clean up code in cli/js (#6611)

38 files changed, 166 insertions, 142 deletions

diff --git a/cli/js/ops/dispatch_json.ts b/cli/js/ops/dispatch_json.ts
index 6a91f6a4f..cf6f5c095 100644
--- a/cli/js/ops/dispatch_json.ts
+++ b/cli/js/ops/dispatch_json.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import * as util from "../util.ts";
 import { core } from "../core.ts";
 import { ErrorKind, getErrorClass } from "../errors.ts";
@@ -18,9 +19,10 @@ interface JsonResponse {
 }
 
 // Using an object without a prototype because `Map` was causing GC problems.
-const promiseTable: {
-  [key: number]: util.Resolvable<JsonResponse>;
-} = Object.create(null);
+const promiseTable: Record<
+  number,
+  util.Resolvable<JsonResponse>
+> = Object.create(null);
 let _nextPromiseId = 1;
 
 function nextPromiseId(): number {
@@ -28,13 +30,11 @@ function nextPromiseId(): number {
 }
 
 function decode(ui8: Uint8Array): JsonResponse {
-  const s = core.decode(ui8);
-  return JSON.parse(s) as JsonResponse;
+  return JSON.parse(core.decode(ui8));
 }
 
 function encode(args: object): Uint8Array {
-  const s = JSON.stringify(args);
-  return core.encode(s);
+  return core.encode(JSON.stringify(args));
 }
 
 function unwrapResponse(res: JsonResponse): Ok {
@@ -80,7 +80,7 @@ export async function sendAsync(
   const promise = util.createResolvable<Ok>();
   const argsUi8 = encode(args);
   const buf = core.dispatchByName(opName, argsUi8, ...zeroCopy);
-  if (buf) {
+  if (buf != null) {
     // Sync result.
     const res = decode(buf);
     promise.resolve(res);
diff --git a/cli/js/ops/dispatch_minimal.ts b/cli/js/ops/dispatch_minimal.ts
index 0d1dac44e..ca50b00e9 100644
--- a/cli/js/ops/dispatch_minimal.ts
+++ b/cli/js/ops/dispatch_minimal.ts
@@ -1,13 +1,15 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import * as util from "../util.ts";
 import { core } from "../core.ts";
 import { TextDecoder } from "../web/text_encoding.ts";
 import { ErrorKind, errors, getErrorClass } from "../errors.ts";
 
 // Using an object without a prototype because `Map` was causing GC problems.
-const promiseTableMin: {
-  [key: number]: util.Resolvable<RecordMinimal>;
-} = Object.create(null);
+const promiseTableMin: Record<
+  number,
+  util.Resolvable<RecordMinimal>
+> = Object.create(null);
 
 // Note it's important that promiseId starts at 1 instead of 0, because sync
 // messages are indicated with promiseId 0. If we ever add wrap around logic for
@@ -93,7 +95,7 @@ export async function sendAsyncMinimal(
   scratch32[2] = 0; // result
   const promise = util.createResolvable<RecordMinimal>();
   const buf = core.dispatchByName(opName, scratchBytes, zeroCopy);
-  if (buf) {
+  if (buf != null) {
     const record = recordFromBufMinimal(buf);
     // Sync result.
     promise.resolve(record);
diff --git a/cli/js/ops/errors.ts b/cli/js/ops/errors.ts
index bd3e6d809..c6c26b8ba 100644
--- a/cli/js/ops/errors.ts
+++ b/cli/js/ops/errors.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { DiagnosticItem } from "../diagnostics.ts";
 import { sendSync } from "./dispatch_json.ts";
 
