diff --git a/cli/js/compiler.ts b/cli/js/compiler.ts
index c0f9c0a1ed..79b9fdaf6f 100644
--- a/cli/js/compiler.ts
+++ b/cli/js/compiler.ts
@@ -32,9 +32,10 @@ import { fromTypeScriptDiagnostic } from "./diagnostics_util.ts";
 import * as os from "./os.ts";
 import { assert } from "./util.ts";
 import * as util from "./util.ts";
-import { window as self } from "./window.ts";
 import { postMessage, workerClose, workerMain } from "./workers.ts";
 
+const self = globalThis;
+
 interface CompilerRequestCompile {
   type: CompilerRequestType.Compile;
   rootNames: string[];
diff --git a/cli/js/core.ts b/cli/js/core.ts
index 5a60b6f860..5a0d952254 100644
--- a/cli/js/core.ts
+++ b/cli/js/core.ts
@@ -1,6 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { window } from "./window.ts";
 
 // This allows us to access core in API even if we
 // dispose window.Deno
-export const core = window.Deno.core as DenoCore;
+export const core = globalThis.Deno.core as DenoCore;
diff --git a/cli/js/event_target.ts b/cli/js/event_target.ts
index f6cb96aa2a..495c8a0429 100644
--- a/cli/js/event_target.ts
+++ b/cli/js/event_target.ts
@@ -10,7 +10,6 @@ import {
   isSlotable,
   retarget
 } from "./dom_util.ts";
-import { window } from "./window.ts";
 
 // https://dom.spec.whatwg.org/#get-the-parent
 // Note: Nodes, shadow roots, and documents override this algorithm so we set it to null.
@@ -40,7 +39,7 @@ export class EventTarget implements domTypes.EventTarget {
     callback: (event: domTypes.Event) => void | null,
     options?: domTypes.AddEventListenerOptions | boolean
   ): void {
-    const this_ = this || window;
+    const this_ = this || globalThis;
 
     requiredArguments("EventTarget.addEventListener", arguments.length, 2);
     const normalizedOptions: domTypes.AddEventListenerOptions = eventTargetHelpers.normalizeAddEventHandlerOptions(
@@ -86,7 +85,7 @@ export class EventTarget implements domTypes.EventTarget {
     callback: (event: domTypes.Event) => void | null,
     options?: domTypes.EventListenerOptions | boolean
   ): void {
-    const this_ = this || window;
+    const this_ = this || globalThis;
 
     requiredArguments("EventTarget.removeEventListener", arguments.length, 2);
     const listeners = this_[domTypes.eventTargetListeners];
@@ -126,7 +125,7 @@ export class EventTarget implements domTypes.EventTarget {
   }
 
   public dispatchEvent(event: domTypes.Event): boolean {
-    const this_ = this || window;
+    const this_ = this || globalThis;
 
     requiredArguments("EventTarget.dispatchEvent", arguments.length, 1);
     const listeners = this_[domTypes.eventTargetListeners];
diff --git a/cli/js/globals.ts b/cli/js/globals.ts
index f090afcd4e..5754002c08 100644
--- a/cli/js/globals.ts
+++ b/cli/js/globals.ts
@@ -1,13 +1,10 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 // This is a "special" module, in that it define the global runtime scope of
 // Deno, and therefore it defines a lot of the runtime environment that code
-// is evaluated in.  We use this file to automatically build the runtime type
-// library.
+// is evaluated in.
 
-// Modules which will make up part of the global public API surface should be
-// imported as namespaces, so when the runtime type library is generated they
-// can be expressed as a namespace in the type library.
-import { window } from "./window.ts";
+// By convention we import those items that are globally exposed as namespaces
 import * as blob from "./blob.ts";
 import * as consoleTypes from "./console.ts";
 import * as csprng from "./get_random_values.ts";
@@ -31,12 +28,10 @@ import * as request from "./request.ts";
 // These imports are not exposed and therefore are fine to just import the
 // symbols required.
 import { core } from "./core.ts";
-
 import { internalObject } from "./internals.ts";
 
-// During the build process, augmentations to the variable `window` in this
-// file are tracked and created as part of default library that is built into
-// Deno, we only need to declare the enough to compile Deno.
+// This global augmentation is just enough types to be able to build Deno,
+// the runtime types are fully defined in `lib.deno_runtime.d.ts`.
 declare global {
   interface CallSite {
     getThis(): unknown;
@@ -65,145 +60,177 @@ declare global {
     [consoleTypes.customInspect]?(): string;
   }
 
