clean up code in cli/js (#6611)

26 files changed, 107 insertions, 113 deletions

diff --git a/cli/js/web/README.md b/cli/js/web/README.md
index f220c0da6..01672fe76 100644
--- a/cli/js/web/README.md
+++ b/cli/js/web/README.md
@@ -2,10 +2,10 @@
 
 This directory facilities Web APIs that are available in Deno.
 
-Please note, that some of implementations might not be completely aligned with
+Please note, that some implementations might not be completely aligned with
 specification.
 
-Some of the Web APIs are using ops under the hood, eg. `console`, `performance`.
+Some Web APIs are using ops under the hood, eg. `console`, `performance`.
 
 ## Implemented Web APIs
 
diff --git a/cli/js/web/abort_controller.ts b/cli/js/web/abort_controller.ts
index 5b0a3af3c..376376092 100644
--- a/cli/js/web/abort_controller.ts
+++ b/cli/js/web/abort_controller.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { AbortSignalImpl, signalAbort } from "./abort_signal.ts";
 
 export class AbortControllerImpl implements AbortController {
diff --git a/cli/js/web/base64.ts b/cli/js/web/base64.ts
index 4d30e00f1..328311d03 100644
--- a/cli/js/web/base64.ts
+++ b/cli/js/web/base64.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 // Forked from https://github.com/beatgammit/base64-js
 // Copyright (c) 2014 Jameson Little. MIT License.
 
diff --git a/cli/js/web/blob.ts b/cli/js/web/blob.ts
index 899c67135..92286029f 100644
--- a/cli/js/web/blob.ts
+++ b/cli/js/web/blob.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { TextDecoder, TextEncoder } from "./text_encoding.ts";
 import { build } from "../build.ts";
 import { ReadableStreamImpl } from "./streams/readable_stream.ts";
diff --git a/cli/js/web/body.ts b/cli/js/web/body.ts
index 35fc5ebbe..80c4b646a 100644
--- a/cli/js/web/body.ts
+++ b/cli/js/web/body.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import * as blob from "./blob.ts";
 import * as encoding from "./text_encoding.ts";
 import * as domTypes from "./dom_types.d.ts";
diff --git a/cli/js/web/console.ts b/cli/js/web/console.ts
index f6ea7a0a7..1f96bfe9d 100644
--- a/cli/js/web/console.ts
+++ b/cli/js/web/console.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { isInvalidDate, isTypedArray, TypedArray } from "./util.ts";
 import { cliTable } from "./console_table.ts";
 import { exposeForTest } from "../internals.ts";
@@ -381,7 +382,7 @@ function createTypedArrayString(
     displayName: `${typedArrayName}(${valueLength})`,
     delims: ["[", "]"],
     entryHandler: (entry, ctx, level, maxLevel): string => {
-      const [_, val] = entry;
+      const val = entry[1];
       return stringifyWithQuotes(val, ctx, level + 1, maxLevel);
     },
     group: true,
@@ -400,7 +401,7 @@ function createSetString(
     displayName: "Set",
     delims: ["{", "}"],
     entryHandler: (entry, ctx, level, maxLevel): string => {
-      const [_, val] = entry;
+      const val = entry[1];
       return stringifyWithQuotes(val, ctx, level + 1, maxLevel);
     },
     group: false,
@@ -508,7 +509,7 @@ function createRawObjectString(
   }
   ctx.add(value);
 
-  let baseString = "";
+  let baseString: string;
 
   let shouldShowDisplayName = false;
   let displayName = (value as { [Symbol.toStringTag]: string })[
@@ -724,7 +725,7 @@ const timerMap = new Map<string, number>();
 const isConsoleInstance = Symbol("isConsoleInstance");
 
 export class Console {
-  #printFunc: PrintFunc;
+  readonly #printFunc: PrintFunc;
   indentLevel: number;
   [isConsoleInstance] = false;
 
diff --git a/cli/js/web/console_table.ts b/cli/js/web/console_table.ts
index 55808cdc0..ba2d763b7 100644
--- a/cli/js/web/console_table.ts
+++ b/cli/js/web/console_table.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 // Copyright Joyent, Inc. and other Node contributors. MIT license.
 // Forked from Node's lib/internal/cli_table.js
 
