Update eslint and @typescript-eslint (denoland/deno_std#621)

Original: c3fe858f98

.ci/template.linux.yml

@@ -1,5 +1,5 @@
 steps:
-  - bash: npm install eslint@5.16.0 typescript@$(TS_VERSION) @typescript-eslint/eslint-plugin@1.13.0 @typescript-eslint/parser@1.13.0 eslint-config-prettier
+  - bash: npm install eslint@$(ESLINT_VERSION) typescript@$(TS_VERSION) @typescript-eslint/eslint-plugin@$(TS_ESLINT_VERSION) @typescript-eslint/parser@$(TS_ESLINT_VERSION) eslint-config-prettier
   - template: ./template.unix.yml
-  - bash: npx eslint **/*.ts --max-warnings=0
+  - bash: npx eslint "**/*.ts" --max-warnings=0
   - template: ./template.common.yml

.ci/template.mac.yml

@@ -1,6 +1,8 @@
 steps:
-  - bash: npm install -g functional-red-black-tree
+  - task: NodeTool@0
-  - bash: npm -g install eslint@5.16.0 typescript@$(TS_VERSION) @typescript-eslint/eslint-plugin@1.13.0 @typescript-eslint/parser@1.13.0 eslint-config-prettier
+    inputs:
+      versionSpec: '10.x'
+  - bash: npm install eslint@$(ESLINT_VERSION) typescript@$(TS_VERSION) @typescript-eslint/eslint-plugin@$(TS_ESLINT_VERSION) @typescript-eslint/parser@$(TS_ESLINT_VERSION) eslint-config-prettier
   - template: ./template.unix.yml
-  - bash: eslint **/*.ts --max-warnings=0
+  - bash: npx eslint "**/*.ts" --max-warnings=0
   - template: ./template.common.yml

.ci/template.windows.yml

@@ -1,8 +1,8 @@
 steps:
-  - bash: npm install eslint@5.16.0 typescript@$(TS_VERSION) @typescript-eslint/eslint-plugin@1.13.0 @typescript-eslint/parser@1.13.0 eslint-config-prettier
+  - bash: npm install eslint@$(ESLINT_VERSION) typescript@$(TS_VERSION) @typescript-eslint/eslint-plugin@$(TS_ESLINT_VERSION) @typescript-eslint/parser@$(TS_ESLINT_VERSION) eslint-config-prettier
   - powershell: iwr https://deno.land/x/install/install.ps1 -out install.ps1; .\install.ps1 $(DENO_VERSION)
   - bash: echo "##vso[task.prependpath]C:\Users\VssAdministrator\.deno\\bin"
-  - bash: npx eslint **/*.ts --max-warnings=0
+  - bash: npx eslint "**/*.ts" --max-warnings=0
   - template: ./template.common.yml
     parameters:
       exe_suffix: ".exe"

.eslintignore

@@ -0,0 +1,4 @@
+/deno.d.ts
+/prettier/vendor
+**/testdata/
+

.eslintrc.json

@@ -2,7 +2,8 @@
   "root": true,
   "parser": "@typescript-eslint/parser",
   "parserOptions": {
-    "project": "./tsconfig.json"
+    "project": "./tsconfig.json",
+    "createDefaultProgram": true
   },
   "plugins": ["@typescript-eslint"],
   "extends": [
@@ -11,7 +12,7 @@
     "prettier/@typescript-eslint"
   ],
   "rules": {
-    "@typescript-eslint/array-type": ["error", "array-simple"],
+    "@typescript-eslint/array-type": ["error", { "default": "array-simple" }],
     "@typescript-eslint/explicit-member-accessibility": ["off"],
     "@typescript-eslint/no-non-null-assertion": ["off"],
     "@typescript-eslint/no-parameter-properties": ["off"],
@@ -19,6 +20,8 @@
       "error",
       { "argsIgnorePattern": "^_", "varsIgnorePattern": "_" }
     ],
+    "@typescript-eslint/ban-ts-ignore": ["off"],
+    "@typescript-eslint/no-empty-function": ["off"],
     "max-len": [
       "error",
       {

archive/tar.ts

@@ -96,7 +96,7 @@ function clean(length: number): Uint8Array {
 }
 
 function pad(num: number, bytes: number, base?: number): string {
-  var numString = num.toString(base || 8);
+  const numString = num.toString(base || 8);
   return "000000000000".substr(numString.length + 12 - bytes) + numString;
 }
 
@@ -328,7 +328,7 @@ export class Tar {
     // set meta data
     const info = opts.filePath && (await Deno.stat(opts.filePath));
 
-    let mode =
+    const mode =
         opts.fileMode || (info && info.mode) || parseInt("777", 8) & 0xfff,
       mtime =
         opts.mtime ||
@@ -385,8 +385,9 @@ export class Tar {
   getReader(): Deno.Reader {
     const readers: Deno.Reader[] = [];
     this.data.forEach((tarData): void => {
-      let { filePath, reader } = tarData,
+      let { reader } = tarData;
-        headerArr = formatHeader(tarData);
+      const { filePath } = tarData;
+      const headerArr = formatHeader(tarData);
       readers.push(new Deno.Buffer(headerArr));
       if (!reader) {
         reader = new FileReader(filePath!);

azure-pipelines.yml

@@ -1,6 +1,8 @@
 variables:
   DENO_VERSION: "v0.19.0"
   TS_VERSION: "3.4.5"
+  ESLINT_VERSION: "6.5.1"
+  TS_ESLINT_VERSION: "2.3.2"
 