-  const console: consoleTypes.Console;
-}
+  interface EvalErrorInfo {
+    isNativeError: boolean;
+    isCompileError: boolean;
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    thrown: any;
+  }
 
-// A self reference to the global object.
-window.window = window;
+  interface DenoCore {
+    print(s: string, isErr?: boolean): void;
+    dispatch(
+      opId: number,
+      control: Uint8Array,
+      zeroCopy?: ArrayBufferView | null
+    ): Uint8Array | null;
+    setAsyncHandler(opId: number, cb: (msg: Uint8Array) => void): void;
+    sharedQueue: {
+      head(): number;
+      numRecords(): number;
+      size(): number;
+      push(buf: Uint8Array): boolean;
+      reset(): void;
+      shift(): Uint8Array | null;
+    };
+
+    ops(): Record<string, number>;
+
+    recv(cb: (opId: number, msg: Uint8Array) => void): void;
+
+    send(
+      opId: number,
+      control: null | ArrayBufferView,
+      data?: ArrayBufferView
+    ): null | Uint8Array;
+
+    shared: SharedArrayBuffer;
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    evalContext(code: string): [any, EvalErrorInfo | null];
+
+    errorToJSON: (e: Error) => string;
+  }
+
+  // Only `var` variables show up in the `globalThis` type when doing a global
+  // scope augmentation.
+  /* eslint-disable no-var */
+  var addEventListener: (
+    type: string,
+    callback: (event: domTypes.Event) => void | null,
+    options?: boolean | domTypes.AddEventListenerOptions | undefined
+  ) => void;
+  var compilerMain: (() => void) | undefined;
+  var console: consoleTypes.Console;
+  var Deno: {
+    core: DenoCore;
+  };
+  var denoMain: (() => void) | undefined;
+  var location: domTypes.Location;
+  var onerror:
+    | ((
+        msg: string,
+        source: string,
+        lineno: number,
+        colno: number,
+        e: domTypes.Event
+      ) => boolean | void)
+    | undefined;
+  var onload: ((e: domTypes.Event) => void) | undefined;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  var onmessage: ((e: { data: any }) => Promise<void> | void) | undefined;
+  var onunload: ((e: domTypes.Event) => void) | undefined;
+  var queueMicrotask: (callback: () => void) => void;
+  var wasmCompilerMain: (() => void) | undefined;
+  var workerMain: (() => Promise<void> | void) | undefined;
+  /* eslint-enable */
+}
 
 // Add internal object to Deno object.
 // This is not exposed as part of the Deno types.
 // @ts-ignore
 Deno[Deno.symbols.internal] = internalObject;
-// This is the Deno namespace, it is handled differently from other window
-// properties when building the runtime type library, as the whole module
-// is flattened into a single namespace.
-window.Deno = Deno;
 
-// Globally available functions and object instances.
-window.atob = textEncoding.atob;
-window.btoa = textEncoding.btoa;
-window.fetch = fetchTypes.fetch;
-window.clearTimeout = timers.clearTimeout;
-window.clearInterval = timers.clearInterval;
-window.console = new consoleTypes.Console(core.print);
-window.setTimeout = timers.setTimeout;
-window.setInterval = timers.setInterval;
-window.location = (undefined as unknown) as domTypes.Location;
-window.onload = undefined as undefined | Function;
-window.onunload = undefined as undefined | Function;
-// The following Crypto interface implementation is not up to par with the
-// standard https://www.w3.org/TR/WebCryptoAPI/#crypto-interface as it does not
-// yet incorporate the SubtleCrypto interface as its "subtle" property.
-window.crypto = (csprng as unknown) as Crypto;
-// window.queueMicrotask added by hand to self-maintained lib.deno_runtime.d.ts
+function writable(value: unknown): PropertyDescriptor {
+  return {
+    value,
+    writable: true,
+    enumerable: true,
+    configurable: true
+  };
+}
 
-// When creating the runtime type library, we use modifications to `window` to
-// determine what is in the global namespace.  When we put a class in the
-// namespace, we also need its global instance type as well, otherwise users
-// won't be able to refer to instances.
-// We have to export the type aliases, so that TypeScript _knows_ they are
-// being used, which it cannot statically determine within this module.
-window.Blob = blob.DenoBlob;
-export type Blob = domTypes.Blob;
+function nonEnumerable(value: unknown): PropertyDescriptor {
+  return {
+    value,
+    writable: true,
+    configurable: true
+  };
+}
 