diff --git a/cli/js/web/custom_event.ts b/cli/js/web/custom_event.ts
index ea76d2c94..dad89f650 100644
--- a/cli/js/web/custom_event.ts
+++ b/cli/js/web/custom_event.ts
@@ -1,10 +1,11 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { EventImpl as Event } from "./event.ts";
 import { requiredArguments } from "./util.ts";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 export class CustomEventImpl<T = any> extends Event implements CustomEvent {
-  #detail: T;
+  readonly #detail: T;
 
   constructor(type: string, eventInitDict: CustomEventInit<T> = {}) {
     super(type, eventInitDict);
diff --git a/cli/js/web/decode_utf8.ts b/cli/js/web/decode_utf8.ts
index c1f879b54..d82634efe 100644
--- a/cli/js/web/decode_utf8.ts
+++ b/cli/js/web/decode_utf8.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 // This module is based on Bjoern Hoehrmann's DFA UTF-8 decoder.
 // See http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for details.
 //
diff --git a/cli/js/web/dom_exception.ts b/cli/js/web/dom_exception.ts
index e2c77d41c..5e7d5ee6f 100644
--- a/cli/js/web/dom_exception.ts
+++ b/cli/js/web/dom_exception.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
 export class DOMExceptionImpl extends Error implements DOMException {
-  #name: string;
+  readonly #name: string;
 
   constructor(message = "", name = "Error") {
     super(message);
diff --git a/cli/js/web/dom_file.ts b/cli/js/web/dom_file.ts
index 792d96dd1..3d65e5768 100644
--- a/cli/js/web/dom_file.ts
+++ b/cli/js/web/dom_file.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import * as blob from "./blob.ts";
 
 export class DomFileImpl extends blob.DenoBlob implements File {
diff --git a/cli/js/web/dom_iterable.ts b/cli/js/web/dom_iterable.ts
index fcbca307f..271b2f655 100644
--- a/cli/js/web/dom_iterable.ts
+++ b/cli/js/web/dom_iterable.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { requiredArguments } from "./util.ts";
 import { exposeForTest } from "../internals.ts";
 
diff --git a/cli/js/web/error_event.ts b/cli/js/web/error_event.ts
index fbdd19fb5..8e7853875 100644
--- a/cli/js/web/error_event.ts
+++ b/cli/js/web/error_event.ts
@@ -4,12 +4,12 @@ import { EventImpl as Event } from "./event.ts";
 import { defineEnumerableProps } from "./util.ts";
 
 export class ErrorEventImpl extends Event implements ErrorEvent {
-  #message: string;
-  #filename: string;
-  #lineno: number;
-  #colno: number;
+  readonly #message: string;
+  readonly #filename: string;
+  readonly #lineno: number;
+  readonly #colno: number;
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  #error: any;
+  readonly #error: any;
 
   get message(): string {
     return this.#message;
diff --git a/cli/js/web/fetch.ts b/cli/js/web/fetch.ts
index 0c419178a..156c218a4 100644
--- a/cli/js/web/fetch.ts
+++ b/cli/js/web/fetch.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { notImplemented } from "../util.ts";
 import { isTypedArray } from "./util.ts";
 import * as domTypes from "./dom_types.d.ts";
@@ -55,7 +56,6 @@ export class Response extends Body.Body implements domTypes.Response {
     if (!type) {
       type = "default";
     } else {
-      type = type;
       if (type == "error") {
         // spec: https://fetch.spec.whatwg.org/#concept-network-error
         status = 0;
@@ -144,12 +144,11 @@ export class Response extends Body.Body implements domTypes.Response {
       resBody = tees[1];
     }
 
-    const cloned = new Response(resBody, {
+    return new Response(resBody, {
       status: this.status,
       statusText: this.statusText,
       headers: new Headers(headersList),
     });
-    return cloned;
   }
 
   static redirect(url: URL | string, status: number): domTypes.Response {
@@ -260,7 +259,7 @@ export async function fetch(
   }
 
   let responseBody;
-  let responseInit: ResponseInit = {};
+  let responseInit: domTypes.ResponseInit = {};
   while (remRedirectCount) {
     const fetchResponse = await sendFetchReq(url, method, headers, body);
 