 # TODO Try to get eslint to run under Deno, like prettier
 jobs:

bundle/test.ts

@@ -12,6 +12,7 @@ import { instantiate, load, ModuleMetaData } from "./utils.ts";
 /* eslint-disable @typescript-eslint/no-namespace */
 declare global {
   namespace globalThis {
+    // eslint-disable-next-line no-var
     var __results: [string, string] | undefined;
   }
 }

bundle/utils.ts

@@ -23,6 +23,7 @@ type Define = (
 /* eslint-disable @typescript-eslint/no-namespace */
 declare global {
   namespace globalThis {
+    // eslint-disable-next-line no-var
     var define: Define | undefined;
   }
 }

datetime/mod.ts

@@ -118,7 +118,7 @@ export function currentDayOfYear(): number {
  * @return IMF date formated string
  */
 export function toIMF(date: Date): string {
-  function dtPad(v: string, lPad: number = 2): string {
+  function dtPad(v: string, lPad = 2): string {
     return pad(v, lPad, { char: "0" });
   }
   const d = dtPad(date.getUTCDate().toString());

encoding/csv.ts

@@ -56,7 +56,7 @@ async function read(
   const tp = new TextProtoReader(reader);
   let line: string;
   let result: string[] = [];
-  let lineIndex = Startline;
+  const lineIndex = Startline;
 
   const r = await tp.readLine();
   if (r === Deno.EOF) return Deno.EOF;
@@ -229,7 +229,7 @@ export async function parse(
         throw `Error number of fields line:${i}`;
       }
       i++;
-      let out: Record<string, unknown> = {};
+      const out: Record<string, unknown> = {};
       for (let j = 0; j < e.length; j++) {
         const h = headers[j];
         if (h.parse) {

encoding/hex.ts

@@ -85,7 +85,7 @@ export function decode(
   dst: Uint8Array,
   src: Uint8Array
 ): [number, Error | void] {
-  var i = 0;
+  let i = 0;
   for (; i < Math.floor(src.length / 2); i++) {
     const [a, aOK] = fromHexChar(src[i * 2]);
     if (!aOK) {

encoding/toml.ts

@@ -64,8 +64,8 @@ class Parser {
       return line.match(/'''/) ? true : false;
     }
 
-    let merged = [],
+    const merged = [];
-      acc = [],
+    let acc = [],
       isLiteral = false,
       capture = false,
       captureType = "",
@@ -123,14 +123,14 @@ class Parser {
     this.tomlLines = merged;
   }
   _unflat(keys: string[], values: object = {}, cObj: object = {}): object {
-    let out: Record<string, unknown> = {};
+    const out: Record<string, unknown> = {};
     if (keys.length === 0) {
       return cObj;
     } else {
       if (Object.keys(cObj).length === 0) {
         cObj = values;
       }
-      let key: string | undefined = keys.pop();
+      const key: string | undefined = keys.pop();
       if (key) {
         out[key] = cObj;
       }
@@ -152,7 +152,7 @@ class Parser {
     delete this.context.currentGroup;
   }
   _split(str: string): string[] {
-    let out = [];
+    const out = [];
     out.push(...str.split("\n"));
     return out;
   }
@@ -233,8 +233,8 @@ class Parser {
       const reg = /([a-zA-Z0-9-_\.]*) (=)/gi;
       let result;
       while ((result = reg.exec(dataString))) {
-        let ogVal = result[0];
+        const ogVal = result[0];
-        let newVal = ogVal
+        const newVal = ogVal
           .replace(result[1], `"${result[1]}"`)
           .replace(result[2], ":");
         dataString = dataString.replace(ogVal, newVal);
@@ -332,9 +332,9 @@ class Parser {
         }
       }
       if (this._isDeclaration(line)) {
-        let kv = this._processDeclaration(line);
+        const kv = this._processDeclaration(line);
-        let key = kv.key;
+        const key = kv.key;
-        let value = kv.value;
+        const value = kv.value;
         if (!this.context.currentGroup) {
           this.context.output[key] = value;
         } else {
@@ -360,7 +360,7 @@ class Parser {
       let k = keys[i];
       if (k) {
         let v = obj[k];
-        let pathDeclaration = this._parseDeclarationName(k);
+        const pathDeclaration = this._parseDeclarationName(k);
         delete obj[k];
         if (pathDeclaration.length > 1) {
           const shift = pathDeclaration.shift();
@@ -400,7 +400,7 @@ function joinKeys(keys: string[]): string {
 }
 
 class Dumper {
-  maxPad: number = 0;
+  maxPad = 0;
   srcObject: object;
   output: string[] = [];
   constructor(srcObjc: object) {
@@ -507,11 +507,11 @@ class Dumper {
     }
   }
   _dateDeclaration(keys: string[], value: Date): string {
-    function dtPad(v: string, lPad: number = 2): string {
+    function dtPad(v: string, lPad = 2): string {
       return pad(v, lPad, { char: "0" });
     }
-    let m = dtPad((value.getUTCMonth() + 1).toString());
+    const m = dtPad((value.getUTCMonth() + 1).toString());
-    let d = dtPad(value.getUTCDate().toString());
+    const d = dtPad(value.getUTCDate().toString());
     const h = dtPad(value.getUTCHours().toString());
     const min = dtPad(value.getUTCMinutes().toString());
     const s = dtPad(value.getUTCSeconds().toString());

examples/cat.ts

@@ -1,7 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 async function cat(filenames: string[]): Promise<void> {
-  for (let filename of filenames) {
+  for (const filename of filenames) {
-    let file = await Deno.open(filename);
+    const file = await Deno.open(filename);
     await Deno.copy(Deno.stdout, file);
     file.close();
   }

examples/gist.ts

@@ -53,11 +53,11 @@ async function main(): Promise<void> {
   });
 
   if (res.ok) {
-    let resObj = await res.json();
+    const resObj = await res.json();
     console.log("Success");
     console.log(resObj["html_url"]);
   } else {
-    let err = await res.text();
+    const err = await res.text();
     console.error("Failure to POST", err);
   }
 }

flags/mod.ts

@@ -286,7 +286,7 @@ export function parse(
         argv._.push(flags.strings["_"] || !isNumber(arg) ? arg : Number(arg));
       }
       if (options.stopEarly) {
-        argv._.push.apply(argv._, args.slice(i + 1));
+        argv._.push(...args.slice(i + 1));
         break;
       }
     }

fmt/sprintf.ts

@@ -17,8 +17,8 @@ class Flags {
   space?: boolean;
   zero?: boolean;
   lessthan?: boolean;
-  width: number = -1;
+  width = -1;
-  precision: number = -1;
+  precision = -1;
 }
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
@@ -44,9 +44,9 @@ class Printf {
   i: number;
 
   state: State = State.PASSTHROUGH;
-  verb: string = "";
+  verb = "";
-  buf: string = "";
+  buf = "";
-  argNum: number = 0;
+  argNum = 0;
   flags: Flags = new Flags();
 