-export type Body = domTypes.Body;
+function readOnly(value: unknown): PropertyDescriptor {
+  return {
+    value,
+    enumerable: true
+  };
+}
 
-window.File = domFile.DomFileImpl as domTypes.DomFileConstructor;
-export type File = domTypes.DomFile;
+const globalProperties = {
+  window: readOnly(globalThis),
+  Deno: readOnly(Deno),
+  atob: writable(textEncoding.atob),
+  btoa: writable(textEncoding.btoa),
+  fetch: writable(fetchTypes.fetch),
+  clearTimeout: writable(timers.clearTimeout),
+  clearInterval: writable(timers.clearInterval),
+  console: writable(new consoleTypes.Console(core.print)),
+  setTimeout: writable(timers.setTimeout),
+  setInterval: writable(timers.setInterval),
+  onload: writable(undefined),
+  onunload: writable(undefined),
+  crypto: readOnly(csprng),
+  Blob: nonEnumerable(blob.DenoBlob),
+  File: nonEnumerable(domFile.DomFileImpl),
+  CustomEvent: nonEnumerable(customEvent.CustomEvent),
+  Event: nonEnumerable(event.Event),
+  EventTarget: nonEnumerable(eventTarget.EventTarget),
+  URL: nonEnumerable(url.URL),
+  URLSearchParams: nonEnumerable(urlSearchParams.URLSearchParams),
+  Headers: nonEnumerable(headers.Headers),
+  FormData: nonEnumerable(formData.FormData),
+  TextEncoder: nonEnumerable(textEncoding.TextEncoder),
+  TextDecoder: nonEnumerable(textEncoding.TextDecoder),
+  Request: nonEnumerable(request.Request),
+  Response: nonEnumerable(fetchTypes.Response),
+  performance: writable(new performanceUtil.Performance()),
 
-export type CustomEventInit = domTypes.CustomEventInit;
-window.CustomEvent = customEvent.CustomEvent;
-export type CustomEvent = domTypes.CustomEvent;
-export type EventInit = domTypes.EventInit;
-window.Event = event.Event;
-export type Event = domTypes.Event;
-export type EventListener = domTypes.EventListener;
-window.EventTarget = eventTarget.EventTarget;
-export type EventTarget = domTypes.EventTarget;
-window.URL = url.URL;
-export type URL = url.URL;
-window.URLSearchParams = urlSearchParams.URLSearchParams;
-export type URLSearchParams = domTypes.URLSearchParams;
+  onmessage: writable(workers.onmessage),
+  onerror: writable(workers.onerror),
 
-// Using the `as` keyword to use standard compliant interfaces as the Deno
-// implementations contain some implementation details we wouldn't want to
-// expose in the runtime type library.
-window.Headers = headers.Headers as domTypes.HeadersConstructor;
-export type Headers = domTypes.Headers;
-window.FormData = formData.FormData as domTypes.FormDataConstructor;
-export type FormData = domTypes.FormData;
+  workerMain: nonEnumerable(workers.workerMain),
+  workerClose: nonEnumerable(workers.workerClose),
+  postMessage: writable(workers.postMessage),
+  Worker: nonEnumerable(workers.WorkerImpl),
 
-window.TextEncoder = textEncoding.TextEncoder;
-export type TextEncoder = textEncoding.TextEncoder;
-window.TextDecoder = textEncoding.TextDecoder;
-export type TextDecoder = textEncoding.TextDecoder;
+  [domTypes.eventTargetHost]: nonEnumerable(null),
+  [domTypes.eventTargetListeners]: nonEnumerable({}),
+  [domTypes.eventTargetMode]: nonEnumerable(""),
+  [domTypes.eventTargetNodeType]: nonEnumerable(0),
+  [eventTarget.eventTargetAssignedSlot]: nonEnumerable(false),
+  [eventTarget.eventTargetHasActivationBehavior]: nonEnumerable(false),
 
-window.Request = request.Request as domTypes.RequestConstructor;
-export type Request = domTypes.Request;
+  addEventListener: readOnly(
+    eventTarget.EventTarget.prototype.addEventListener
+  ),
+  dispatchEvent: readOnly(eventTarget.EventTarget.prototype.dispatchEvent),
+  removeEventListener: readOnly(
+    eventTarget.EventTarget.prototype.removeEventListener
+  )
+};
 