diff --git a/cli/js/web/fetch/multipart.ts b/cli/js/web/fetch/multipart.ts
index 654d4a0ea..a632d8600 100644
--- a/cli/js/web/fetch/multipart.ts
+++ b/cli/js/web/fetch/multipart.ts
@@ -19,12 +19,9 @@ interface MultipartHeaders {
 
 export class MultipartBuilder {
   readonly boundary: string;
-  readonly formData: FormData;
-  readonly writer: Buffer;
-  constructor(formData: FormData, boundary?: string) {
+  readonly writer = new Buffer();
+  constructor(readonly formData: FormData, boundary?: string) {
     this.boundary = boundary ?? this.#createBoundary();
-    this.formData = formData;
-    this.writer = new Buffer();
   }
 
   getContentType(): string {
diff --git a/cli/js/web/form_data.ts b/cli/js/web/form_data.ts
index 155f40771..2566943f0 100644
--- a/cli/js/web/form_data.ts
+++ b/cli/js/web/form_data.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import * as blob from "./blob.ts";
 import * as domFile from "./dom_file.ts";
 import { DomIterableMixin } from "./dom_iterable.ts";
@@ -96,10 +97,13 @@ class FormDataBase {
           if (value instanceof domFile.DomFileImpl) {
             this[dataSymbol][i][1] = value;
           } else if (value instanceof blob.DenoBlob) {
-            const dfile = new domFile.DomFileImpl([value], filename || "blob", {
-              type: value.type,
-            });
-            this[dataSymbol][i][1] = dfile;
+            this[dataSymbol][i][1] = new domFile.DomFileImpl(
+              [value],
+              filename || "blob",
+              {
+                type: value.type,
+              }
+            );
           } else {
             this[dataSymbol][i][1] = String(value);
           }
diff --git a/cli/js/web/headers.ts b/cli/js/web/headers.ts
index 9e0a70f0d..5fd6abc44 100644
--- a/cli/js/web/headers.ts
+++ b/cli/js/web/headers.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { DomIterableMixin } from "./dom_iterable.ts";
 import { requiredArguments } from "./util.ts";
 import { customInspect } from "./console.ts";
diff --git a/cli/js/web/performance.ts b/cli/js/web/performance.ts
index 7077b1edb..67f8f1b6c 100644
--- a/cli/js/web/performance.ts
+++ b/cli/js/web/performance.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { now as opNow } from "../ops/timers.ts";
 
 export class Performance {
diff --git a/cli/js/web/promise.ts b/cli/js/web/promise.ts
index b00c0786f..a24e8ed51 100644
--- a/cli/js/web/promise.ts
+++ b/cli/js/web/promise.ts
@@ -1,7 +1,9 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 export enum PromiseState {
-  Pending = 0,
-  Fulfilled = 1,
-  Rejected = 2,
+  Pending,
+  Fulfilled,
+  Rejected,
 }
 
 export type PromiseDetails<T> = [PromiseState, T | undefined];
diff --git a/cli/js/web/request.ts b/cli/js/web/request.ts
index 286aaff56..a9dcce2de 100644
--- a/cli/js/web/request.ts
+++ b/cli/js/web/request.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import * as body from "./body.ts";
 import * as domTypes from "./dom_types.d.ts";
 import { ReadableStreamImpl } from "./streams/readable_stream.ts";
@@ -128,12 +129,11 @@ export class Request extends body.Body implements domTypes.Request {
       body2 = tees[1];
     }
 
-    const cloned = new Request(this.url, {
+    return new Request(this.url, {
       body: body2,
       method: this.method,
       headers: new Headers(headersList),
       credentials: this.credentials,
     });
-    return cloned;
   }
 }
diff --git a/cli/js/web/streams/internals.ts b/cli/js/web/streams/internals.ts
index d0d35a1c3..3fbfb7735 100644
--- a/cli/js/web/streams/internals.ts
+++ b/cli/js/web/streams/internals.ts
@@ -5,7 +5,6 @@
 //
 // There are some parts that are not fully implemented, and there are some
 // comments which point to steps of the specification that are not implemented.
-//
 