@@ -13,12 +14,7 @@ export interface Location {
 }
 
 export function applySourceMap(location: Location): Location {
-  const { fileName, lineNumber, columnNumber } = location;
-  const res = sendSync("op_apply_source_map", {
-    fileName,
-    lineNumber: lineNumber,
-    columnNumber: columnNumber,
-  });
+  const res = sendSync("op_apply_source_map", location);
   return {
     fileName: res.fileName,
     lineNumber: res.lineNumber,
diff --git a/cli/js/ops/fetch.ts b/cli/js/ops/fetch.ts
index 290376c86..2f881cc02 100644
--- a/cli/js/ops/fetch.ts
+++ b/cli/js/ops/fetch.ts
@@ -17,10 +17,10 @@ export interface FetchResponse {
 
 export function fetch(
   args: FetchRequest,
-  body: ArrayBufferView | undefined
+  body?: ArrayBufferView
 ): Promise<FetchResponse> {
-  let zeroCopy = undefined;
-  if (body) {
+  let zeroCopy;
+  if (body != null) {
     zeroCopy = new Uint8Array(body.buffer, body.byteOffset, body.byteLength);
   }
 
diff --git a/cli/js/ops/fs/chmod.ts b/cli/js/ops/fs/chmod.ts
index 76a3c8f49..a2236935b 100644
--- a/cli/js/ops/fs/chmod.ts
+++ b/cli/js/ops/fs/chmod.ts
@@ -1,13 +1,12 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { pathFromURL } from "../../util.ts";
 
 export function chmodSync(path: string | URL, mode: number): void {
-  path = pathFromURL(path);
-  sendSync("op_chmod", { path, mode });
+  sendSync("op_chmod", { path: pathFromURL(path), mode });
 }
 
 export async function chmod(path: string | URL, mode: number): Promise<void> {
-  path = pathFromURL(path);
-  await sendAsync("op_chmod", { path, mode });
+  await sendAsync("op_chmod", { path: pathFromURL(path), mode });
 }
diff --git a/cli/js/ops/fs/chown.ts b/cli/js/ops/fs/chown.ts
index 3afe07f16..52735e097 100644
--- a/cli/js/ops/fs/chown.ts
+++ b/cli/js/ops/fs/chown.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { pathFromURL } from "../../util.ts";
 
@@ -7,8 +8,7 @@ export function chownSync(
   uid: number | null,
   gid: number | null
 ): void {
-  path = pathFromURL(path);
-  sendSync("op_chown", { path, uid, gid });
+  sendSync("op_chown", { path: pathFromURL(path), uid, gid });
 }
 
 export async function chown(
@@ -16,6 +16,5 @@ export async function chown(
   uid: number | null,
   gid: number | null
 ): Promise<void> {
-  path = pathFromURL(path);
-  await sendAsync("op_chown", { path, uid, gid });
+  await sendAsync("op_chown", { path: pathFromURL(path), uid, gid });
 }
diff --git a/cli/js/ops/fs/copy_file.ts b/cli/js/ops/fs/copy_file.ts
index 6bbb3f599..fcb147bdd 100644
--- a/cli/js/ops/fs/copy_file.ts
+++ b/cli/js/ops/fs/copy_file.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { pathFromURL } from "../../util.ts";
 
@@ -6,18 +7,18 @@ export function copyFileSync(
   fromPath: string | URL,
   toPath: string | URL
 ): void {
-  fromPath = pathFromURL(fromPath);
-  toPath = pathFromURL(toPath);
-
-  sendSync("op_copy_file", { from: fromPath, to: toPath });
+  sendSync("op_copy_file", {
+    from: pathFromURL(fromPath),
+    to: pathFromURL(toPath),
+  });
 }
 
 export async function copyFile(
   fromPath: string | URL,
   toPath: string | URL
 ): Promise<void> {
-  fromPath = pathFromURL(fromPath);
-  toPath = pathFromURL(toPath);
-
-  await sendAsync("op_copy_file", { from: fromPath, to: toPath });
+  await sendAsync("op_copy_file", {
+    from: pathFromURL(fromPath),
+    to: pathFromURL(toPath),
+  });
 }
diff --git a/cli/js/ops/fs/dir.ts b/cli/js/ops/fs/dir.ts
index 14b6240ed..dbf468c62 100644
--- a/cli/js/ops/fs/dir.ts
+++ b/cli/js/ops/fs/dir.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync } from "../dispatch_json.ts";
 