-window.Response = fetchTypes.Response;
-export type Response = domTypes.Response;
-
-window.performance = new performanceUtil.Performance();
-
-// This variable functioning correctly depends on `declareAsLet`
-// in //tools/ts_library_builder/main.ts
-window.onmessage = workers.onmessage;
-window.onerror = workers.onerror;
-
-window.workerMain = workers.workerMain;
-window.workerClose = workers.workerClose;
-window.postMessage = workers.postMessage;
-
-window.Worker = workers.WorkerImpl;
-export type Worker = workers.Worker;
-
-window[domTypes.eventTargetHost] = null;
-window[domTypes.eventTargetListeners] = {};
-window[domTypes.eventTargetMode] = "";
-window[domTypes.eventTargetNodeType] = 0;
-window[eventTarget.eventTargetAssignedSlot] = false;
-window[eventTarget.eventTargetHasActivationBehavior] = false;
-window.addEventListener = eventTarget.EventTarget.prototype.addEventListener;
-window.dispatchEvent = eventTarget.EventTarget.prototype.dispatchEvent;
-window.removeEventListener =
-  eventTarget.EventTarget.prototype.removeEventListener;
+Object.defineProperties(globalThis, globalProperties);
 
 // Registers the handler for window.onload function.
-window.addEventListener("load", (e: domTypes.Event): void => {
-  const onload = window.onload;
+globalThis.addEventListener("load", (e: domTypes.Event): void => {
+  const { onload } = globalThis;
   if (typeof onload === "function") {
     onload(e);
   }
 });
 // Registers the handler for window.onunload function.
-window.addEventListener("unload", (e: domTypes.Event): void => {
-  const onunload = window.onunload;
+globalThis.addEventListener("unload", (e: domTypes.Event): void => {
+  const { onunload } = globalThis;
   if (typeof onunload === "function") {
     onunload(e);
   }
 });
-
-// below are interfaces that are available in TypeScript but
-// have different signatures
-export interface ImportMeta {
-  url: string;
-  main: boolean;
-}
-
-export interface Crypto {
-  readonly subtle: null;
-  getRandomValues: <
-    T extends
-      | Int8Array
-      | Uint8Array
-      | Uint8ClampedArray
-      | Int16Array
-      | Uint16Array
-      | Int32Array
-      | Uint32Array
-  >(
-    typedArray: T
-  ) => T;
-}
diff --git a/cli/js/lib.deno_runtime.d.ts b/cli/js/lib.deno_runtime.d.ts
index 6e3e2384a0..95c22305bf 100644
--- a/cli/js/lib.deno_runtime.d.ts
+++ b/cli/js/lib.deno_runtime.d.ts
@@ -2200,8 +2200,16 @@ declare const TextDecoder: typeof __textEncoding.TextDecoder;
 declare const Request: __domTypes.RequestConstructor;
 declare const Response: typeof __fetch.Response;
 declare const performance: __performanceUtil.Performance;
-declare let onmessage: (e: { data: any }) => void;
-declare let onerror: (e: Event) => void;
+declare let onmessage: ((e: { data: any }) => Promise<void> | void) | undefined;
+declare let onerror:
+  | ((
+      msg: string,
+      source: string,
+      lineno: number,
+      colno: number,
+      e: Event
+    ) => boolean | void)
+  | undefined;
 declare const workerMain: typeof __workers.workerMain;
 declare const workerClose: typeof __workers.workerClose;
 declare const postMessage: typeof __workers.postMessage;
diff --git a/cli/js/location.ts b/cli/js/location.ts
index fdcae6abde..3033740554 100644
--- a/cli/js/location.ts
+++ b/cli/js/location.ts
@@ -2,7 +2,6 @@
 import { URL } from "./url.ts";
 import { notImplemented } from "./util.ts";
 import { Location } from "./dom_types.ts";
-import { window } from "./window.ts";
 
 export class LocationImpl implements Location {
   constructor(url: string) {
@@ -47,6 +46,6 @@ export class LocationImpl implements Location {
 }
 
