @@
+export const CURSOR_UPDATE = 'cursorUpdate';
diff --git a/src/CursorDispensing.ts b/src/CursorDispensing.ts
index d73905d2..ae8df5c9 100644
--- a/src/CursorDispensing.ts
+++ b/src/CursorDispensing.ts
@@ -7,13 +7,8 @@ export default class CursorDispensing {
   private buffer: Record<string, CursorUpdate[]> = {};
   private handlerRunning: boolean = false;
   private timerIds: ReturnType<typeof setTimeout>[] = [];
-  private emitCursorUpdate: (update: CursorUpdate) => void;
-  private getCurrentBatchTime: () => number;
 
-  constructor(emitCursorUpdate, getCurrentBatchTime) {
-    this.emitCursorUpdate = emitCursorUpdate;
-    this.getCurrentBatchTime = getCurrentBatchTime;
-  }
+  constructor(private emitCursorUpdate: (update: CursorUpdate) => void, private getCurrentBatchTime: () => number) {}
 
   emitFromBatch(batchDispenseInterval: number) {
     if (!this.bufferHaveData()) {
@@ -66,7 +61,7 @@ export default class CursorDispensing {
   }
 
   processBatch(message: RealtimeMessage) {
-    const updates = message.data || [];
+    const updates: CursorUpdate[] = message.data || [];
 
     updates.forEach((update) => {
       const enhancedMsg = {
diff --git a/src/Cursors.test.ts b/src/Cursors.test.ts
index c837e070..d04f7626 100644
--- a/src/Cursors.test.ts
+++ b/src/Cursors.test.ts
@@ -2,7 +2,8 @@ import { it, describe, expect, vi, beforeEach, vitest, afterEach } from 'vitest'
 import { Realtime, Types } from 'ably/promises';
 
 import Space from './Space.js';
-import Cursors, { CURSOR_UPDATE } from './Cursors.js';
+import Cursors from './Cursors.js';
+import { CURSOR_UPDATE } from './CursorConstants.js';
 import { createPresenceMessage } from './utilities/test/fakes.js';
 import CursorBatching from './CursorBatching.js';
 import CursorDispensing from './CursorDispensing.js';
diff --git a/src/Cursors.ts b/src/Cursors.ts
index f95ad8d1..98b7aeba 100644
--- a/src/Cursors.ts
+++ b/src/Cursors.ts
@@ -10,6 +10,7 @@ import EventEmitter, {
   type EventListener,
 } from './utilities/EventEmitter.js';
 import CursorHistory from './CursorHistory.js';
+import { CURSOR_UPDATE } from './CursorConstants.js';
 
 import type { CursorsOptions, CursorUpdate } from './types.js';
 import type { RealtimeMessage } from './utilities/types.js';
@@ -18,22 +19,6 @@ type CursorsEventMap = {
   cursorsUpdate: CursorUpdate;
 };
 
-export const CURSOR_UPDATE = 'cursorUpdate';
-
-const emitterHasListeners = (emitter) => {
-  const flattenEvents = (obj) =>
-    Object.entries(obj)
-      .map((_, v) => v)
-      .flat();
-
-  return (
-    emitter.any.length > 0 ||
-    emitter.anyOnce.length > 0 ||
-    flattenEvents(emitter.events).length > 0 ||
-    flattenEvents(emitter.eventsOnce).length > 0
-  );
-};
-
 export default class Cursors extends EventEmitter<CursorsEventMap> {
   private readonly cursorBatching: CursorBatching;
   private readonly cursorDispensing: CursorDispensing;
@@ -92,9 +77,29 @@ export default class Cursors extends EventEmitter<CursorsEventMap> {
 
   private isUnsubscribed() {
     const channel = this.getChannel();
-    return !emitterHasListeners(channel['subscriptions']);
+
+    interface ChannelWithSubscriptions extends Types.RealtimeChannelPromise {
+      subscriptions: EventEmitter<{}>;
+    }
+
+    const subscriptions = (channel as ChannelWithSubscriptions).subscriptions;
+    return !this.emitterHasListeners(subscriptions);
   }
 