 export function cwd(): string {
diff --git a/cli/js/ops/fs/link.ts b/cli/js/ops/fs/link.ts
index 92fb58834..05ff358ef 100644
--- a/cli/js/ops/fs/link.ts
+++ b/cli/js/ops/fs/link.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 export function linkSync(oldpath: string, newpath: string): void {
diff --git a/cli/js/ops/fs/make_temp.ts b/cli/js/ops/fs/make_temp.ts
index 85dea5f20..3996744d1 100644
--- a/cli/js/ops/fs/make_temp.ts
+++ b/cli/js/ops/fs/make_temp.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 export interface MakeTempOptions {
diff --git a/cli/js/ops/fs/mkdir.ts b/cli/js/ops/fs/mkdir.ts
index 374a00d83..61ea1c218 100644
--- a/cli/js/ops/fs/mkdir.ts
+++ b/cli/js/ops/fs/mkdir.ts
@@ -1,11 +1,21 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
-type MkdirArgs = { path: string; recursive: boolean; mode?: number };
+export interface MkdirOptions {
+  recursive?: boolean;
+  mode?: number;
+}
+
+interface MkdirArgs {
+  path: string;
+  recursive: boolean;
+  mode?: number;
+}
 
 function mkdirArgs(path: string, options?: MkdirOptions): MkdirArgs {
   const args: MkdirArgs = { path, recursive: false };
-  if (options) {
+  if (options != null) {
     if (typeof options.recursive == "boolean") {
       args.recursive = options.recursive;
     }
@@ -16,11 +26,6 @@ function mkdirArgs(path: string, options?: MkdirOptions): MkdirArgs {
   return args;
 }
 
-export interface MkdirOptions {
-  recursive?: boolean;
-  mode?: number;
-}
-
 export function mkdirSync(path: string, options?: MkdirOptions): void {
   sendSync("op_mkdir", mkdirArgs(path, options));
 }
diff --git a/cli/js/ops/fs/open.ts b/cli/js/ops/fs/open.ts
index 3742d0b52..edd52c376 100644
--- a/cli/js/ops/fs/open.ts
+++ b/cli/js/ops/fs/open.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { pathFromURL } from "../../util.ts";
 
@@ -18,8 +19,7 @@ export interface OpenOptions {
 
 export function openSync(path: string | URL, options: OpenOptions): number {
   const mode: number | undefined = options?.mode;
-  path = pathFromURL(path);
-  return sendSync("op_open", { path, options, mode });
+  return sendSync("op_open", { path: pathFromURL(path), options, mode });
 }
 
 export function open(
@@ -27,10 +27,5 @@ export function open(
   options: OpenOptions
 ): Promise<number> {
   const mode: number | undefined = options?.mode;
-  path = pathFromURL(path);
-  return sendAsync("op_open", {
-    path,
-    options,
-    mode,
-  });
+  return sendAsync("op_open", { path: pathFromURL(path), options, mode });
 }
diff --git a/cli/js/ops/fs/read_dir.ts b/cli/js/ops/fs/read_dir.ts
index 09c5d1c12..6ffe6116e 100644
--- a/cli/js/ops/fs/read_dir.ts
+++ b/cli/js/ops/fs/read_dir.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { pathFromURL } from "../../util.ts";
 
