refactor: Event and EventTarget implementations (#4707)

Refactors Event and EventTarget so that they better encapsulate their
non-public data as well as are more forward compatible with things like
DOM Nodes.

Moves `dom_types.ts` -> `dom_types.d.ts` which was always the intention,
it was a legacy of when we used to build the types from the code and the
limitations of the compiler.  There was a lot of cruft in `dom_types`
which shouldn't have been there, and mis-alignment to the DOM standards.
This generally has been eliminated, though we still have some minor
differences from the DOM (like the removal of some deprecated
methods/properties).

Adds `DOMException`.  Strictly it shouldn't inherit from `Error`, but
most browsers provide a stack trace when one is thrown, so the behaviour
in Deno actually better matches the browser.

`Event` still doesn't log to console like it does in the browser.  I
 wanted to get this raised and that could be an enhancement later on (it
 currently doesn't either).

1 files changed, 13 insertions, 3 deletions

diff --git a/cli/js/web/dom_iterable.ts b/cli/js/web/dom_iterable.ts
index 191958f11..fcbca307f 100644
--- a/cli/js/web/dom_iterable.ts
+++ b/cli/js/web/dom_iterable.ts
@@ -1,11 +1,21 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-// eslint-disable-next-line @typescript-eslint/no-unused-vars
-import { DomIterable } from "./dom_types.ts";
 import { requiredArguments } from "./util.ts";
 import { exposeForTest } from "../internals.ts";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-type Constructor<T = {}> = new (...args: any[]) => T;
+export type Constructor<T = {}> = new (...args: any[]) => T;
+
+export interface DomIterable<K, V> {
+  keys(): IterableIterator<K>;
+  values(): IterableIterator<V>;
+  entries(): IterableIterator<[K, V]>;
+  [Symbol.iterator](): IterableIterator<[K, V]>;
+  forEach(
+    callback: (value: V, key: K, parent: this) => void,
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    thisArg?: any
+  ): void;
+}
 
 export function DomIterableMixin<K, V, TBase extends Constructor>(
   Base: TBase,