+  private emitterHasListeners = (emitter: EventEmitter<{}>) => {
+    const flattenEvents = (obj: Record<string, Function[]>) =>
+      Object.entries(obj)
+        .map((_, v) => v)
+        .flat();
+
+    return (
+      emitter.any.length > 0 ||
+      emitter.anyOnce.length > 0 ||
+      flattenEvents(emitter.events).length > 0 ||
+      flattenEvents(emitter.eventsOnce).length > 0
+    );
+  };
+
   subscribe<K extends EventKey<CursorsEventMap>>(
     listenerOrEvents?: K | K[] | EventListener<CursorsEventMap[K]>,
     listener?: EventListener<CursorsEventMap[K]>,
@@ -136,7 +141,7 @@ export default class Cursors extends EventEmitter<CursorsEventMap> {
       }
     }
 
-    const hasListeners = emitterHasListeners(this);
+    const hasListeners = this.emitterHasListeners(this);
 
     if (!hasListeners) {
       const channel = this.getChannel();
diff --git a/src/Locations.ts b/src/Locations.ts
index ea4d55a7..41eec662 100644
--- a/src/Locations.ts
+++ b/src/Locations.ts
@@ -117,14 +117,14 @@ export default class Locations extends EventEmitter<LocationsEventMap> {
     return this.space.members
       .getAll()
       .filter((member) => member.connectionId !== self?.connectionId)
-      .reduce((acc, member) => {
+      .reduce((acc: Record<string, unknown>, member: SpaceMember) => {
         acc[member.connectionId] = member.location;
         return acc;
       }, {});
   }
 
   getAll(): Record<string, unknown> {
-    return this.space.members.getAll().reduce((acc, member) => {
+    return this.space.members.getAll().reduce((acc: Record<string, unknown>, member: SpaceMember) => {
       acc[member.connectionId] = member.location;
       return acc;
     }, {});
diff --git a/src/Space.ts b/src/Space.ts
index 1233f12a..c1deaeda 100644
--- a/src/Space.ts
+++ b/src/Space.ts
@@ -92,7 +92,11 @@ class Space extends EventEmitter<SpaceEventsMap> {
     return new Promise((resolve) => {
       const presence = this.channel.presence;
 
-      presence['subscriptions'].once('enter', async () => {
+      interface PresenceWithSubscriptions extends Types.RealtimePresencePromise {
+        subscriptions: EventEmitter<{ enter: [unknown] }>;
+      }
+
+      (presence as PresenceWithSubscriptions).subscriptions.once('enter', async () => {
         const presenceMessages = await presence.get();
         const members = this.members.mapPresenceMembersToSpaceMembers(presenceMessages);
 
diff --git a/src/Spaces.test.ts b/src/Spaces.test.ts
index 3e859ca2..f204abab 100644
--- a/src/Spaces.test.ts
+++ b/src/Spaces.test.ts
@@ -1,17 +1,17 @@
 import { it, describe, expect, expectTypeOf, vi, beforeEach } from 'vitest';
 import { Realtime, Types } from 'ably/promises';
 
-import Spaces from './Spaces.js';
+import Spaces, { type ClientWithOptions } from './Spaces.js';
 
 interface SpacesTestContext {
-  client: Types.RealtimePromise;
+  client: ClientWithOptions;
 }
 
 vi.mock('ably/promises');
 
 describe('Spaces', () => {
   beforeEach<SpacesTestContext>((context) => {
-    context.client = new Realtime({ key: 'asd' });
+    context.client = new Realtime({ key: 'asd' }) as ClientWithOptions;
   });
 
   it<SpacesTestContext>('expects the injected client to be of the type RealtimePromise', ({ client }) => {
@@ -32,14 +32,18 @@ describe('Spaces', () => {
 
   it<SpacesTestContext>('applies the agent header to an existing SDK instance', ({ client }) => {
     const spaces = new Spaces(client);
-    expect(client['options'].agents).toEqual({ 'ably-spaces': spaces.version, 'space-custom-client': true });
+    expect(client.options.agents).toEqual({
+      'ably-spaces': spaces.version,
+      'space-custom-client': true,
+    });
   });
 
   it<SpacesTestContext>('extend the agents array when it already exists', ({ client }) => {
-    client['options']['agents'] = { 'some-client': '1.2.3' };
+    (client as ClientWithOptions).options.agents = { 'some-client': '1.2.3' };
     const spaces = new Spaces(client);
+    const ablyClient = spaces.ably as ClientWithOptions;
 