   haveSeen: boolean[];
@@ -64,7 +64,7 @@ class Printf {
 
   doPrintf(): string {
     for (; this.i < this.format.length; ++this.i) {
-      let c = this.format[this.i];
+      const c = this.format[this.i];
       switch (this.state) {
         case State.PASSTHROUGH:
           if (c === "%") {
@@ -104,9 +104,9 @@ class Printf {
   // %[<positional>]<flag>...<verb>
   handleFormat(): void {
     this.flags = new Flags();
-    let flags = this.flags;
+    const flags = this.flags;
     for (; this.i < this.format.length; ++this.i) {
-      let c = this.format[this.i];
+      const c = this.format[this.i];
       switch (this.state) {
         case State.PERCENT:
           switch (c) {
@@ -152,7 +152,7 @@ class Printf {
           break;
         case State.POSITIONAL: // either a verb or * only verb for now, TODO
           if (c === "*") {
-            let worp =
+            const worp =
               this.flags.precision === -1 ? WorP.WIDTH : WorP.PRECISION;
             this.handleWidthOrPrecisionRef(worp);
             this.state = State.PERCENT;
@@ -171,7 +171,7 @@ class Printf {
       // handle Positional should have already taken care of it...
       return;
     }
-    let arg = this.args[this.argNum];
+    const arg = this.args[this.argNum];
     this.haveSeen[this.argNum] = true;
     if (typeof arg === "number") {
       switch (wOrP) {
@@ -182,7 +182,7 @@ class Printf {
           this.flags.precision = arg;
       }
     } else {
-      let tmp = wOrP === WorP.WIDTH ? "WIDTH" : "PREC";
+      const tmp = wOrP === WorP.WIDTH ? "WIDTH" : "PREC";
       this.tmpError = `%!(BAD ${tmp} '${this.args[this.argNum]}')`;
     }
     this.argNum++;
@@ -271,7 +271,7 @@ class Printf {
     return;
   }
   handleLessThan(): string {
-    let arg = this.args[this.argNum];
+    const arg = this.args[this.argNum];
     if ((arg || {}).constructor.name !== "Array") {
       throw new Error(`arg ${arg} is not an array. Todo better error handling`);
     }
@@ -294,7 +294,7 @@ class Printf {
     } else if (this.args.length <= this.argNum) {
       this.buf += `%!(MISSING '${verb}')`;
     } else {
-      let arg = this.args[this.argNum]; // check out of range
+      const arg = this.args[this.argNum]; // check out of range
       this.haveSeen[this.argNum] = true; // keep track of used args
       if (this.flags.lessthan) {
         this.buf += this.handleLessThan();
@@ -404,7 +404,7 @@ class Printf {
     return nStr;
   }
 
-  fmtNumber(n: number, radix: number, upcase: boolean = false): string {
+  fmtNumber(n: number, radix: number, upcase = false): string {
     let num = Math.abs(n).toString(radix);
     const prec = this.flags.precision;
     if (prec !== -1) {
@@ -484,7 +484,7 @@ class Printf {
     return fractional;
   }
 
-  fmtFloatE(n: number, upcase: boolean = false): string {
+  fmtFloatE(n: number, upcase = false): string {
     const special = this.fmtFloatSpecial(n);
     if (special !== "") {
       return special;
@@ -553,7 +553,7 @@ class Printf {
     return this.padNum(`${dig}.${fractional}`, n < 0);
   }
 
-  fmtFloatG(n: number, upcase: boolean = false): string {
+  fmtFloatG(n: number, upcase = false): string {
     const special = this.fmtFloatSpecial(n);
     if (special !== "") {
       return special;
@@ -591,7 +591,7 @@ class Printf {
       throw Error("can't happen");
     }
 
-    let X = parseInt(m[F.exponent]) * (m[F.esign] === "-" ? -1 : 1);
+    const X = parseInt(m[F.exponent]) * (m[F.esign] === "-" ? -1 : 1);
     let nStr = "";
     if (P > X && X >= -4) {
       this.flags.precision = P - (X + 1);
@@ -616,14 +616,14 @@ class Printf {
     return this.pad(s);
   }
 
-  fmtHex(val: string | number, upper: boolean = false): string {
+  fmtHex(val: string | number, upper = false): string {
     // allow others types ?
     switch (typeof val) {
       case "number":
         return this.fmtNumber(val as number, 16, upper);
         break;
       case "string":
-        let sharp = this.flags.sharp && val.length !== 0;
+        const sharp = this.flags.sharp && val.length !== 0;
         let hex = sharp ? "0x" : "";
         const prec = this.flags.precision;
         const end = prec !== -1 ? min(prec, val.length) : val.length;
@@ -634,7 +634,7 @@ class Printf {
           // TODO: for now only taking into account the
           // lower half of the codePoint, ie. as if a string
           // is a list of 8bit values instead of UCS2 runes
-          let c = (val.charCodeAt(i) & 0xff).toString(16);
+          const c = (val.charCodeAt(i) & 0xff).toString(16);
           hex += c.length === 1 ? `0${c}` : c;
         }
         if (upper) {
@@ -652,7 +652,7 @@ class Printf {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   fmtV(val: any): string {
     if (this.flags.sharp) {
-      let options =
+      const options =
         this.flags.precision !== -1 ? { depth: this.flags.precision } : {};
       return this.pad(Deno.inspect(val, options));
     } else {
@@ -669,6 +669,6 @@ class Printf {
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 export function sprintf(format: string, ...args: any[]): string {
-  let printf = new Printf(format, ...args);
+  const printf = new Printf(format, ...args);
   return printf.doPrintf();
 }

fmt/sprintf_test.ts

@@ -3,7 +3,7 @@ import { sprintf } from "./sprintf.ts";
 import { assertEquals } from "../testing/asserts.ts";
 import { test, runIfMain } from "../testing/mod.ts";
 