@@ -18,13 +19,13 @@ function res(response: ReadDirResponse): DirEntry[] {
 }
 
 export function readDirSync(path: string | URL): Iterable<DirEntry> {
-  path = pathFromURL(path);
-  return res(sendSync("op_read_dir", { path }))[Symbol.iterator]();
+  return res(sendSync("op_read_dir", { path: pathFromURL(path) }))[
+    Symbol.iterator
+  ]();
 }
 
 export function readDir(path: string | URL): AsyncIterable<DirEntry> {
-  path = pathFromURL(path);
-  const array = sendAsync("op_read_dir", { path }).then(res);
+  const array = sendAsync("op_read_dir", { path: pathFromURL(path) }).then(res);
   return {
     async *[Symbol.asyncIterator](): AsyncIterableIterator<DirEntry> {
       yield* await array;
diff --git a/cli/js/ops/fs/read_link.ts b/cli/js/ops/fs/read_link.ts
index bcd27ccb7..33fef7e36 100644
--- a/cli/js/ops/fs/read_link.ts
+++ b/cli/js/ops/fs/read_link.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 export function readLinkSync(path: string): string {
diff --git a/cli/js/ops/fs/real_path.ts b/cli/js/ops/fs/real_path.ts
index ab95b9583..c424d99bc 100644
--- a/cli/js/ops/fs/real_path.ts
+++ b/cli/js/ops/fs/real_path.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 export function realPathSync(path: string): string {
diff --git a/cli/js/ops/fs/remove.ts b/cli/js/ops/fs/remove.ts
index d1a8702f1..52f4cad40 100644
--- a/cli/js/ops/fs/remove.ts
+++ b/cli/js/ops/fs/remove.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { pathFromURL } from "../../util.ts";
 
@@ -10,14 +11,18 @@ export function removeSync(
   path: string | URL,
   options: RemoveOptions = {}
 ): void {
-  path = pathFromURL(path);
-  sendSync("op_remove", { path, recursive: !!options.recursive });
+  sendSync("op_remove", {
+    path: pathFromURL(path),
+    recursive: !!options.recursive,
+  });
 }
 
 export async function remove(
   path: string | URL,
   options: RemoveOptions = {}
 ): Promise<void> {
-  path = pathFromURL(path);
-  await sendAsync("op_remove", { path, recursive: !!options.recursive });
+  await sendAsync("op_remove", {
+    path: pathFromURL(path),
+    recursive: !!options.recursive,
+  });
 }
diff --git a/cli/js/ops/fs/rename.ts b/cli/js/ops/fs/rename.ts
index 9f02c8bc0..f0789d3eb 100644
--- a/cli/js/ops/fs/rename.ts
+++ b/cli/js/ops/fs/rename.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 export function renameSync(oldpath: string, newpath: string): void {
diff --git a/cli/js/ops/fs/seek.ts b/cli/js/ops/fs/seek.ts
index c7e4c9172..2e23e084b 100644
--- a/cli/js/ops/fs/seek.ts
+++ b/cli/js/ops/fs/seek.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { SeekMode } from "../../io.ts";
 
diff --git a/cli/js/ops/fs/stat.ts b/cli/js/ops/fs/stat.ts
index 402adeafc..f444190fd 100644
--- a/cli/js/ops/fs/stat.ts
+++ b/cli/js/ops/fs/stat.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 import { build } from "../../build.ts";
 import { pathFromURL } from "../../util.ts";
@@ -44,7 +45,7 @@ export interface StatResponse {
 
 // @internal
 export function parseFileInfo(response: StatResponse): FileInfo {
-  const isUnix = build.os === "darwin" || build.os === "linux";
+  const unix = build.os === "darwin" || build.os === "linux";
   return {
     isFile: response.isFile,
     isDirectory: response.isDirectory,
@@ -54,15 +55,15 @@ export function parseFileInfo(response: StatResponse): FileInfo {
     atime: response.atime != null ? new Date(response.atime) : null,
     birthtime: response.birthtime != null ? new Date(response.birthtime) : null,
     // Only non-null if on Unix
-    dev: isUnix ? response.dev : null,
-    ino: isUnix ? response.ino : null,
-    mode: isUnix ? response.mode : null,
-    nlink: isUnix ? response.nlink : null,
-    uid: isUnix ? response.uid : null,
-    gid: isUnix ? response.gid : null,
-    rdev: isUnix ? response.rdev : null,
-    blksize: isUnix ? response.blksize : null,
-    blocks: isUnix ? response.blocks : null,
+    dev: unix ? response.dev : null,
+    ino: unix ? response.ino : null,
+    mode: unix ? response.mode : null,
+    nlink: unix ? response.nlink : null,
+    uid: unix ? response.uid : null,
+    gid: unix ? response.gid : null,
+    rdev: unix ? response.rdev : null,
+    blksize: unix ? response.blksize : null,
+    blocks: unix ? response.blocks : null,
   };
 }
 