-    expect(spaces.ably['options'].agents).toEqual({
+    expect(ablyClient.options.agents).toEqual({
       'some-client': '1.2.3',
       'ably-spaces': spaces.version,
       'space-custom-client': true,
diff --git a/src/Spaces.ts b/src/Spaces.ts
index 1a8ef033..56acfea5 100644
--- a/src/Spaces.ts
+++ b/src/Spaces.ts
@@ -5,6 +5,12 @@ import Space from './Space.js';
 import type { SpaceOptions } from './types.js';
 import type { Subset } from './utilities/types.js';
 
+export interface ClientWithOptions extends Types.RealtimePromise {
+  options: {
+    agents?: Record<string, string | boolean>;
+  };
+}
+
 class Spaces {
   private spaces: Record<string, Space> = {};
   ably: Types.RealtimePromise;
@@ -13,7 +19,7 @@ class Spaces {
 
   constructor(client: Types.RealtimePromise) {
     this.ably = client;
-    this.addAgent(this.ably['options']);
+    this.addAgent((this.ably as ClientWithOptions)['options']);
     this.ably.time();
   }
 
diff --git a/src/utilities/EventEmitter.test.ts b/src/utilities/EventEmitter.test.ts
index e96650ac..aa4c87f6 100644
--- a/src/utilities/EventEmitter.test.ts
+++ b/src/utilities/EventEmitter.test.ts
@@ -98,14 +98,14 @@ describe('EventEmitter', () => {
     it('adds a listener to the "any" set of event listeners', (context) => {
       context.eventEmitter['on'](context.spy);
       expect(context.eventEmitter['any']).toStrictEqual([context.spy]);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledOnce();
     });
 
     it('adds a listener to a provided field of an event listener', (context) => {
       context.eventEmitter['on']('myEvent', context.spy);
       expect(context.eventEmitter['events']['myEvent']).toStrictEqual([context.spy]);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledOnce();
     });
 
@@ -114,11 +114,11 @@ describe('EventEmitter', () => {
       expect(context.eventEmitter['events']['myEvent']).toStrictEqual([context.spy]);
       expect(context.eventEmitter['events']['myOtherEvent']).toStrictEqual([context.spy]);
       expect(context.eventEmitter['events']['myThirdEvent']).toStrictEqual([context.spy]);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledTimes(1);
-      context.eventEmitter['emit']('myOtherEvent');
+      context.eventEmitter['emit']('myOtherEvent', '');
       expect(context.spy).toHaveBeenCalledTimes(2);
-      context.eventEmitter['emit']('myThirdEvent');
+      context.eventEmitter['emit']('myThirdEvent', '');
       expect(context.spy).toHaveBeenCalledTimes(3);
     });
   });
@@ -148,7 +148,7 @@ describe('EventEmitter', () => {
       expect(context.eventEmitter['anyOnce']).toStrictEqual([]);
       expect(context.eventEmitter['events']).toStrictEqual(Object.create(null));
       expect(context.eventEmitter['eventsOnce']).toStrictEqual(Object.create(null));
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).not.toHaveBeenCalled();
     });
 
@@ -158,7 +158,7 @@ describe('EventEmitter', () => {
       expect(context.eventEmitter['anyOnce']).toStrictEqual([altListener]);
       expect(context.eventEmitter['events']['myEvent']).not.toContain(context.spy);
       expect(context.eventEmitter['eventsOnce']['myEvent']).not.toContain(context.spy);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).not.toHaveBeenCalled();
     });
 
@@ -168,9 +168,9 @@ describe('EventEmitter', () => {
       expect(context.eventEmitter['anyOnce']).toStrictEqual([context.spy, altListener]);
       expect(context.eventEmitter['events']['myEvent']).not.toContain(context.spy);
       expect(context.eventEmitter['events']['myOtherEvent']).toContain(context.spy);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledTimes(2);
-      context.eventEmitter['emit']('myOtherEvent');
+      context.eventEmitter['emit']('myOtherEvent', '');
       expect(context.spy).toHaveBeenCalledTimes(3);
     });
 