-let S = sprintf;
+const S = sprintf;
 
 test(function noVerb(): void {
   assertEquals(sprintf("bla"), "bla");
@@ -589,8 +589,8 @@ const tests: Array<[string, any, string]> = [
 test(function testThorough(): void {
   tests.forEach((t, i): void => {
     //            p(t)
-    let is = S(t[0], t[1]);
+    const is = S(t[0], t[1]);
-    let should = t[2];
+    const should = t[2];
     assertEquals(
       is,
       should,
@@ -608,7 +608,7 @@ test(function testWeirdos(): void {
 });
 
 test(function formatV(): void {
-  let a = { a: { a: { a: { a: { a: { a: { a: {} } } } } } } };
+  const a = { a: { a: { a: { a: { a: { a: { a: {} } } } } } } };
   assertEquals(S("%v", a), "[object Object]");
   assertEquals(S("%#v", a), "{ a: { a: { a: { a: [Object] } } } }");
   assertEquals(
@@ -619,18 +619,18 @@ test(function formatV(): void {
 });
 
 test(function formatJ(): void {
-  let a = { a: { a: { a: { a: { a: { a: { a: {} } } } } } } };
+  const a = { a: { a: { a: { a: { a: { a: { a: {} } } } } } } };
   assertEquals(S("%j", a), `{"a":{"a":{"a":{"a":{"a":{"a":{"a":{}}}}}}}}`);
 });
 
 test(function flagLessThan(): void {
-  let a = { a: { a: { a: { a: { a: { a: { a: {} } } } } } } };
+  const a = { a: { a: { a: { a: { a: { a: { a: {} } } } } } } };
-  let aArray = [a, a, a];
+  const aArray = [a, a, a];
   assertEquals(
     S("%<#.1v", aArray),
     "[ { a: [Object] }, { a: [Object] }, { a: [Object] } ]"
   );
-  let fArray = [1.2345, 0.98765, 123456789.5678];
+  const fArray = [1.2345, 0.98765, 123456789.5678];
   assertEquals(S("%<.2f", fArray), "[ 1.23, 0.99, 123456789.57 ]");
 });
 

fs/copy.ts

@@ -21,11 +21,9 @@ async function ensureValidCopy(
   src: string,
   dest: string,
   options: CopyOptions,
-  isCopyFolder: boolean = false
+  isCopyFolder = false
 ): Promise<Deno.FileInfo> {
-  let destStat: Deno.FileInfo | null;
+  const destStat: Deno.FileInfo | null = await Deno.lstat(dest).catch(
-
-  destStat = await Deno.lstat(dest).catch(
     (): Promise<null> => Promise.resolve(null)
   );
 
@@ -47,7 +45,7 @@ function ensureValidCopySync(
   src: string,
   dest: string,
   options: CopyOptions,
-  isCopyFolder: boolean = false
+  isCopyFolder = false
 ): Deno.FileInfo {
   let destStat: Deno.FileInfo | null;
 

fs/glob.ts

@@ -112,7 +112,7 @@ export function joinGlobs(
   if (globs.length === 0) return ".";
   let joined: string | undefined;
   for (const glob of globs) {
-    let path = glob;
+    const path = glob;
     if (path.length > 0) {
       if (!joined) joined = path;
       else joined += `${SEP}${path}`;

fs/globrex.ts

@@ -127,7 +127,7 @@ export function globrex(
     if (c === ")") {
       if (ext.length) {
         add(c);
-        let type: string | undefined = ext.pop();
+        const type: string | undefined = ext.pop();
         if (type === "@") {
           add("{1}");
         } else if (type === "!") {
@@ -264,19 +264,19 @@ export function globrex(
       }
       // Move over all consecutive "*"'s.
       // Also store the previous and next characters
-      let prevChar = glob[i - 1];
+      const prevChar = glob[i - 1];
       let starCount = 1;
       while (glob[i + 1] === "*") {
         starCount++;
         i++;
       }
-      let nextChar = glob[i + 1];
+      const nextChar = glob[i + 1];
       if (!globstar) {
         // globstar is disabled, so treat any number of "*" as one
         add(".*");
       } else {
         // globstar is enabled, so determine if this is a globstar segment
-        let isGlobstar =
+        const isGlobstar =
           starCount > 1 && // multiple "*"'s
           // from the start of the segment
           [SEP_RAW, "/", undefined].includes(prevChar) &&

fs/globrex_test.ts

@@ -19,14 +19,14 @@ function match(
     opts = strWin;
     strWin = "";
   }
-  let res = globrex(glob, opts);
+  const res = globrex(glob, opts);
   return res.regex.test(isWin && strWin ? strWin : strUnix);
 }
 
 test({
   name: "globrex: standard",
   fn(): void {
-    let res = globrex("*.js");
+    const res = globrex("*.js");
     t.equal(typeof globrex, "function", "constructor is a typeof function");
     t.equal(res instanceof Object, true, "returns object");
     t.equal(res.regex.toString(), "/^.*\\.js$/", "returns regex object");

fs/path/parse_format_test.ts

@@ -1,5 +1,7 @@
 // Copyright the Browserify authors. MIT License.
 // Ported from https://github.com/browserify/path-browserify/
+/* eslint-disable @typescript-eslint/no-explicit-any */
+// TODO(kt3k): fix any types in this file
 
 import { test } from "../../testing/mod.ts";
 import { assertEquals } from "../../testing/asserts.ts";
@@ -80,7 +82,7 @@ const unixSpecialCaseFormatTests = [
 ];
 
 function checkParseFormat(path: any, paths: any): void {
-  paths.forEach(function(p: Record<string, unknown>[]) {
+  paths.forEach(function(p: Array<Record<string, unknown>>) {
     const element = p[0];
     const output = path.parse(element);
     assertEquals(typeof output.root, "string");
@@ -96,7 +98,7 @@ function checkParseFormat(path: any, paths: any): void {
 }
 
 function checkSpecialCaseParseFormat(path: any, testCases: any): void {
-  testCases.forEach(function(testCase: Record<string, unknown>[]) {
+  testCases.forEach(function(testCase: Array<Record<string, unknown>>) {
     const element = testCase[0];
     const expect = testCase[1];
     const output = path.parse(element);

fs/path/posix.ts

@@ -83,7 +83,7 @@ export function join(...paths: string[]): string {
   if (paths.length === 0) return ".";
   let joined: string | undefined;
   for (let i = 0, len = paths.length; i < len; ++i) {
-    let path = paths[i];
+    const path = paths[i];
     assertPath(path);
     if (path.length > 0) {
       if (!joined) joined = path;
@@ -107,11 +107,11 @@ export function relative(from: string, to: string): string {
 