 export function setLocation(url: string): void {
-  window.location = new LocationImpl(url);
-  Object.freeze(window.location);
+  globalThis.location = new LocationImpl(url);
+  Object.freeze(globalThis.location);
 }
diff --git a/cli/js/main.ts b/cli/js/main.ts
index 0056862308..11dac5038a 100644
--- a/cli/js/main.ts
+++ b/cli/js/main.ts
@@ -7,7 +7,6 @@ import { args } from "./deno.ts";
 import { setPrepareStackTrace } from "./error_stack.ts";
 import { replLoop } from "./repl.ts";
 import { setVersions } from "./version.ts";
-import { window } from "./window.ts";
 import { setLocation } from "./location.ts";
 import { setBuildInfo } from "./build.ts";
 import { setSignals } from "./process.ts";
@@ -36,4 +35,4 @@ function denoMain(preserveDenoNamespace = true, name?: string): void {
     replLoop();
   }
 }
-window["denoMain"] = denoMain;
+globalThis["denoMain"] = denoMain;
diff --git a/cli/js/mixins/dom_iterable.ts b/cli/js/mixins/dom_iterable.ts
index dcbd5150ec..aec4e7aa01 100644
--- a/cli/js/mixins/dom_iterable.ts
+++ b/cli/js/mixins/dom_iterable.ts
@@ -1,7 +1,6 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 import { DomIterable } from "../dom_types.ts";
-import { window } from "../window.ts";
 import { requiredArguments } from "../util.ts";
 import { exposeForTest } from "../internals.ts";
 
@@ -57,7 +56,9 @@ export function DomIterableMixin<K, V, TBase extends Constructor>(
         arguments.length,
         1
       );
-      callbackfn = callbackfn.bind(thisArg == null ? window : Object(thisArg));
+      callbackfn = callbackfn.bind(
+        thisArg == null ? globalThis : Object(thisArg)
+      );
       // eslint-disable-next-line @typescript-eslint/no-explicit-any
       for (const [key, value] of (this as any)[dataSymbol]) {
         callbackfn(value, key, this);
diff --git a/cli/js/os.ts b/cli/js/os.ts
index 9b4301aea5..2a3a51de7b 100644
--- a/cli/js/os.ts
+++ b/cli/js/os.ts
@@ -5,7 +5,6 @@ import { sendSync } from "./dispatch_json.ts";
 import { ErrorKind } from "./errors.ts";
 import { assert } from "./util.ts";
 import * as util from "./util.ts";
-import { window } from "./window.ts";
 import { OperatingSystem, Arch } from "./build.ts";
 
 /** Check if running in terminal.
@@ -109,21 +108,21 @@ export function start(preserveDenoNamespace = true, source?: string): Start {
 
   // pid and noColor need to be set in the Deno module before it's set to be
   // frozen.
-  util.immutableDefine(window.Deno, "pid", pid);
-  util.immutableDefine(window.Deno, "noColor", noColor);
-  Object.freeze(window.Deno);
+  util.immutableDefine(globalThis.Deno, "pid", pid);
+  util.immutableDefine(globalThis.Deno, "noColor", noColor);
+  Object.freeze(globalThis.Deno);
 
   if (preserveDenoNamespace) {
-    util.immutableDefine(window, "Deno", window.Deno);
+    util.immutableDefine(globalThis, "Deno", globalThis.Deno);
     // Deno.core could ONLY be safely frozen here (not in globals.ts)
     // since shared_queue.js will modify core properties.
-    Object.freeze(window.Deno.core);
+    Object.freeze(globalThis.Deno.core);
     // core.sharedQueue is an object so we should also freeze it.
-    Object.freeze(window.Deno.core.sharedQueue);
+    Object.freeze(globalThis.Deno.core.sharedQueue);
   } else {
-    // Remove window.Deno
-    delete window.Deno;
-    assert(window.Deno === undefined);
+    // Remove globalThis.Deno
+    delete globalThis.Deno;
+    assert(globalThis.Deno === undefined);
   }
 
   return startResponse;
diff --git a/cli/js/repl.ts b/cli/js/repl.ts
index 922cd499d6..813f0cb219 100644
--- a/cli/js/repl.ts
+++ b/cli/js/repl.ts
@@ -1,7 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { close } from "./files.ts";
 import { exit } from "./os.ts";
-import { window } from "./window.ts";
 import { core } from "./core.ts";
 import { formatError } from "./format_error.ts";
 import { stringifyArgs } from "./console.ts";
@@ -104,8 +103,8 @@ function evaluate(code: string): boolean {
 
 // @internal
 export async function replLoop(): Promise<void> {
-  const { console } = window;
-  Object.defineProperties(window, replCommands);
+  const { console } = globalThis;
+  Object.defineProperties(globalThis, replCommands);
 
   const historyFile = "deno_history.txt";
   const rid = startRepl(historyFile);
@@ -118,12 +117,12 @@ export async function replLoop(): Promise<void> {
     exit(exitCode);
   };
 