@@ -182,11 +182,11 @@ describe('EventEmitter', () => {
       expect(eventEmitter['events']['myEvent']).toBe(undefined);
       expect(eventEmitter['events']['myOtherEvent']).toBe(undefined);
       expect(eventEmitter['events']['myThirdEvent']).toContain(specificListener);
-      eventEmitter['emit']('myEvent');
-      eventEmitter['emit']('myOtherEvent');
+      eventEmitter['emit']('myEvent', '');
+      eventEmitter['emit']('myOtherEvent', '');
       expect(specificListener).not.toHaveBeenCalled();
       expect(eventEmitter['events']['myThirdEvent']).toContain(specificListener);
-      eventEmitter['emit']('myThirdEvent');
+      eventEmitter['emit']('myThirdEvent', '');
       expect(specificListener).toHaveBeenCalledOnce();
     });
 
@@ -241,17 +241,17 @@ describe('EventEmitter', () => {
     it('adds a listener to anyOnce on calling `once` with a listener', (context) => {
       context.eventEmitter['once'](context.spy);
       expect(context.eventEmitter['anyOnce']).toHaveLength(1);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledOnce();
-      context.eventEmitter['emit']('myOtherEvent');
+      context.eventEmitter['emit']('myOtherEvent', '');
     });
 
     it('adds a listener to an eventOnce on calling `once` with a listener and event name', (context) => {
       context.eventEmitter['once']('myEvent', context.spy);
       expect(context.eventEmitter['eventsOnce']['myEvent']).toHaveLength(1);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledOnce();
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledOnce();
     });
 
@@ -260,7 +260,7 @@ describe('EventEmitter', () => {
       expect(context.eventEmitter['eventsOnce']['myEvent']).toHaveLength(1);
       expect(context.eventEmitter['eventsOnce']['myOtherEvent']).toHaveLength(1);
       expect(context.eventEmitter['eventsOnce']['myThirdEvent']).toHaveLength(1);
-      expect(context.eventEmitter['emit']('myEvent'));
+      expect(context.eventEmitter['emit']('myEvent', ''));
       expect(context.eventEmitter['eventsOnce']['myEvent']).toBe(undefined);
       expect(context.eventEmitter['eventsOnce']['myOtherEvent']).toBe(undefined);
       expect(context.eventEmitter['eventsOnce']['myThirdEvent']).toBe(undefined);
@@ -279,7 +279,7 @@ describe('EventEmitter', () => {
       context.eventEmitter['on']('myEvent', context.spy);
       expect(context.eventEmitter['listeners']('myEvent')).toContain(context.spy);
       expect(context.spy).not.toHaveBeenCalled();
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.spy).toHaveBeenCalledOnce();
       // anyOnce must also be emptied
       expect(context.eventEmitter['anyOnce']).toStrictEqual([]);
@@ -287,7 +287,7 @@ describe('EventEmitter', () => {
 
     it('emits any events in anyOnce on emitting specific events', (context) => {
       context.eventEmitter['on']('myEvent', context.spy);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.eventEmitter['anyOnce']).toStrictEqual([]);
       expect(context.spy).toHaveBeenCalledOnce();
     });
@@ -295,7 +295,7 @@ describe('EventEmitter', () => {
     it('emits an event and removes it on being called for a once operation', (context) => {
       context.eventEmitter['once']('myEvent', context.spy);
       expect(context.eventEmitter['listeners']('myEvent')).toContain(context.spy);
-      context.eventEmitter['emit']('myEvent');
+      context.eventEmitter['emit']('myEvent', '');
       expect(context.eventEmitter['listeners']('myEvent')).toBe(null);
       expect(context.eventEmitter['anyOnce']).toStrictEqual([]);
       expect(context.spy).toHaveBeenCalledOnce();
diff --git a/src/utilities/EventEmitter.ts b/src/utilities/EventEmitter.ts
index 0359f224..358b74c6 100644
--- a/src/utilities/EventEmitter.ts
+++ b/src/utilities/EventEmitter.ts
@@ -23,13 +23,13 @@ export function removeListener(
   eventFilter?: string,
 ) {
   let listeners: Function[] | Record<string, Function[]>;
-  let index;
-  let eventName;
+  let index: number;
+  let eventName: string;
 
   for (let targetListenersIndex = 0; targetListenersIndex < targetListeners.length; targetListenersIndex++) {
     listeners = targetListeners[targetListenersIndex];
 
-    if (eventFilter) {
+    if (isString(eventFilter) && isObject(listeners)) {
       listeners = listeners[eventFilter];
     }
 