   // Trim any leading backslashes
   let fromStart = 1;
-  let fromEnd = from.length;
+  const fromEnd = from.length;
   for (; fromStart < fromEnd; ++fromStart) {
     if (from.charCodeAt(fromStart) !== CHAR_FORWARD_SLASH) break;
   }
-  let fromLen = fromEnd - fromStart;
+  const fromLen = fromEnd - fromStart;
 
   // Trim any leading backslashes
   let toStart = 1;
@@ -119,10 +119,10 @@ export function relative(from: string, to: string): string {
   for (; toStart < toEnd; ++toStart) {
     if (to.charCodeAt(toStart) !== CHAR_FORWARD_SLASH) break;
   }
-  let toLen = toEnd - toStart;
+  const toLen = toEnd - toStart;
 
   // Compare paths to find the longest common path from root
-  let length = fromLen < toLen ? fromLen : toLen;
+  const length = fromLen < toLen ? fromLen : toLen;
   let lastCommonSep = -1;
   let i = 0;
   for (; i <= length; ++i) {
@@ -150,8 +150,8 @@ export function relative(from: string, to: string): string {
       }
       break;
     }
-    let fromCode = from.charCodeAt(fromStart + i);
+    const fromCode = from.charCodeAt(fromStart + i);
-    let toCode = to.charCodeAt(toStart + i);
+    const toCode = to.charCodeAt(toStart + i);
     if (fromCode !== toCode) break;
     else if (fromCode === CHAR_FORWARD_SLASH) lastCommonSep = i;
   }
@@ -328,6 +328,7 @@ export function extname(path: string): string {
 }
 
 export function format(pathObject: FormatInputPathObject): string {
+  /* eslint-disable max-len */
   if (pathObject === null || typeof pathObject !== "object") {
     throw new TypeError(
       `The "pathObject" argument must be of type Object. Received type ${typeof pathObject}`
@@ -339,9 +340,9 @@ export function format(pathObject: FormatInputPathObject): string {
 export function parse(path: string): ParsedPath {
   assertPath(path);
 
-  let ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
+  const ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
   if (path.length === 0) return ret;
-  let isAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
+  const isAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
   let start: number;
   if (isAbsolute) {
     ret.root = "/";

fs/path/win32.ts

@@ -304,7 +304,7 @@ export function join(...paths: string[]): string {
   let joined: string | undefined;
   let firstPart: string;
   for (let i = 0; i < pathsCount; ++i) {
-    let path = paths[i];
+    const path = paths[i];
     assertPath(path);
     if (path.length > 0) {
       if (joined === undefined) joined = firstPart = path;
@@ -369,8 +369,8 @@ export function relative(from: string, to: string): string {
 
   if (from === to) return "";
 
-  let fromOrig = resolve(from);
+  const fromOrig = resolve(from);
-  let toOrig = resolve(to);
+  const toOrig = resolve(to);
 
   if (fromOrig === toOrig) return "";
 
@@ -389,7 +389,7 @@ export function relative(from: string, to: string): string {
   for (; fromEnd - 1 > fromStart; --fromEnd) {
     if (from.charCodeAt(fromEnd - 1) !== CHAR_BACKWARD_SLASH) break;
   }
-  let fromLen = fromEnd - fromStart;
+  const fromLen = fromEnd - fromStart;
 
   // Trim any leading backslashes
   let toStart = 0;
@@ -401,10 +401,10 @@ export function relative(from: string, to: string): string {
   for (; toEnd - 1 > toStart; --toEnd) {
     if (to.charCodeAt(toEnd - 1) !== CHAR_BACKWARD_SLASH) break;
   }
-  let toLen = toEnd - toStart;
+  const toLen = toEnd - toStart;
 
   // Compare paths to find the longest common path from root
-  let length = fromLen < toLen ? fromLen : toLen;
+  const length = fromLen < toLen ? fromLen : toLen;
   let lastCommonSep = -1;
   let i = 0;
   for (; i <= length; ++i) {
@@ -433,8 +433,8 @@ export function relative(from: string, to: string): string {
       }
       break;
     }
-    let fromCode = from.charCodeAt(fromStart + i);
+    const fromCode = from.charCodeAt(fromStart + i);
-    let toCode = to.charCodeAt(toStart + i);
+    const toCode = to.charCodeAt(toStart + i);
     if (fromCode !== toCode) break;
     else if (fromCode === CHAR_BACKWARD_SLASH) lastCommonSep = i;
   }
@@ -737,6 +737,7 @@ export function extname(path: string): string {
 }
 
 export function format(pathObject: FormatInputPathObject): string {
+  /* eslint-disable max-len */
   if (pathObject === null || typeof pathObject !== "object") {
     throw new TypeError(
       `The "pathObject" argument must be of type Object. Received type ${typeof pathObject}`
@@ -748,7 +749,7 @@ export function format(pathObject: FormatInputPathObject): string {
 export function parse(path: string): ParsedPath {
   assertPath(path);
 
-  let ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
+  const ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
 
   const len = path.length;
   if (len === 0) return ret;

fs/path/zero_length_strings_test.ts

@@ -27,7 +27,8 @@ test(function normalizeZeroLength() {
 });
 
 test(function isAbsoluteZeroLength() {
-  // Since '' is not a valid path in any of the common environments, return false
+  // Since '' is not a valid path in any of the common environments,
+  // return false
   assertEquals(path.posix.isAbsolute(""), false);
   if (path.win32) assertEquals(path.win32.isAbsolute(""), false);
 });
@@ -40,7 +41,8 @@ test(function resolveZeroLength() {
 });
 
 test(function relativeZeroLength() {
-  // relative, internally calls resolve. So, '' is actually the current directory
+  // relative, internally calls resolve. So, '' is actually the current
+  // directory
   assertEquals(path.relative("", pwd), "");
   assertEquals(path.relative(pwd, ""), "");
   assertEquals(path.relative(pwd, pwd), "");

fs/walk.ts

@@ -22,7 +22,7 @@ function patternTest(patterns: RegExp[], path: string): boolean {
   // consistent results.
   // See: https://stackoverflow.com/a/1520853
   return patterns.some((pattern): boolean => {
-    let r = pattern.test(path);
+    const r = pattern.test(path);
     pattern.lastIndex = 0;
     return r;
   });
@@ -100,7 +100,7 @@ export async function* walk(
       options.onError(err);
     }
   }
-  for (let info of ls) {
+  for (const info of ls) {
     if (info.isSymlink()) {
       if (options.followSymlinks) {
         // TODO(ry) Re-enable followSymlinks.
@@ -154,7 +154,7 @@ export function* walkSync(
       options.onError(err);
     }
   }
-  for (let info of ls) {
+  for (const info of ls) {
     if (info.isSymlink()) {
       if (options.followSymlinks) {
         unimplemented();