-  // Configure window._ to give the last evaluation result.
-  Object.defineProperty(window, "_", {
+  // Configure globalThis._ to give the last evaluation result.
+  Object.defineProperty(globalThis, "_", {
     configurable: true,
     get: (): Value => lastEvalResult,
     set: (value: Value): Value => {
-      Object.defineProperty(window, "_", {
+      Object.defineProperty(globalThis, "_", {
         value: value,
         writable: true,
         enumerable: true,
@@ -133,12 +132,12 @@ export async function replLoop(): Promise<void> {
     }
   });
 
-  // Configure window._error to give the last thrown error.
-  Object.defineProperty(window, "_error", {
+  // Configure globalThis._error to give the last thrown error.
+  Object.defineProperty(globalThis, "_error", {
     configurable: true,
     get: (): Value => lastThrownError,
     set: (value: Value): Value => {
-      Object.defineProperty(window, "_error", {
+      Object.defineProperty(globalThis, "_error", {
         value: value,
         writable: true,
         enumerable: true,
diff --git a/cli/js/timers.ts b/cli/js/timers.ts
index e3b3fdd2ac..da8fc7a228 100644
--- a/cli/js/timers.ts
+++ b/cli/js/timers.ts
@@ -1,11 +1,10 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { assert } from "./util.ts";
-import { window } from "./window.ts";
 import * as dispatch from "./dispatch.ts";
 import { sendSync, sendAsync } from "./dispatch_json.ts";
 import { RBTree } from "./rbtree.ts";
 
-const { console } = window;
+const { console } = globalThis;
 
 interface Timer {
   id: number;
@@ -173,7 +172,7 @@ function fireTimers(): void {
   if (pendingFireTimers.length > 0) {
     hasPendingFireTimers = true;
     // Fire the list of pending timers as a chain of microtasks.
-    window.queueMicrotask(firePendingTimers);
+    globalThis.queueMicrotask(firePendingTimers);
   } else {
     setOrClearGlobalTimeout(nextDueNode && nextDueNode.due, now);
   }
@@ -198,14 +197,14 @@ function firePendingTimers(): void {
     // Fire a single timer and allow its children microtasks scheduled first.
     fire(pendingFireTimers.shift()!);
     // ...and we schedule next timer after this.
-    window.queueMicrotask(firePendingTimers);
+    globalThis.queueMicrotask(firePendingTimers);
   }
 }
 
 export type Args = unknown[];
 
 function checkThis(thisArg: unknown): void {
-  if (thisArg !== null && thisArg !== undefined && thisArg !== window) {
+  if (thisArg !== null && thisArg !== undefined && thisArg !== globalThis) {
     throw new TypeError("Illegal invocation");
   }
 }
@@ -222,8 +221,8 @@ function setTimer(
   args: Args,
   repeat: boolean
 ): number {
-  // Bind `args` to the callback and bind `this` to window(global).
-  const callback: () => void = cb.bind(window, ...args);
+  // Bind `args` to the callback and bind `this` to globalThis(global).
+  const callback: () => void = cb.bind(globalThis, ...args);
   // In the browser, the delay value must be coercible to an integer between 0
   // and INT32_MAX. Any other value will cause the timer to fire immediately.
   // We emulate this behavior.
diff --git a/cli/js/url.ts b/cli/js/url.ts
index 1619ec26f0..477ca7c2a8 100644
--- a/cli/js/url.ts
+++ b/cli/js/url.ts
@@ -2,7 +2,6 @@
 import * as urlSearchParams from "./url_search_params.ts";
 import * as domTypes from "./dom_types.ts";
 import { getRandomValues } from "./get_random_values.ts";
-import { window } from "./window.ts";
 import { customInspect } from "./console.ts";
 
 interface URLParts {
@@ -374,7 +373,7 @@ export class URL {
 
   // TODO(kevinkassimo): implement MediaSource version in the future.
   static createObjectURL(b: domTypes.Blob): string {
-    const origin = window.location.origin || "http://deno-opaque-origin";
+    const origin = globalThis.location.origin || "http://deno-opaque-origin";
     const key = `blob:${origin}/${generateUUID()}`;
     blobURLMap.set(key, b);
     return key;
@@ -391,7 +390,7 @@ export class URL {
       return;
     }
     // Origin match check seems irrelevant for now, unless we implement
-    // persisten storage for per window.location.origin at some point.
+    // persisten storage for per globalThis.location.origin at some point.
     blobURLMap.delete(url);
   }
 }
diff --git a/cli/js/util.ts b/cli/js/util.ts
index 928794beae..e779fb5d73 100644
--- a/cli/js/util.ts
+++ b/cli/js/util.ts
@@ -1,6 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { atob } from "./text_encoding.ts";
 import { TypedArray } from "./types.ts";
-import { window } from "./window.ts";
 