@@ -39,8 +39,9 @@ export function removeListener(
       }
       /* If events object has an event name key with no listeners then
 				 remove the key to stop the list growing indefinitely */
-      if (eventFilter && listeners.length === 0) {
-        delete targetListeners[targetListenersIndex][eventFilter];
+      const parentCollection = targetListeners[targetListenersIndex];
+      if (eventFilter && listeners.length === 0 && isObject(parentCollection)) {
+        delete parentCollection[eventFilter];
       }
     } else if (isObject(listeners)) {
       for (eventName in listeners) {
@@ -58,21 +59,21 @@ export function inspect(args: unknown): string {
 }
 
 export class InvalidArgumentError extends Error {
-  constructor(...args) {
+  constructor(...args: [string | undefined]) {
     super(...args);
   }
 }
 
-export type EventMap = Record<string, any>;
+export type EventMap = Record<string, unknown>;
 // extract all the keys of an event map and use them as a type
 export type EventKey<T extends EventMap> = string & keyof T;
 export type EventListener<T> = (params: T) => void;
 
 export default class EventEmitter<T extends EventMap> {
-  protected any: Array<Function>;
-  protected events: Record<string, Function[]>;
-  protected anyOnce: Array<Function>;
-  protected eventsOnce: Record<string, Function[]>;
+  any: Array<Function>;
+  events: Record<string, Function[]>;
+  anyOnce: Array<Function>;
+  eventsOnce: Record<string, Function[]>;
 
   constructor() {
     this.any = [];
@@ -86,10 +87,7 @@ export default class EventEmitter<T extends EventMap> {
    * @param listenerOrEvents (optional) the name of the event to listen to or the listener to be called.
    * @param listener (optional) the listener to be called.
    */
-  protected on<K extends EventKey<T>>(
-    listenerOrEvents?: K | K[] | EventListener<T[K]>,
-    listener?: EventListener<T[K]>,
-  ): void {
+  on<K extends EventKey<T>>(listenerOrEvents?: K | K[] | EventListener<T[K]>, listener?: EventListener<T[K]>): void {
     // .on(() => {})
     if (isFunction(listenerOrEvents)) {
       this.any.push(listenerOrEvents);
@@ -120,10 +118,7 @@ export default class EventEmitter<T extends EventMap> {
    * the listener is treated as an 'any' listener.
    * @param listener (optional) the listener to remove. If not supplied, all listeners are removed.
    */
-  protected off<K extends EventKey<T>>(
-    listenerOrEvents?: K | K[] | EventListener<T[K]>,
-    listener?: EventListener<T[K]>,
-  ): void {
+  off<K extends EventKey<T>>(listenerOrEvents?: K | K[] | EventListener<T[K]>, listener?: EventListener<T[K]>): void {
     // .off()
     // don't use arguments.length === 0 here as don't won't handle
     // cases like .off(undefined) which is a valid call
@@ -178,7 +173,7 @@ export default class EventEmitter<T extends EventMap> {
    * @param event (optional) the name of the event, or none for 'any'
    * @return array of events, or null if none
    */
-  protected listeners<K extends EventKey<T>>(event: K): Function[] | null {
+  listeners<K extends EventKey<T>>(event: K): Function[] | null {
     if (event) {
       const listeners = [...(this.events[event] ?? [])];
 
@@ -195,9 +190,9 @@ export default class EventEmitter<T extends EventMap> {
   /**
    * Emit an event
    * @param event the event name
-   * @param args the arguments to pass to the listener
+   * @param arg the arguments to pass to the listener
    */
-  emit<K extends EventKey<T>>(event: K, ...args: unknown[] /* , args... */) {
+  emit<K extends EventKey<T>>(event: K, arg: T[K]) {
     const eventThis = { event };
     const listeners: Function[] = [];
 
@@ -222,7 +217,7 @@ export default class EventEmitter<T extends EventMap> {
     }
 
     listeners.forEach(function (listener) {
-      callListener(eventThis, listener, args);
+      callListener(eventThis, listener, [arg]);
     });
   }
 
