11 files changed, 89 insertions, 16 deletions
diff --git a/cli/js/web/console.ts b/cli/js/web/console.ts
index 601d5fd09..8a34d62a1 100644
--- a/cli/js/web/console.ts
+++ b/cli/js/web/console.ts
@@ -1,6 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { isTypedArray } from "../util.ts";
-import { TypedArray } from "../types.ts";
+import { isTypedArray, TypedArray } from "./util.ts";
 import { TextEncoder } from "./text_encoding.ts";
 import { File, stdout } from "../files.ts";
 import { cliTable } from "./console_table.ts";
diff --git a/cli/js/web/console_table.ts b/cli/js/web/console_table.ts
index 276d77f1d..7e698f712 100644
--- a/cli/js/web/console_table.ts
+++ b/cli/js/web/console_table.ts
@@ -2,7 +2,7 @@
 // Forked from Node's lib/internal/cli_table.js
 
 import { TextEncoder } from "./text_encoding.ts";
-import { hasOwnProperty } from "../util.ts";
+import { hasOwnProperty } from "./util.ts";
 
 const encoder = new TextEncoder();
 
diff --git a/cli/js/web/custom_event.ts b/cli/js/web/custom_event.ts
index 6c8a3c19b..2d94df56d 100644
--- a/cli/js/web/custom_event.ts
+++ b/cli/js/web/custom_event.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import * as domTypes from "./dom_types.ts";
 import * as event from "./event.ts";
-import { getPrivateValue, requiredArguments } from "../util.ts";
+import { getPrivateValue, requiredArguments } from "./util.ts";
 
 // WeakMaps are recommended for private attributes (see MDN link below)
 // https://developer.mozilla.org/en-US/docs/Archive/Add-ons/Add-on_SDK/Guides/Contributor_s_Guide/Private_Properties#Using_WeakMaps
diff --git a/cli/js/web/dom_iterable.ts b/cli/js/web/dom_iterable.ts
index bd8e7d8cd..f365d555f 100644
--- a/cli/js/web/dom_iterable.ts
+++ b/cli/js/web/dom_iterable.ts
@@ -1,7 +1,7 @@
 // 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 { requiredArguments } from "./util.ts";
 import { exposeForTest } from "../internals.ts";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
diff --git a/cli/js/web/event.ts b/cli/js/web/event.ts
index e365fb6b2..a30e33447 100644
--- a/cli/js/web/event.ts
+++ b/cli/js/web/event.ts
@@ -1,6 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import * as domTypes from "./dom_types.ts";
-import { getPrivateValue, requiredArguments } from "../util.ts";
+import { getPrivateValue, requiredArguments } from "./util.ts";
 
 // WeakMaps are recommended for private attributes (see MDN link below)
 // https://developer.mozilla.org/en-US/docs/Archive/Add-ons/Add-on_SDK/Guides/Contributor_s_Guide/Private_Properties#Using_WeakMaps
diff --git a/cli/js/web/event_target.ts b/cli/js/web/event_target.ts
index 09e80a731..03557526a 100644
--- a/cli/js/web/event_target.ts
+++ b/cli/js/web/event_target.ts
@@ -1,6 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import * as domTypes from "./dom_types.ts";
-import { hasOwnProperty, requiredArguments } from "../util.ts";
+import { hasOwnProperty, requiredArguments } from "./util.ts";
 import {
   getRoot,
   isNode,
diff --git a/cli/js/web/fetch.ts b/cli/js/web/fetch.ts
index d9918ba14..daa926e51 100644
--- a/cli/js/web/fetch.ts
+++ b/cli/js/web/fetch.ts
@@ -1,10 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import {
-  assert,
-  createResolvable,
-  notImplemented,
-  isTypedArray
-} from "../util.ts";
+import { assert, createResolvable, notImplemented } from "../util.ts";
+import { isTypedArray } from "./util.ts";
 import * as domTypes from "./dom_types.ts";
 import { TextDecoder, TextEncoder } from "./text_encoding.ts";
 import { DenoBlob, bytesSymbol as blobBytesSymbol } from "./blob.ts";
diff --git a/cli/js/web/form_data.ts b/cli/js/web/form_data.ts
index 9c0590c32..461210b9d 100644
--- a/cli/js/web/form_data.ts
+++ b/cli/js/web/form_data.ts
@@ -3,7 +3,7 @@ import * as domTypes from "./dom_types.ts";
 import * as blob from "./blob.ts";
 import * as domFile from "./dom_file.ts";
 import { DomIterableMixin } from "./dom_iterable.ts";
-import { requiredArguments } from "../util.ts";
+import { requiredArguments } from "./util.ts";
 