 let logDebug = false;
 let logSource = "JS";
@@ -19,9 +19,9 @@ export function setLogDebug(debug: boolean, source?: string): void {
  */
 export function log(...args: unknown[]): void {
   if (logDebug) {
-    // if we destructure `console` off `window` too early, we don't bind to
+    // if we destructure `console` off `globalThis` too early, we don't bind to
     // the right console, therefore we don't log anything out.
-    window.console.log(`DEBUG ${logSource} -`, ...args);
+    globalThis.console.log(`DEBUG ${logSource} -`, ...args);
   }
 }
 
@@ -345,7 +345,7 @@ export function humanFileSize(bytes: number): string {
 
 // @internal
 export function base64ToUint8Array(data: string): Uint8Array {
-  const binString = window.atob(data);
+  const binString = atob(data);
   const size = binString.length;
   const bytes = new Uint8Array(size);
   for (let i = 0; i < size; i++) {
diff --git a/cli/js/window.ts b/cli/js/window.ts
deleted file mode 100644
index 3eed4ca583..0000000000
--- a/cli/js/window.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-// (0, eval) is indirect eval.
-// See the links below for details:
-// - https://stackoverflow.com/a/14120023
-// - https://tc39.github.io/ecma262/#sec-performeval (spec)
-export const window = (0, eval)("this");
-// TODO: The above should be replaced with globalThis
-// when the globalThis proposal goes to stage 4
-// See https://github.com/tc39/proposal-global
diff --git a/cli/js/workers.ts b/cli/js/workers.ts
index d1d8f78e2c..7e8219e19f 100644
--- a/cli/js/workers.ts
+++ b/cli/js/workers.ts
@@ -4,9 +4,9 @@ import * as dispatch from "./dispatch.ts";
 import { sendAsync, sendSync } from "./dispatch_json.ts";
 import { log, createResolvable, Resolvable } from "./util.ts";
 import { TextDecoder, TextEncoder } from "./text_encoding.ts";
-import { window } from "./window.ts";
 import { blobURLMap } from "./url.ts";
 import { blobBytesWeakMap } from "./blob.ts";
+import { Event } from "./event.ts";
 import { EventTarget } from "./event_target.ts";
 
 const encoder = new TextEncoder();
@@ -106,16 +106,19 @@ export async function workerMain(): Promise<void> {
     const event = { data };
 
     try {
-      result = window.onmessage(event);
+      if (!globalThis["onmessage"]) {
+        break;
+      }
+      result = globalThis.onmessage!(event);
       if (result && "then" in result) {
         await result;
       }
-      if (!window["onmessage"]) {
+      if (!globalThis["onmessage"]) {
         break;
       }
     } catch (e) {
-      if (window["onerror"]) {
-        const result = window.onerror(
+      if (globalThis["onerror"]) {
+        const result = globalThis.onerror(
           e.message,
           e.fileName,
           e.lineNumber,
@@ -145,7 +148,7 @@ export interface Worker {
 export interface WorkerOptions {}
 
 /** Extended Deno Worker initialization options.
- * `noDenoNamespace` hides global `window.Deno` namespace for
+ * `noDenoNamespace` hides global `globalThis.Deno` namespace for
  * spawned worker and nested workers spawned by it (default: false).
  */
 export interface DenoWorkerOptions extends WorkerOptions {
@@ -202,7 +205,9 @@ export class WorkerImpl extends EventTarget implements Worker {
   }
 
   private handleError(e: any): boolean {
-    const event = new window.Event("error", { cancelable: true });
+    // TODO: this is being handled in a type unsafe way, it should be type safe
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const event = new Event("error", { cancelable: true }) as any;
     event.message = e.message;
     event.lineNumber = e.lineNumber ? e.lineNumber + 1 : null;
     event.columnNumber = e.columnNumber ? e.columnNumber + 1 : null;
diff --git a/cli/source_maps.rs b/cli/source_maps.rs
index d3cda390d4..e326c644e7 100644
--- a/cli/source_maps.rs
+++ b/cli/source_maps.rs
@@ -412,7 +412,7 @@ mod tests {
     assert_eq!(actual.message, "TypeError: baz");
     // Because this is accessing the live bundle, this test might be more fragile
     assert_eq!(actual.frames.len(), 1);
-    assert!(actual.frames[0].script_name.ends_with("/window.ts"));
+    assert!(actual.frames[0].script_name.ends_with("/dom_types.ts"));
   }
 