 /* eslint-disable @typescript-eslint/no-explicit-any,require-await */
 import { ReadableByteStreamControllerImpl } from "./readable_byte_stream_controller.ts";
@@ -62,7 +61,7 @@ export interface ReadableStreamGenericReader<R = any>
 export interface ReadableStreamAsyncIterator<T = any> extends AsyncIterator<T> {
   [sym.asyncIteratorReader]: ReadableStreamDefaultReaderImpl<T>;
   [sym.preventCancel]: boolean;
-  return(value?: any | PromiseLike<any>): Promise<IteratorResult<T, any>>;
+  return(value?: any | PromiseLike<any>): Promise<IteratorResult<T>>;
 }
 
 export function acquireReadableStreamDefaultReader<T>(
@@ -97,6 +96,7 @@ function createAlgorithmFromUnderlyingMethod<
   algoArgCount: 0,
   ...extraArgs: any[]
 ): () => Promise<void>;
+
 function createAlgorithmFromUnderlyingMethod<
   O extends UnderlyingByteSource | UnderlyingSource | Transformer,
   P extends keyof O
@@ -317,79 +317,72 @@ function isFiniteNonNegativeNumber(v: unknown): v is number {
 export function isReadableByteStreamController(
   x: unknown
 ): x is ReadableByteStreamControllerImpl {
-  return typeof x !== "object" ||
+  return !(
+    typeof x !== "object" ||
     x === null ||
     !(sym.controlledReadableByteStream in x)
-    ? false
-    : true;
+  );
 }
 
 export function isReadableStream(x: unknown): x is ReadableStreamImpl {
-  return typeof x !== "object" ||
+  return !(
+    typeof x !== "object" ||
     x === null ||
     !(sym.readableStreamController in x)
-    ? false
-    : true;
+  );
 }
 
 export function isReadableStreamAsyncIterator(
   x: unknown
-): x is ReadableStreamAsyncIterator<any> {
+): x is ReadableStreamAsyncIterator {
   if (typeof x !== "object" || x === null) {
     return false;
   }
-  if (!(sym.asyncIteratorReader in x)) {
-    return false;
-  }
-  return true;
+  return sym.asyncIteratorReader in x;
 }
 
 export function isReadableStreamDefaultController(
   x: unknown
 ): x is ReadableStreamDefaultControllerImpl {
-  return typeof x !== "object" ||
+  return !(
+    typeof x !== "object" ||
     x === null ||
     !(sym.controlledReadableStream in x)
-    ? false
-    : true;
+  );
 }
 
 export function isReadableStreamDefaultReader<T>(
   x: unknown
 ): x is ReadableStreamDefaultReaderImpl<T> {
-  return typeof x !== "object" || x === null || !(sym.readRequests in x)
-    ? false
-    : true;
+  return !(typeof x !== "object" || x === null || !(sym.readRequests in x));
 }
 
 export function isReadableStreamLocked(stream: ReadableStreamImpl): boolean {
   assert(isReadableStream(stream));
-  return stream[sym.reader] ? true : false;
+  return !!stream[sym.reader];
 }
 
 export function isReadableStreamDisturbed(stream: ReadableStream): boolean {
   assert(isReadableStream(stream));
-  return stream[sym.disturbed] ? true : false;
+  return !!stream[sym.disturbed];
 }
 
-export function isTransformStream(
-  x: unknown
-): x is TransformStreamImpl<any, any> {
-  return typeof x !== "object" ||
+export function isTransformStream(x: unknown): x is TransformStreamImpl {
+  return !(
+    typeof x !== "object" ||
     x === null ||
     !(sym.transformStreamController in x)
-    ? false
-    : true;
+  );
 }
 
 export function isTransformStreamDefaultController(
   x: unknown
-): x is TransformStreamDefaultControllerImpl<any, any> {
-  return typeof x !== "object" ||
+): x is TransformStreamDefaultControllerImpl {
+  return !(
+    typeof x !== "object" ||
     x === null ||
     !(sym.controlledTransformStream in x)
-    ? false
-    : true;
+  );
 }
 
 export function isUnderlyingByteSource(
@@ -401,37 +394,36 @@ export function isUnderlyingByteSource(
 }
 
 export function isWritableStream(x: unknown): x is WritableStreamImpl {
-  return typeof x !== "object" ||
+  return !(
+    typeof x !== "object" ||
     x === null ||
     !(sym.writableStreamController in x)
-    ? false
-    : true;
+  );
 }
 
