diff --git a/config/webpack.library.js b/config/webpack.library.js
index 4c3ff7b3..24c47e25 100644
--- a/config/webpack.library.js
+++ b/config/webpack.library.js
@@ -55,7 +55,7 @@ module.exports = {
     maxAssetSize: 9000000
   },
   entry: {
-    "bundle.min": "./js/webamp.js",
+    "bundle.min": "./js/webamp.ts",
     "lazy-bundle.min": "./js/webampLazy.tsx"
   },
   output: {
diff --git a/demo/config/webpack.common.js b/demo/config/webpack.common.js
index edada5a1..b56df75b 100644
--- a/demo/config/webpack.common.js
+++ b/demo/config/webpack.common.js
@@ -93,7 +93,7 @@ module.exports = {
     maxAssetSize: 7000000
   },
   entry: {
-    webamp: ["./js/index.js"]
+    webamp: ["./js/index.tsx"]
   },
   context: path.resolve(__dirname, "../"),
   output: {
diff --git a/demo/js/index.js b/demo/js/index.tsx
similarity index 91%
rename from demo/js/index.js
rename to demo/js/index.tsx
index 0680d16d..eb6ad7e5 100644
--- a/demo/js/index.js
+++ b/demo/js/index.tsx
@@ -5,6 +5,8 @@ import React from "react";
 import ReactDOM from "react-dom";
 import createMiddleware from "raven-for-redux";
 import isButterchurnSupported from "butterchurn/lib/isSupported.min";
+import JSZip from "jszip";
+// @ts-ignore
 import base from "../../skins/base-2.91-png.wsz";
 import { WINDOWS } from "../../js/constants";
 import * as Selectors from "../../js/selectors";
@@ -40,6 +42,9 @@ import WebampIcon from "./WebampIcon";
 import enableMediaSession from "./mediaSession";
 import screenshotInitialState from "./screenshotInitialState";
 
+declare const SENTRY_DSN: string | undefined;
+declare const COMMITHASH: string | undefined;
+
 const DEFAULT_DOCUMENT_TITLE = document.title;
 
 const NOISY_ACTION_TYPES = new Set([
@@ -53,7 +58,7 @@ const NOISY_ACTION_TYPES = new Set([
 
 const MIN_MILKDROP_WIDTH = 725;
 
-let screenshot = false;
+let screenshot = null;
 let clearState = false;
 let useState = false;
 let skinUrl = configSkinUrl;
@@ -112,9 +117,13 @@ window.addEventListener("beforeinstallprompt", e => {
 });
 
 Raven.context(async () => {
+  // @ts-ignore
   window.Raven = Raven;
   if (screenshot) {
-    document.getElementsByClassName("about")[0].style.visibility = "hidden";
+    const aboutNode = document.getElementsByClassName("about")[0];
+    if (aboutNode != null) {
+      (aboutNode as HTMLElement).style.visibility = "hidden";
+    }
   }
   if (!WebampLazy.browserIsSupported()) {
     document.getElementById("browser-compatibility").style.display = "block";
@@ -172,8 +181,8 @@ Raven.context(async () => {
     availableSkins,
     filePickers: [dropboxFilePicker],
     enableHotkeys: true,
-    requireJSZip: () =>
-      import(/* webpackChunkName: "jszip" */ "jszip/dist/jszip"),
+    requireJSZip: async () =>
+      (await import(/* webpackChunkName: "jszip" */ "jszip")).default,
     requireMusicMetadata: () =>
       import(/* webpackChunkName: "music-metadata-browser" */ "music-metadata-browser/dist/index"),
     __enableMediaLibrary: library,
@@ -231,12 +240,15 @@ Raven.context(async () => {
   fileInput.style.display = "none";
   fileInput.type = "file";
   fileInput.value = null;
-  fileInput.addEventListener("change", e => {
-    webamp.store.dispatch(loadFilesFromReferences(e.target.files));
+  fileInput.addEventListener("change", (e: Event) => {
+    webamp.store.dispatch(
+      loadFilesFromReferences((e.target as HTMLInputElement).files)
+    );
   });
   document.body.appendChild(fileInput);
 
   // Expose webamp instance for debugging and integration tests.
+  // @ts-ignore
   window.__webamp = webamp;
 
   await bindToIndexedDB(webamp, clearState, useState);
diff --git a/js/actionCreators/files.ts b/js/actionCreators/files.ts
index 1e7d9502..99e60bb6 100644
--- a/js/actionCreators/files.ts
+++ b/js/actionCreators/files.ts
@@ -1,5 +1,6 @@
 import { parser, creator } from "winamp-eqf";
 import { BANDS, LOAD_STYLE } from "../constants";
+import JSZip from "jszip";
 
 import * as Utils from "../utils";
 