@@ -75,37 +76,33 @@ export async function fstat(rid: number): Promise<FileInfo> {
 }
 
 export async function lstat(path: string | URL): Promise<FileInfo> {
-  path = pathFromURL(path);
-  const res = (await sendAsync("op_stat", {
-    path,
+  const res = await sendAsync("op_stat", {
+    path: pathFromURL(path),
     lstat: true,
-  })) as StatResponse;
+  });
   return parseFileInfo(res);
 }
 
 export function lstatSync(path: string | URL): FileInfo {
-  path = pathFromURL(path);
   const res = sendSync("op_stat", {
-    path,
+    path: pathFromURL(path),
     lstat: true,
-  }) as StatResponse;
+  });
   return parseFileInfo(res);
 }
 
 export async function stat(path: string | URL): Promise<FileInfo> {
-  path = pathFromURL(path);
-  const res = (await sendAsync("op_stat", {
-    path,
+  const res = await sendAsync("op_stat", {
+    path: pathFromURL(path),
     lstat: false,
-  })) as StatResponse;
+  });
   return parseFileInfo(res);
 }
 
 export function statSync(path: string | URL): FileInfo {
-  path = pathFromURL(path);
   const res = sendSync("op_stat", {
-    path,
+    path: pathFromURL(path),
     lstat: false,
-  }) as StatResponse;
+  });
   return parseFileInfo(res);
 }
diff --git a/cli/js/ops/fs/symlink.ts b/cli/js/ops/fs/symlink.ts
index fde611b55..7d4741928 100644
--- a/cli/js/ops/fs/symlink.ts
+++ b/cli/js/ops/fs/symlink.ts
@@ -1,14 +1,15 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
-export type symlinkOptions = {
+export interface SymlinkOptions {
   type: "file" | "dir";
-};
+}
 
 export function symlinkSync(
   oldpath: string,
   newpath: string,
-  options?: symlinkOptions
+  options?: SymlinkOptions
 ): void {
   sendSync("op_symlink", { oldpath, newpath, options });
 }
@@ -16,7 +17,7 @@ export function symlinkSync(
 export async function symlink(
   oldpath: string,
   newpath: string,
-  options?: symlinkOptions
+  options?: SymlinkOptions
 ): Promise<void> {
   await sendAsync("op_symlink", { oldpath, newpath, options });
 }
diff --git a/cli/js/ops/fs/sync.ts b/cli/js/ops/fs/sync.ts
index 567aab55b..7f208b8bd 100644
--- a/cli/js/ops/fs/sync.ts
+++ b/cli/js/ops/fs/sync.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 export function fdatasyncSync(rid: number): void {
diff --git a/cli/js/ops/fs/truncate.ts b/cli/js/ops/fs/truncate.ts
index 2b805e5ac..d18e5d9d9 100644
--- a/cli/js/ops/fs/truncate.ts
+++ b/cli/js/ops/fs/truncate.ts
@@ -1,12 +1,9 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 function coerceLen(len?: number): number {
-  if (!len) {
-    return 0;
-  }
-
-  if (len < 0) {
+  if (len == null || len < 0) {
     return 0;
   }
 