@@ -231,7 +226,7 @@ export default class EventEmitter<T extends EventMap> {
    * @param listenerOrEvents (optional) the name of the event to listen to
    * @param listener (optional) the listener to be called
    */
-  protected once<K extends EventKey<T>>(
+  once<K extends EventKey<T>>(
     listenerOrEvents: K | K[] | EventListener<T[K]>,
     listener?: EventListener<T[K]>,
   ): void | Promise<any> {
@@ -245,12 +240,14 @@ export default class EventEmitter<T extends EventMap> {
     // .once(["eventName"], () => {})
     if (isArray(listenerOrEvents) && isFunction(listener)) {
       const self = this;
+
       listenerOrEvents.forEach(function (eventName) {
-        const listenerWrapper = function (listenerThis: any) {
-          const innerArgs = Array.prototype.slice.call(arguments);
+        const listenerWrapper: EventListener<T[K]> = function (this: EventListener<T[K]>, listenerThis) {
+          const innerArgs = Array.prototype.slice.call(arguments) as [params: T[K]];
           listenerOrEvents.forEach((eventName) => {
             self.off(eventName, this);
           });
+
           listener.apply(listenerThis, innerArgs);
         };
         self.once(eventName, listenerWrapper);
@@ -277,12 +274,7 @@ export default class EventEmitter<T extends EventMap> {
    * @param listener the listener to be called
    * @param listenerArgs
    */
-  protected whenState(
-    targetState: string,
-    currentState: string,
-    listener: EventListener<T>,
-    ...listenerArgs: unknown[]
-  ) {
+  whenState(targetState: string, currentState: string, listener: EventListener<T[string]>, ...listenerArgs: unknown[]) {
     const eventThis = { event: targetState };
 
     if (typeof targetState !== 'string' || typeof currentState !== 'string') {
diff --git a/src/utilities/math.ts b/src/utilities/math.ts
index 33bc7d7d..0e6c2a69 100644
--- a/src/utilities/math.ts
+++ b/src/utilities/math.ts
@@ -1,4 +1,4 @@
-function clamp(num, min, max) {
+function clamp(num: number, min: number, max: number) {
   return Math.min(Math.max(num, min), max);
 }
 
diff --git a/src/utilities/test/fakes.ts b/src/utilities/test/fakes.ts
index 49e5c2a1..696b99d3 100644
--- a/src/utilities/test/fakes.ts
+++ b/src/utilities/test/fakes.ts
@@ -1,10 +1,14 @@
+import { Types } from 'ably';
+
+import Space from '../../Space.js';
+
 import type { SpaceMember } from '../../types.js';
 import type { PresenceMember } from '../../utilities/types.js';
 
 // import { nanoidId } from '../../../__mocks__/nanoid/index.js';
 const nanoidId = 'NanoidID';
 
-const enterPresenceMessage = {
+const enterPresenceMessage: Types.PresenceMessage = {
   clientId: '1',
   data: {
     profileUpdate: {
@@ -24,17 +28,23 @@ const enterPresenceMessage = {
   timestamp: 1,
 };
 
-const updatePresenceMessage = {
+const updatePresenceMessage: Types.PresenceMessage = {
   ...enterPresenceMessage,
   action: 'update',
 };
 
-const leavePresenceMessage = {
+const leavePresenceMessage: Types.PresenceMessage = {
   ...enterPresenceMessage,
   action: 'leave',
 };
 
-const createPresenceMessage = (type, override?) => {
+type MessageMap = {
+  enter: typeof enterPresenceMessage;
+  update: typeof updatePresenceMessage;
+  leave: typeof leavePresenceMessage;
+};
+
+const createPresenceMessage = <T extends keyof MessageMap>(type: T, override?: Partial<MessageMap[T]>) => {
   switch (type) {
     case 'enter':
       return { ...enterPresenceMessage, ...override };
@@ -47,7 +57,7 @@ const createPresenceMessage = (type, override?) => {
   }
 };
 
-const createPresenceEvent = (space, type, override?) => {
+const createPresenceEvent = <T extends keyof MessageMap>(space: Space, type: T, override?: Partial<MessageMap[T]>) => {
   space['onPresenceUpdate'](createPresenceMessage(type, override));
 };
 
diff --git a/tsconfig.base.json b/tsconfig.base.json
index b2d4f476..ca0aa81c 100644
--- a/tsconfig.base.json
+++ b/tsconfig.base.json
@@ -5,7 +5,9 @@
     "target": "es6",
     "rootDir": "./src",
     "sourceMap": true,
-    "strict": false,
+    "strict": true,
+    "alwaysStrict": true,
+    "noImplicitThis": true,
     "esModuleInterop": true,
     "declaration": true,
     "moduleResolution": "node",