   #[test]
diff --git a/deno_typescript/compiler_main.js b/deno_typescript/compiler_main.js
index 5cf44b689b..94b38e070c 100644
--- a/deno_typescript/compiler_main.js
+++ b/deno_typescript/compiler_main.js
@@ -144,7 +144,7 @@ class Host {
    * @param {ts.CompilerOptions} _options
    */
   getDefaultLibFileName(_options) {
-    return "lib.deno_core.d.ts";
+    return "lib.esnext.d.ts";
   }
 
   getDefaultLibLocation() {
diff --git a/deno_typescript/lib.deno_core.d.ts b/deno_typescript/lib.deno_core.d.ts
deleted file mode 100644
index 21ce6a67f0..0000000000
--- a/deno_typescript/lib.deno_core.d.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-
-// This file contains APIs that are introduced into the global namespace by
-// Deno core.  These are not intended to be used directly by runtime users of
-// Deno and therefore do not flow through to the runtime type library.
-
-declare interface MessageCallback {
-  (msg: Uint8Array): void;
-}
-
-interface EvalErrorInfo {
-  // Is the object thrown a native Error?
-  isNativeError: boolean;
-  // Was the error happened during compilation?
-  isCompileError: boolean;
-  // The actual thrown entity
-  // (might be an Error or anything else thrown by the user)
-  // If isNativeError is true, this is an Error
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  thrown: any;
-}
-
-declare interface DenoCore {
-  print(s: string, isErr?: boolean): void;
-  dispatch(
-    opId: number,
-    control: Uint8Array,
-    zeroCopy?: ArrayBufferView | null
-  ): Uint8Array | null;
-  setAsyncHandler(opId: number, cb: MessageCallback): void;
-  sharedQueue: {
-    head(): number;
-    numRecords(): number;
-    size(): number;
-    push(buf: Uint8Array): boolean;
-    reset(): void;
-    shift(): Uint8Array | null;
-  };
-
-  ops(): Record<string, number>;
-
-  recv(cb: (opId: number, msg: Uint8Array) => void): void;
-
-  send(
-    opId: number,
-    control: null | ArrayBufferView,
-    data?: ArrayBufferView
-  ): null | Uint8Array;
-
-  shared: SharedArrayBuffer;
-
-  /** Evaluate provided code in the current context.
-   * It differs from eval(...) in that it does not create a new context.
-   * Returns an array: [output, errInfo].
-   * If an error occurs, `output` becomes null and `errInfo` is non-null.
-   */
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  evalContext(code: string): [any, EvalErrorInfo | null];
-
-  errorToJSON: (e: Error) => string;
-}
-
-declare interface DenoInterface {
-  core: DenoCore;
-}
-declare let Deno: DenoInterface;
diff --git a/deno_typescript/lib.rs b/deno_typescript/lib.rs
index 779e6fd70c..370079fa14 100644
--- a/deno_typescript/lib.rs
+++ b/deno_typescript/lib.rs
@@ -146,7 +146,7 @@ pub fn compile_bundle(
     },
   });
 
-  let mut root_names_str: Vec<String> = root_names
+  let root_names_str: Vec<String> = root_names
     .iter()
     .map(|p| {
       if !p.exists() {
@@ -158,7 +158,6 @@ pub fn compile_bundle(
       module_specifier.as_str().to_string()
     })
     .collect();
-  root_names_str.push("$asset$/lib.deno_core.d.ts".to_string());
 
   // TODO lift js_check to caller?
   let state = js_check(ts_isolate.compile(&config_json, root_names_str));
@@ -267,9 +266,6 @@ pub fn get_asset(name: &str) -> Option<String> {
     "bundle_loader.js" => {
       Some(read_file("../deno_typescript/bundle_loader.js"))
     }
-    "lib.deno_core.d.ts" => {
-      Some(read_file("../deno_typescript/lib.deno_core.d.ts"))
-    }
     "lib.deno_runtime.d.ts" => Some(read_file("js/lib.deno_runtime.d.ts")),
     "bootstrap.ts" => Some("console.log(\"hello deno\");".to_string()),
     "typescript.d.ts" => inc!("typescript.d.ts"),