diff --git a/cli/js/ops/fs/umask.ts b/cli/js/ops/fs/umask.ts
index 38bf8ff6c..fbc94091e 100644
--- a/cli/js/ops/fs/umask.ts
+++ b/cli/js/ops/fs/umask.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync } from "../dispatch_json.ts";
 
 export function umask(mask?: number): number {
diff --git a/cli/js/ops/fs/utime.ts b/cli/js/ops/fs/utime.ts
index 2755a7e96..fa86038c6 100644
--- a/cli/js/ops/fs/utime.ts
+++ b/cli/js/ops/fs/utime.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
 function toSecondsFromEpoch(v: number | Date): number {
diff --git a/cli/js/ops/fs_events.ts b/cli/js/ops/fs_events.ts
index 9d72cb898..fb78c6196 100644
--- a/cli/js/ops/fs_events.ts
+++ b/cli/js/ops/fs_events.ts
@@ -1,4 +1,5 @@
-// Copyright 2019 the Deno authors. All rights reserved. MIT license.
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "./dispatch_json.ts";
 import { close } from "./resources.ts";
 
@@ -7,10 +8,14 @@ export interface FsEvent {
   paths: string[];
 }
 
+interface FsWatcherOptions {
+  recursive: boolean;
+}
+
 class FsWatcher implements AsyncIterableIterator<FsEvent> {
   readonly rid: number;
 
-  constructor(paths: string[], options: { recursive: boolean }) {
+  constructor(paths: string[], options: FsWatcherOptions) {
     const { recursive } = options;
     this.rid = sendSync("op_fs_events_open", { recursive, paths });
   }
@@ -33,7 +38,7 @@ class FsWatcher implements AsyncIterableIterator<FsEvent> {
 
 export function watchFs(
   paths: string | string[],
-  options = { recursive: true }
+  options: FsWatcherOptions = { recursive: true }
 ): AsyncIterableIterator<FsEvent> {
   return new FsWatcher(Array.isArray(paths) ? paths : [paths], options);
 }
diff --git a/cli/js/ops/get_random_values.ts b/cli/js/ops/get_random_values.ts
index 1dc56b698..95e4602e6 100644
--- a/cli/js/ops/get_random_values.ts
+++ b/cli/js/ops/get_random_values.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync } from "./dispatch_json.ts";
 import { assert } from "../util.ts";
 
diff --git a/cli/js/ops/io.ts b/cli/js/ops/io.ts
index cc3d1d170..ecd1269d5 100644
--- a/cli/js/ops/io.ts
+++ b/cli/js/ops/io.ts
@@ -3,50 +3,48 @@
 import { sendAsyncMinimal, sendSyncMinimal } from "./dispatch_minimal.ts";
 
 export function readSync(rid: number, buffer: Uint8Array): number | null {
-  if (buffer.length == 0) {
+  if (buffer.length === 0) {
     return 0;
   }
+
   const nread = sendSyncMinimal("op_read", rid, buffer);
   if (nread < 0) {
     throw new Error("read error");
-  } else if (nread == 0) {
-    return null;
-  } else {
-    return nread;
   }
+
+  return nread === 0 ? null : nread;
 }
 
 export async function read(
   rid: number,
   buffer: Uint8Array
 ): Promise<number | null> {
-  if (buffer.length == 0) {
+  if (buffer.length === 0) {
     return 0;
   }
+
   const nread = await sendAsyncMinimal("op_read", rid, buffer);
   if (nread < 0) {
     throw new Error("read error");
-  } else if (nread == 0) {
-    return null;
-  } else {
-    return nread;
   }
+
+  return nread === 0 ? null : nread;
 }
 
 export function writeSync(rid: number, data: Uint8Array): number {
   const result = sendSyncMinimal("op_write", rid, data);
   if (result < 0) {
     throw new Error("write error");
-  } else {
-    return result;
   }
+
+  return result;
 }
 