http/cookie.ts

@@ -59,7 +59,7 @@ function toString(cookie: Cookie): string {
     out.push(`Path=${cookie.path}`);
   }
   if (cookie.expires) {
-    let dateString = toIMF(cookie.expires);
+    const dateString = toIMF(cookie.expires);
     out.push(`Expires=${dateString}`);
   }
   if (cookie.unparsed) {

http/cookie_test.ts

@@ -7,7 +7,7 @@ import { test } from "../testing/mod.ts";
 test({
   name: "[HTTP] Cookie parser",
   fn(): void {
-    let req = new ServerRequest();
+    const req = new ServerRequest();
     req.headers = new Headers();
     assertEquals(getCookies(req), {});
     req.headers = new Headers();
@@ -35,7 +35,7 @@ test({
 test({
   name: "[HTTP] Cookie Delete",
   fn(): void {
-    let res: Response = {};
+    const res: Response = {};
     delCookie(res, "deno");
     assertEquals(
       res.headers!.get("Set-Cookie"),
@@ -47,7 +47,7 @@ test({
 test({
   name: "[HTTP] Cookie Set",
   fn(): void {
-    let res: Response = {};
+    const res: Response = {};
 
     res.headers = new Headers();
     setCookie(res, { name: "Space", value: "Cat" });

http/file_server.ts

@@ -150,7 +150,7 @@ async function serveDir(
   const fileInfos = await readDir(dirPath);
   for (const fileInfo of fileInfos) {
     const filePath = posix.join(dirPath, fileInfo.name);
-    let fileUrl = posix.join(dirUrl, fileInfo.name);
+    const fileUrl = posix.join(dirUrl, fileInfo.name);
     if (fileInfo.name === "index.html" && fileInfo.isFile()) {
       // in case index.html as dir...
       return await serveFile(req, filePath);

http/racing_server_test.ts

@@ -21,7 +21,7 @@ function killServer(): void {
   server.stdout!.close();
 }
 
-let input = `GET / HTTP/1.1
+const input = `GET / HTTP/1.1
 
 GET / HTTP/1.1
 
@@ -31,7 +31,7 @@ GET / HTTP/1.1
 
 `;
 const HUGE_BODY_SIZE = 1024 * 1024;
-let output = `HTTP/1.1 200 OK
+const output = `HTTP/1.1 200 OK
 content-length: 8
 
 Hello 1

http/server.ts

@@ -139,7 +139,7 @@ export class ServerRequest {
           let line = await tp.readLine();
           if (line === Deno.EOF) throw new UnexpectedEOFError();
           // TODO: handle chunk extension
-          let [chunkSizeString] = line.split(";");
+          const [chunkSizeString] = line.split(";");
           let chunkSize = parseInt(chunkSizeString, 16);
           if (Number.isNaN(chunkSize) || chunkSize < 0) {
             throw new Error("Invalid chunk size");
@@ -157,7 +157,7 @@ export class ServerRequest {
           }
           const entityHeaders = await tp.readMIMEHeader();
           if (entityHeaders !== Deno.EOF) {
-            for (let [k, v] of entityHeaders) {
+            for (const [k, v] of entityHeaders) {
               this.headers.set(k, v);
             }
           }
@@ -242,8 +242,6 @@ export function parseHTTPVersion(vers: string): [number, number] {
     default: {
       const Big = 1000000; // arbitrary upper bound
       const digitReg = /^\d+$/; // test if string is only digit
-      let major: number;
-      let minor: number;
 
       if (!vers.startsWith("HTTP/")) {
         break;
@@ -254,8 +252,8 @@ export function parseHTTPVersion(vers: string): [number, number] {
         break;
       }
 
-      let majorStr = vers.substring(vers.indexOf("/") + 1, dot);
+      const majorStr = vers.substring(vers.indexOf("/") + 1, dot);
-      major = parseInt(majorStr);
+      const major = parseInt(majorStr);
       if (
         !digitReg.test(majorStr) ||
         isNaN(major) ||
@@ -265,8 +263,8 @@ export function parseHTTPVersion(vers: string): [number, number] {
         break;
       }
 
-      let minorStr = vers.substring(dot + 1);
+      const minorStr = vers.substring(dot + 1);
-      minor = parseInt(minorStr);
+      const minor = parseInt(minorStr);
       if (
         !digitReg.test(minorStr) ||
         isNaN(minor) ||

http/server_test.ts

@@ -349,7 +349,7 @@ const mockConn = {
 };
 
 test(async function readRequestError(): Promise<void> {
-  let input = `GET / HTTP/1.1
+  const input = `GET / HTTP/1.1
 malformedHeader
 `;
   const reader = new BufReader(new StringReader(input));

http/testdata/simple_server.ts

@@ -5,7 +5,7 @@ import { serve } from "../server.ts";
 window.onload = async function main() {
   const addr = "0.0.0.0:4502";
   console.log(`Simple server listening on ${addr}`);
-  for await (let req of serve(addr)) {
+  for await (const req of serve(addr)) {
     req.respond({});
   }
 }

installer/mod.ts

@@ -79,7 +79,7 @@ function getFlagFromPermission(perm: Permission): string {
 function getInstallerDir(): string {
   // In Windows's Powershell $HOME environmental variable maybe null
   // if so use $HOMEPATH instead.
-  let { HOME, HOMEPATH } = env();
+  const { HOME, HOMEPATH } = env();
 
   const HOME_PATH = HOME || HOMEPATH;
 
@@ -109,7 +109,7 @@ function checkIfExistsInPath(filePath: string): boolean {
   // $HOMEDRIVE is only used on Windows.
   const { PATH, Path, HOMEDRIVE } = env();
 
-  let envPath = (PATH as string) || (Path as string) || "";
+  const envPath = (PATH as string) || (Path as string) || "";
 
   const paths = envPath.split(isWindows ? ";" : ":");
 

io/bufio.ts

@@ -407,7 +407,7 @@ export class BufReader implements Reader {
  */
 export class BufWriter implements Writer {
   buf: Uint8Array;
-  n: number = 0;
+  n = 0;
   err: Error | null = null;
 