 export function isWritableStreamDefaultController(
   x: unknown
 ): x is WritableStreamDefaultControllerImpl<any> {
-  return typeof x !== "object" ||
+  return !(
+    typeof x !== "object" ||
     x === null ||
     !(sym.controlledWritableStream in x)
-    ? false
-    : true;
+  );
 }
 
 export function isWritableStreamDefaultWriter(
   x: unknown
 ): x is WritableStreamDefaultWriterImpl<any> {
-  return typeof x !== "object" || x === null || !(sym.ownerWritableStream in x)
-    ? false
-    : true;
+  return !(
+    typeof x !== "object" ||
+    x === null ||
+    !(sym.ownerWritableStream in x)
+  );
 }
 
 export function isWritableStreamLocked(stream: WritableStreamImpl): boolean {
   assert(isWritableStream(stream));
-  if (stream[sym.writer] === undefined) {
-    return false;
-  }
-  return true;
+  return stream[sym.writer] !== undefined;
 }
 
 export function makeSizeAlgorithmFromSizeFunction<T>(
@@ -476,10 +468,7 @@ function readableByteStreamControllerShouldCallPull(
   //            ReadableStreamGetNumReadIntoRequests(stream) > 0, return true.
   const desiredSize = readableByteStreamControllerGetDesiredSize(controller);
   assert(desiredSize !== null);
-  if (desiredSize > 0) {
-    return true;
-  }
-  return false;
+  return desiredSize > 0;
 }
 
 export function readableByteStreamControllerCallPullIfNeeded(
@@ -730,10 +719,7 @@ export function readableStreamDefaultControllerCanCloseOrEnqueue<T>(
   controller: ReadableStreamDefaultControllerImpl<T>
 ): boolean {
   const state = controller[sym.controlledReadableStream][sym.state];
-  if (!controller[sym.closeRequested] && state === "readable") {
-    return true;
-  }
-  return false;
+  return !controller[sym.closeRequested] && state === "readable";
 }
 
 export function readableStreamDefaultControllerClearAlgorithms<T>(
@@ -813,9 +799,7 @@ export function readableStreamDefaultControllerError<T>(
 function readableStreamDefaultControllerHasBackpressure<T>(
   controller: ReadableStreamDefaultControllerImpl<T>
 ): boolean {
-  return readableStreamDefaultControllerShouldCallPull(controller)
-    ? true
-    : false;
+  return readableStreamDefaultControllerShouldCallPull(controller);
 }
 
 function readableStreamDefaultControllerShouldCallPull<T>(
@@ -836,10 +820,7 @@ function readableStreamDefaultControllerShouldCallPull<T>(
   }
   const desiredSize = readableStreamDefaultControllerGetDesiredSize(controller);
   assert(desiredSize !== null);
-  if (desiredSize > 0) {
-    return true;
-  }
-  return false;
+  return desiredSize > 0;
 }
 
 export function readableStreamDefaultReaderRead<R>(
@@ -914,9 +895,7 @@ export function readableStreamHasDefaultReader(
   stream: ReadableStreamImpl
 ): boolean {
   const reader = stream[sym.reader];
-  return reader === undefined || !isReadableStreamDefaultReader(reader)
-    ? false
-    : true;
+  return !(reader === undefined || !isReadableStreamDefaultReader(reader));
 }
 
 export function readableStreamPipeTo<T>(
@@ -1927,13 +1906,10 @@ export function writableStreamClose<W>(
 export function writableStreamCloseQueuedOrInFlight<W>(
   stream: WritableStreamImpl<W>
 ): boolean {
-  if (
+  return !(
     stream[sym.closeRequest] === undefined &&
     stream[sym.inFlightCloseRequest] === undefined
-  ) {
-    return false;
-  }
-  return true;
+  );
 }
 
 function writableStreamDealWithRejection<W>(
@@ -2348,13 +2324,10 @@ function writableStreamFinishInFlightWriteWithError<W>(
 function writableStreamHasOperationMarkedInFlight<W>(
   stream: WritableStreamImpl<W>
 ): boolean {
-  if (
+  return !(
     stream[sym.inFlightWriteRequest] === undefined &&
     stream[sym.inFlightCloseRequest] === undefined
-  ) {
-    return false;
-  }
-  return true;
+  );
 }
 