@@ -88,7 +89,7 @@ export function setSkinFromArrayBuffer(
       return;
     }
     dispatch({ type: LOADING });
-    let JSZip;
+    let JSZip: JSZip;
     try {
       JSZip = await requireJSZip();
     } catch (e) {
diff --git a/js/types.ts b/js/types.ts
index a5c948a1..b53deaf2 100644
--- a/js/types.ts
+++ b/js/types.ts
@@ -1,3 +1,4 @@
+import JSZip from "jszip";
 import { PlaylistState } from "./reducers/playlist";
 import { SettingsState } from "./reducers/settings";
 import { UserInputState } from "./reducers/userInput";
@@ -308,7 +309,7 @@ export type Action =
     }
   | {
       type: "SET_DUMMY_VIZ_DATA";
-      data: null;
+      data: DummyVizData;
     }
   | {
       type: "SET_BAND_VALUE";
@@ -641,7 +642,7 @@ export interface IMusicMetadataBrowserApi {
 }
 
 export interface Extras {
-  requireJSZip(): Promise<never>;
+  requireJSZip(): Promise<JSZip>;
   requireMusicMetadata(): Promise<IMusicMetadataBrowserApi>;
   convertPreset: ((file: File) => Promise<Object>) | null;
   handleTrackDropEvent?: (
diff --git a/js/webamp.js b/js/webamp.js
deleted file mode 100644
index c1027ec9..00000000
--- a/js/webamp.js
+++ /dev/null
@@ -1,15 +0,0 @@
-import JSZip from "jszip";
-import * as musicMetadataBrowser from "music-metadata-browser";
-import WebampLazy from "./webampLazy";
-
-class Winamp extends WebampLazy {
-  constructor(options) {
-    super({
-      ...options,
-      requireJSZip: () => JSZip,
-      requireMusicMetadata: () => musicMetadataBrowser
-    });
-  }
-}
-
-export default Winamp;
diff --git a/js/webamp.ts b/js/webamp.ts
new file mode 100644
index 00000000..ecae7a36
--- /dev/null
+++ b/js/webamp.ts
@@ -0,0 +1,15 @@
+import JSZip from "jszip";
+import * as musicMetadataBrowser from "music-metadata-browser";
+import WebampLazy, { Options } from "./webampLazy";
+
+class Winamp extends WebampLazy {
+  constructor(options: Options) {
+    super({
+      ...options,
+      requireJSZip: () => Promise.resolve(JSZip),
+      requireMusicMetadata: () => Promise.resolve(musicMetadataBrowser)
+    });
+  }
+}
+
+export default Winamp;
diff --git a/js/webampLazy.tsx b/js/webampLazy.tsx
index a94209b9..7e702db4 100644
--- a/js/webampLazy.tsx
+++ b/js/webampLazy.tsx
@@ -1,6 +1,7 @@
 import React from "react";
 import ReactDOM from "react-dom";
 import { Provider } from "react-redux";
+import JSZip from "jszip";
 
 import {
   Store,
@@ -39,8 +40,9 @@ import Emitter from "./emitter";
 import "../css/base-skin.css";
 import { SerializedStateV1 } from "./serializedStates/v1Types";
 import Disposable from "./Disposable";
+import { DeepPartial } from "redux";
 
-interface Options {
+export interface Options {
   /**
    * An object representing the initial skin to use.
    *
@@ -104,26 +106,26 @@ interface Options {
       requiresNetwork: boolean;
     }
   ];
-  zIndex: number;
+  zIndex?: number;
 }
 
 interface PrivateOptions {
   avaliableSkins?: { url: string; name: string }[]; // Old misspelled name
-  requireJSZip(): Promise<never>; // TODO: Type JSZip
+  requireJSZip(): Promise<JSZip>; // TODO: Type JSZip
   requireMusicMetadata(): Promise<any>; // TODO: Type musicmetadata
   handleTrackDropEvent?: (
     e: React.DragEvent<HTMLDivElement>
   ) => Track[] | null | Promise<Track[] | null>;
-  __initialState?: AppState;
+  __initialState?: DeepPartial<AppState>;
   __customMiddlewares?: Middleware[];
   __enableMediaLibrary?: boolean;
-  __initialWindowLayout: {
+  __initialWindowLayout?: {
     [windowId: string]: {
       size: null | [number, number];
       position: WindowPosition;
     };
   };
-  __butterchurnOptions: ButterchurnOptions;
+  __butterchurnOptions?: ButterchurnOptions;
 }
 
 // Return a promise that resolves when the store matches a predicate.
diff --git a/package.json b/package.json
index 5f2614fe..3ddb21a2 100644
--- a/package.json
+++ b/package.json
@@ -64,6 +64,7 @@
     "@babel/runtime": "^7.0.0",
     "@types/classnames": "^2.2.6",
     "@types/fscreen": "^1.0.1",
+    "@types/jszip": "^3.1.5",
     "@types/invariant": "^2.2.29",
     "@types/jest": "^23.3.2",
     "@types/lodash": "^4.14.116",
diff --git a/yarn.lock b/yarn.lock
index 65b56dc9..2f896e66 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -726,6 +726,12 @@
   version "23.3.2"
   resolved "https://registry.yarnpkg.com/@types/jest/-/jest-23.3.2.tgz#07b90f6adf75d42c34230c026a2529e56c249dbb"
 
+"@types/jszip@^3.1.5":
+  version "3.1.5"
+  resolved "https://registry.yarnpkg.com/@types/jszip/-/jszip-3.1.5.tgz#664b424b15aadf0489e871d319f4b18ddc6e24ea"
+  dependencies:
+    "@types/node" "*"
+
 "@types/lodash-es@^4.17.1":
   version "4.17.1"
   resolved "https://registry.yarnpkg.com/@types/lodash-es/-/lodash-es-4.17.1.tgz#56745e5411558362aeca31def918f88f725dd29d"