   /** return new BufWriter unless w is BufWriter */

io/bufio_test.ts

@@ -32,7 +32,7 @@ async function readBytes(buf: BufReader): Promise<string> {
   const b = new Uint8Array(1000);
   let nb = 0;
   while (true) {
-    let c = await buf.readByte();
+    const c = await buf.readByte();
     if (c === Deno.EOF) {
       break; // EOF
     }
@@ -122,10 +122,10 @@ test(async function bufioBufReader(): Promise<void> {
   }
   texts[texts.length - 1] = all;
 
-  for (let text of texts) {
+  for (const text of texts) {
-    for (let readmaker of readMakers) {
+    for (const readmaker of readMakers) {
-      for (let bufreader of bufreaders) {
+      for (const bufreader of bufreaders) {
-        for (let bufsize of bufsizes) {
+        for (const bufsize of bufsizes) {
           const read = readmaker.fn(stringsReader(text));
           const buf = new BufReader(read, bufsize);
           const s = await bufreader.fn(buf);
@@ -210,8 +210,8 @@ class TestReader implements Reader {
 async function testReadLine(input: Uint8Array): Promise<void> {
   for (let stride = 1; stride < 2; stride++) {
     let done = 0;
-    let reader = new TestReader(input, stride);
+    const reader = new TestReader(input, stride);
-    let l = new BufReader(reader, input.byteLength + 1);
+    const l = new BufReader(reader, input.byteLength + 1);
     while (true) {
       const r = await l.readLine();
       if (r === Deno.EOF) {
@@ -220,7 +220,7 @@ async function testReadLine(input: Uint8Array): Promise<void> {
       const { line, more } = r;
       assertEquals(more, false);
       // eslint-disable-next-line @typescript-eslint/restrict-plus-operands
-      let want = testOutput.subarray(done, done + line.byteLength);
+      const want = testOutput.subarray(done, done + line.byteLength);
       assertEquals(
         line,
         want,
@@ -244,9 +244,9 @@ test(async function bufioReadLine(): Promise<void> {
 
 test(async function bufioPeek(): Promise<void> {
   const decoder = new TextDecoder();
-  let p = new Uint8Array(10);
+  const p = new Uint8Array(10);
   // string is 16 (minReadBufferSize) long.
-  let buf = new BufReader(
+  const buf = new BufReader(
     stringsReader("abcdefghijklmnop"),
     MIN_READ_BUFFER_SIZE
   );
@@ -281,7 +281,7 @@ test(async function bufioPeek(): Promise<void> {
   actual = assertNotEOF(await buf.peek(2));
   assertEquals(decoder.decode(actual), "de");
 
-  let res = await buf.read(p.subarray(0, 3));
+  const res = await buf.read(p.subarray(0, 3));
   assertEquals(decoder.decode(p.subarray(0, 3)), "def");
   assert(res !== Deno.EOF);
 
@@ -327,8 +327,8 @@ test(async function bufioWriter(): Promise<void> {
   }
 
   const w = new Buffer();
-  for (let nwrite of bufsizes) {
+  for (const nwrite of bufsizes) {
-    for (let bs of bufsizes) {
+    for (const bs of bufsizes) {
       // Write nwrite bytes using buffer size bs.
       // Check that the right amount makes it out
       // and that the data is correct.

io/readers_test.ts

@@ -17,13 +17,13 @@ test(async function ioStringReader(): Promise<void> {
 test(async function ioStringReader(): Promise<void> {
   const r = new StringReader("abcdef");
   const buf = new Uint8Array(3);
-  let res1 = await r.read(buf);
+  const res1 = await r.read(buf);
   assertEquals(res1, 3);
   assertEquals(decode(buf), "abc");
-  let res2 = await r.read(buf);
+  const res2 = await r.read(buf);
   assertEquals(res2, 3);
   assertEquals(decode(buf), "def");
-  let res3 = await r.read(buf);
+  const res3 = await r.read(buf);
   assertEquals(res3, Deno.EOF);
   assertEquals(decode(buf), "def");
 });

io/util_test.ts

@@ -6,7 +6,7 @@ import { copyBytes, tempFile } from "./util.ts";
 import * as path from "../fs/path.ts";
 
 test(function testCopyBytes(): void {
-  let dst = new Uint8Array(4);
+  const dst = new Uint8Array(4);
 
   dst.fill(0);
   let src = Uint8Array.of(1, 2);

io/writers.ts

@@ -5,7 +5,7 @@ import { decode, encode } from "../strings/mod.ts";
 /** Writer utility for buffering string chunks */
 export class StringWriter implements Writer {
   private chunks: Uint8Array[] = [];
-  private byteLength: number = 0;
+  private byteLength = 0;
   private cache: string | undefined;
 
   constructor(private base: string = "") {

log/logger_test.ts

@@ -50,7 +50,7 @@ test(function customHandler(): void {
 test(function logFunctions(): void {
   const doLog = (level: string): TestHandler => {
     const handler = new TestHandler(level);
-    let logger = new Logger(level, [handler]);
+    const logger = new Logger(level, [handler]);
     logger.debug("foo");
     logger.info("bar");
     logger.warning("baz");

mime/multipart.ts

@@ -130,7 +130,7 @@ export function scanUntilBoundary(
 
 class PartReader implements Reader, Closer {
   n: number | Deno.EOF = 0;
-  total: number = 0;
+  total = 0;
 
   constructor(private mr: MultipartReader, public readonly headers: Headers) {}
 
@@ -312,7 +312,7 @@ export class MultipartReader {
   }
 
   private currentPart: PartReader | undefined;
-  private partsRead: number = 0;
+  private partsRead = 0;
 
   private async nextPart(): Promise<PartReader | Deno.EOF> {
     if (this.currentPart) {
@@ -359,7 +359,7 @@ export class MultipartReader {
     if (!hasPrefix(line, this.dashBoundaryDash)) {
       return false;
     }
-    let rest = line.slice(this.dashBoundaryDash.length, line.length);
+    const rest = line.slice(this.dashBoundaryDash.length, line.length);
     return rest.length === 0 || equal(skipLWSPChar(rest), this.newLine);
   }
 