 const dataSymbol = Symbol("data");
 
diff --git a/cli/js/web/headers.ts b/cli/js/web/headers.ts
index 652dd2de6..9ff594224 100644
--- a/cli/js/web/headers.ts
+++ b/cli/js/web/headers.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import * as domTypes from "./dom_types.ts";
 import { DomIterableMixin } from "./dom_iterable.ts";
-import { requiredArguments } from "../util.ts";
+import { requiredArguments } from "./util.ts";
 import { customInspect } from "./console.ts";
 
 // From node-fetch
diff --git a/cli/js/web/url_search_params.ts b/cli/js/web/url_search_params.ts
index 2248a5388..ed93045da 100644
--- a/cli/js/web/url_search_params.ts
+++ b/cli/js/web/url_search_params.ts
@@ -1,6 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { URL } from "./url.ts";
-import { requiredArguments } from "../util.ts";
+import { requiredArguments } from "./util.ts";
 
 // Returns whether o is iterable.
 // @internal
diff --git a/cli/js/web/util.ts b/cli/js/web/util.ts
new file mode 100644
index 000000000..b0a050973
--- /dev/null
+++ b/cli/js/web/util.ts
@@ -0,0 +1,78 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+export type TypedArray = Uint8Array | Float32Array | Int32Array;
+const TypedArrayConstructor = Object.getPrototypeOf(Uint8Array);
+export function isTypedArray(x: unknown): x is TypedArray {
+  return x instanceof TypedArrayConstructor;
+}
+
+// @internal
+export function requiredArguments(
+  name: string,
+  length: number,
+  required: number
+): void {
+  if (length < required) {
+    const errMsg = `${name} requires at least ${required} argument${
+      required === 1 ? "" : "s"
+    }, but only ${length} present`;
+    throw new TypeError(errMsg);
+  }
+}
+
+// @internal
+export function immutableDefine(
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  o: any,
+  p: string | number | symbol,
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  value: any
+): void {
+  Object.defineProperty(o, p, {
+    value,
+    configurable: false,
+    writable: false
+  });
+}
+
+// Returns values from a WeakMap to emulate private properties in JavaScript
+export function getPrivateValue<
+  K extends object,
+  V extends object,
+  W extends keyof V
+>(instance: K, weakMap: WeakMap<K, V>, key: W): V[W] {
+  if (weakMap.has(instance)) {
+    return weakMap.get(instance)![key];
+  }
+  throw new TypeError("Illegal invocation");
+}
+
+/**
+ * Determines whether an object has a property with the specified name.
+ * Avoid calling prototype builtin `hasOwnProperty` for two reasons:
+ *
+ * 1. `hasOwnProperty` is defined on the object as something else:
+ *
+ *      const options = {
+ *        ending: 'utf8',
+ *        hasOwnProperty: 'foo'
+ *      };
+ *      options.hasOwnProperty('ending') // throws a TypeError
+ *
+ * 2. The object doesn't inherit from `Object.prototype`:
+ *
+ *       const options = Object.create(null);
+ *       options.ending = 'utf8';
+ *       options.hasOwnProperty('ending'); // throws a TypeError
+ *
+ * @param obj A Object.
+ * @param v A property name.
+ * @see https://eslint.org/docs/rules/no-prototype-builtins
+ * @internal
+ */
+export function hasOwnProperty<T>(obj: T, v: PropertyKey): boolean {
+  if (obj == null) {
+    return false;
+  }
+  return Object.prototype.hasOwnProperty.call(obj, v);
+}