 export async function write(rid: number, data: Uint8Array): Promise<number> {
   const result = await sendAsyncMinimal("op_write", rid, data);
   if (result < 0) {
     throw new Error("write error");
-  } else {
-    return result;
   }
+
+  return result;
 }
diff --git a/cli/js/ops/net.ts b/cli/js/ops/net.ts
index 98ee71ff8..05b1bc2cd 100644
--- a/cli/js/ops/net.ts
+++ b/cli/js/ops/net.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "./dispatch_json.ts";
 
 export interface NetAddr {
@@ -18,7 +19,7 @@ export enum ShutdownMode {
   // See http://man7.org/linux/man-pages/man2/shutdown.2.html
   // Corresponding to SHUT_RD, SHUT_WR, SHUT_RDWR
   Read = 0,
-  Write,
+  Write = 1,
   ReadWrite, // unused
 }
 
@@ -80,10 +81,6 @@ export type SendRequest = {
   rid: number;
 } & Addr;
 
-export async function send(
-  args: SendRequest,
-  zeroCopy: Uint8Array
-): Promise<number> {
-  const byteLength = await sendAsync("op_datagram_send", args, zeroCopy);
-  return byteLength;
+export function send(args: SendRequest, zeroCopy: Uint8Array): Promise<number> {
+  return sendAsync("op_datagram_send", args, zeroCopy);
 }
diff --git a/cli/js/ops/os.ts b/cli/js/ops/os.ts
index 696c9f10b..50234ee4b 100644
--- a/cli/js/ops/os.ts
+++ b/cli/js/ops/os.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync } from "./dispatch_json.ts";
 
 export function loadavg(): number[] {
@@ -32,7 +33,7 @@ function deleteEnv(key: string): void {
 
 export const env = {
   get: getEnv,
-  toObject(): { [key: string]: string } {
+  toObject(): Record<string, string> {
     return sendSync("op_env");
   },
   set: setEnv,
diff --git a/cli/js/ops/permissions.ts b/cli/js/ops/permissions.ts
index 783b1b297..dfe8c4834 100644
--- a/cli/js/ops/permissions.ts
+++ b/cli/js/ops/permissions.ts
@@ -1,9 +1,7 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { sendSync } from "./dispatch_json.ts";
 
-// TODO(bartlomieju): duplicated in `cli/js/permissions.ts` as
-// `PermissionState
-export type PermissionResponse = "granted" | "denied" | "prompt";
+import { sendSync } from "./dispatch_json.ts";
+import { PermissionState } from "../permissions.ts";
 
 interface PermissionRequest {
   name: string;
@@ -11,14 +9,14 @@ interface PermissionRequest {
   path?: string;
 }
 
-export function query(desc: PermissionRequest): PermissionResponse {
+export function query(desc: PermissionRequest): PermissionState {
   return sendSync("op_query_permission", desc).state;
 }
 
-export function revoke(desc: PermissionRequest): PermissionResponse {
+export function revoke(desc: PermissionRequest): PermissionState {
   return sendSync("op_revoke_permission", desc).state;
 }
 
-export function request(desc: PermissionRequest): PermissionResponse {
+export function request(desc: PermissionRequest): PermissionState {
   return sendSync("op_request_permission", desc).state;
 }
diff --git a/cli/js/ops/plugins.ts b/cli/js/ops/plugins.ts
index e4593afbb..787fd799b 100644
--- a/cli/js/ops/plugins.ts
+++ b/cli/js/ops/plugins.ts
@@ -1,6 +1,7 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync } from "./dispatch_json.ts";
 
 export function openPlugin(filename: string): number {
-  const rid = sendSync("op_open_plugin", { filename });
-  return rid;
+  return sendSync("op_open_plugin", { filename });
 }
diff --git a/cli/js/ops/process.ts b/cli/js/ops/process.ts
index 39c6eb8b7..86a0c9a71 100644
--- a/cli/js/ops/process.ts
+++ b/cli/js/ops/process.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "./dispatch_json.ts";
 import { assert } from "../util.ts";
 
diff --git a/cli/js/ops/resources.ts b/cli/js/ops/resources.ts
index dacdaa659..ffcdb553e 100644
--- a/cli/js/ops/resources.ts
+++ b/cli/js/ops/resources.ts
@@ -1,9 +1,8 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync } from "./dispatch_json.ts";
 