 function writableStreamMarkCloseRequestInFlight<W>(
diff --git a/cli/js/web/text_encoding.ts b/cli/js/web/text_encoding.ts
index cd93d7a89..d225c6928 100644
--- a/cli/js/web/text_encoding.ts
+++ b/cli/js/web/text_encoding.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 // The following code is based off of text-encoding at:
 // https://github.com/inexorabletash/text-encoding
 //
@@ -151,8 +152,8 @@ interface Encoder {
 }
 
 class SingleByteDecoder implements Decoder {
-  #index: number[];
-  #fatal: boolean;
+  readonly #index: number[];
+  readonly #fatal: boolean;
 
   constructor(
     index: number[],
@@ -422,7 +423,7 @@ function isEitherArrayBuffer(x: any): x is EitherArrayBuffer {
 }
 
 export class TextDecoder {
-  #encoding: string;
+  readonly #encoding: string;
 
   get encoding(): string {
     return this.#encoding;
diff --git a/cli/js/web/timers.ts b/cli/js/web/timers.ts
index 74347ee7c..e8eacb402 100644
--- a/cli/js/web/timers.ts
+++ b/cli/js/web/timers.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { assert } from "../util.ts";
 import { startGlobalTimer, stopGlobalTimer } from "../ops/timers.ts";
 import { RBTree } from "../rbtree.ts";
diff --git a/cli/js/web/url.ts b/cli/js/web/url.ts
index 60690d46a..b12f6da75 100644
--- a/cli/js/web/url.ts
+++ b/cli/js/web/url.ts
@@ -24,7 +24,7 @@ const searchParamsMethods: Array<keyof URLSearchParams> = [
 const specialSchemes = ["ftp", "file", "http", "https", "ws", "wss"];
 
 // https://url.spec.whatwg.org/#special-scheme
-const schemePorts: { [key: string]: string } = {
+const schemePorts: Record<string, string> = {
   ftp: "21",
   file: "",
   http: "80",
@@ -179,8 +179,8 @@ function resolvePathFromBase(
 
   let driveLetterPrefix = "";
   if (build.os == "windows" && isFilePath) {
-    let driveLetter = "";
-    let baseDriveLetter = "";
+    let driveLetter: string;
+    let baseDriveLetter: string;
     [driveLetter, normalizedPath] = takePattern(
       normalizedPath,
       /^(\/[A-Za-z]:)(?=\/)/
@@ -214,7 +214,8 @@ function resolvePathFromBase(
 
 function isValidPort(value: string): boolean {
   // https://url.spec.whatwg.org/#port-state
-  if (value === "") true;
+  if (value === "") return true;
+
   const port = Number(value);
   return Number.isInteger(port) && port >= 0 && port <= MAX_PORT;
 }
@@ -409,7 +410,7 @@ export class URLImpl implements URL {
     let baseParts: URLParts | undefined;
     if (base) {
       baseParts = typeof base === "string" ? parse(base) : parts.get(base);
-      if (baseParts == undefined) {
+      if (baseParts === undefined) {
         throw new TypeError("Invalid base URL.");
       }
     }
diff --git a/cli/js/web/url_search_params.ts b/cli/js/web/url_search_params.ts
index 2abac3cd0..b4d199fbc 100644
--- a/cli/js/web/url_search_params.ts
+++ b/cli/js/web/url_search_params.ts
@@ -6,7 +6,7 @@ import { isIterable, requiredArguments } from "./util.ts";
 export const urls = new WeakMap<URLSearchParams, URL | null>();
 
 export class URLSearchParamsImpl implements URLSearchParams {
-  #params: Array<[string, string]> = [];
+  readonly #params: Array<[string, string]> = [];
 
   constructor(init: string | string[][] | Record<string, string> = "") {
     if (typeof init === "string") {
diff --git a/cli/js/web/workers.ts b/cli/js/web/workers.ts
index 1e0762932..cc40f104c 100644
--- a/cli/js/web/workers.ts
+++ b/cli/js/web/workers.ts
@@ -81,7 +81,7 @@ export interface WorkerOptions {
 
 export class WorkerImpl extends EventTarget implements Worker {
   readonly #id: number;
-  #name: string;
+  readonly #name: string;
   #terminated = false;
 
   public onerror?: (e: ErrorEvent) => void;