-export interface ResourceMap {
-  [rid: number]: string;
-}
+export type ResourceMap = Record<number, string>;
 
 export function resources(): ResourceMap {
   const res = sendSync("op_resources") as Array<[number, string]>;
diff --git a/cli/js/ops/signal.ts b/cli/js/ops/signal.ts
index 09c178105..15093a3c4 100644
--- a/cli/js/ops/signal.ts
+++ b/cli/js/ops/signal.ts
@@ -1,11 +1,20 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "./dispatch_json.ts";
 
-export function bindSignal(signo: number): { rid: number } {
+interface BindSignalResponse {
+  rid: number;
+}
+
+interface PollSignalResponse {
+  done: boolean;
+}
+
+export function bindSignal(signo: number): BindSignalResponse {
   return sendSync("op_signal_bind", { signo });
 }
 
-export function pollSignal(rid: number): Promise<{ done: boolean }> {
+export function pollSignal(rid: number): Promise<PollSignalResponse> {
   return sendAsync("op_signal_poll", { rid });
 }
 
diff --git a/cli/js/ops/timers.ts b/cli/js/ops/timers.ts
index 1a7081df0..2fdbd6851 100644
--- a/cli/js/ops/timers.ts
+++ b/cli/js/ops/timers.ts
@@ -1,6 +1,12 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync, sendAsync } from "./dispatch_json.ts";
 
+interface NowResponse {
+  seconds: number;
+  subsecNanos: number;
+}
+
 export function stopGlobalTimer(): void {
   sendSync("op_global_timer_stop");
 }
@@ -9,11 +15,6 @@ export async function startGlobalTimer(timeout: number): Promise<void> {
   await sendAsync("op_global_timer", { timeout });
 }
 
-interface NowResponse {
-  seconds: number;
-  subsecNanos: number;
-}
-
 export function now(): NowResponse {
   return sendSync("op_now");
 }
diff --git a/cli/js/ops/tls.ts b/cli/js/ops/tls.ts
index 60ec8846c..b278c2d75 100644
--- a/cli/js/ops/tls.ts
+++ b/cli/js/ops/tls.ts
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendAsync, sendSync } from "./dispatch_json.ts";
 
 export interface ConnectTLSRequest {
diff --git a/cli/js/ops/tty.ts b/cli/js/ops/tty.ts
index f848d2774..8899ca5b8 100644
--- a/cli/js/ops/tty.ts
+++ b/cli/js/ops/tty.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { sendSync } from "./dispatch_json.ts";
 
 export function isatty(rid: number): boolean {
@@ -5,8 +7,5 @@ export function isatty(rid: number): boolean {
 }
 
 export function setRaw(rid: number, mode: boolean): void {
-  sendSync("op_set_raw", {
-    rid,
-    mode,
-  });
+  sendSync("op_set_raw", { rid, mode });
 }
diff --git a/cli/js/ops/worker_host.ts b/cli/js/ops/worker_host.ts
index 11e268152..24e6b57ba 100644
--- a/cli/js/ops/worker_host.ts
+++ b/cli/js/ops/worker_host.ts
@@ -1,14 +1,19 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import { sendAsync, sendSync } from "./dispatch_json.ts";
 
+interface CreateWorkerResponse {
+  id: number;
+}
+
 export function createWorker(
   specifier: string,
   hasSourceCode: boolean,
   sourceCode: string,
   useDenoNamespace: boolean,
   name?: string
-): { id: number } {
+): CreateWorkerResponse {
   return sendSync("op_create_worker", {
     specifier,
     hasSourceCode,