@@ -375,7 +375,7 @@ export class MultipartReader {
 class PartWriter implements Writer {
   closed = false;
   private readonly partHeader: string;
-  private headersWritten: boolean = false;
+  private headersWritten = false;
 
   constructor(
     private writer: Writer,
@@ -436,7 +436,7 @@ export class MultipartWriter {
 
   private lastPart: PartWriter | undefined;
   private bufWriter: BufWriter;
-  private isClosed: boolean = false;
+  private isClosed = false;
 
   constructor(private readonly writer: Writer, boundary?: string) {
     if (boundary !== void 0) {

prettier/main_test.ts

@@ -54,21 +54,21 @@ test(async function testPrettierCheckAndFormatFiles(): Promise<void> {
     join(tempDir, "2.ts")
   ];
 
-  var { code, stdout } = await run([...cmd, "--check", ...files]);
+  let p = await run([...cmd, "--check", ...files]);
-  assertEquals(code, 1);
+  assertEquals(p.code, 1);
-  assertEquals(normalizeOutput(stdout), "Some files are not formatted");
+  assertEquals(normalizeOutput(p.stdout), "Some files are not formatted");
 
-  var { code, stdout } = await run([...cmd, "--write", ...files]);
+  p = await run([...cmd, "--write", ...files]);
-  assertEquals(code, 0);
+  assertEquals(p.code, 0);
   assertEquals(
-    normalizeOutput(stdout),
+    normalizeOutput(p.stdout),
     normalizeOutput(`Formatting ${tempDir}/0.ts
 Formatting ${tempDir}/1.js`)
   );
 
-  var { code, stdout } = await run([...cmd, "--check", ...files]);
+  p = await run([...cmd, "--check", ...files]);
-  assertEquals(code, 0);
+  assertEquals(p.code, 0);
-  assertEquals(normalizeOutput(stdout), "Every file is formatted");
+  assertEquals(normalizeOutput(p.stdout), "Every file is formatted");
 
   emptyDir(tempDir);
 });
@@ -79,23 +79,23 @@ test(async function testPrettierCheckAndFormatDirs(): Promise<void> {
 
   const dirs = [join(tempDir, "foo"), join(tempDir, "bar")];
 
-  var { code, stdout } = await run([...cmd, "--check", ...dirs]);
+  let p = await run([...cmd, "--check", ...dirs]);
-  assertEquals(code, 1);
+  assertEquals(p.code, 1);
-  assertEquals(normalizeOutput(stdout), "Some files are not formatted");
+  assertEquals(normalizeOutput(p.stdout), "Some files are not formatted");
 
-  var { code, stdout } = await run([...cmd, "--write", ...dirs]);
+  p = await run([...cmd, "--write", ...dirs]);
-  assertEquals(code, 0);
+  assertEquals(p.code, 0);
   assertEquals(
-    normalizeOutput(stdout),
+    normalizeOutput(p.stdout),
     normalizeOutput(`Formatting ${tempDir}/bar/0.ts
 Formatting ${tempDir}/bar/1.js
 Formatting ${tempDir}/foo/0.ts
 Formatting ${tempDir}/foo/1.js`)
   );
 
-  var { code, stdout } = await run([...cmd, "--check", ...dirs]);
+  p = await run([...cmd, "--check", ...dirs]);
-  assertEquals(code, 0);
+  assertEquals(p.code, 0);
-  assertEquals(normalizeOutput(stdout), "Every file is formatted");
+  assertEquals(normalizeOutput(p.stdout), "Every file is formatted");
 
   emptyDir(tempDir);
 });

strings/pad.ts

@@ -60,7 +60,7 @@ export function pad(
       out = out.padEnd(strLen, opts.char);
     }
   } else if (opts.strict && outL > strLen) {
-    let addChar = opts.strictChar ? opts.strictChar : "";
+    const addChar = opts.strictChar ? opts.strictChar : "";
     if (opts.strictSide === "left") {
       let toDrop = outL - strLen;
       if (opts.strictChar) {

testing/asserts.ts

@@ -235,7 +235,7 @@ export function assertArrayContains(
   expected: unknown[],
   msg?: string
 ): void {
-  let missing: unknown[] = [];
+  const missing: unknown[] = [];
   for (let i = 0; i < expected.length; i++) {
     let found = false;
     for (let j = 0; j < actual.length; j++) {

testing/bench_test.ts

@@ -19,7 +19,7 @@ test(async function benching(): Promise<void> {
   bench(async function forAwaitFetchDenolandX10(b): Promise<void> {
     b.start();
     for (let i = 0; i < 10; i++) {
-      let r = await fetch("https://deno.land/");
+      const r = await fetch("https://deno.land/");
       await r.text();
     }
     b.stop();
@@ -31,7 +31,7 @@ test(async function benching(): Promise<void> {
     await Promise.all(
       urls.map(
         async (denoland: string): Promise<void> => {
-          let r = await fetch(denoland);
+          const r = await fetch(denoland);
           await r.text();
         }
       )

testing/format.ts

@@ -271,7 +271,7 @@ function printIteratorEntries(
   // Too bad, so sad that separator for ECMAScript Map has been ' => '
   // What a distracting diff if you change a data structure to/from
   // ECMAScript Object or Immutable.Map/OrderedMap which use the default.
-  separator: string = ": "
+  separator = ": "
 ): string {
   let result = "";
   let current = iterator.next();

testing/format_test.ts

@@ -13,6 +13,7 @@ import { format } from "./format.ts";
 // eslint-disable-next-line max-len
 // eslint-disable-next-line @typescript-eslint/no-unused-vars,@typescript-eslint/no-explicit-any
 function returnArguments(...args: any[]): IArguments {
+  // eslint-disable-next-line prefer-rest-params
   return arguments;
 }
 

testing/mod.ts

@@ -62,7 +62,7 @@ function disableConsole(): void {
 }
 
 const encoder = new TextEncoder();
-function print(txt: string, newline: boolean = true): void {
+function print(txt: string, newline = true): void {
   if (newline) {
     txt += "\n";
   }
@@ -172,11 +172,11 @@ function createTestResults(tests: TestDefinition[]): TestResults {
   );
 }
 
-function formatTestTime(time: number = 0): string {
+function formatTestTime(time = 0): string {
   return `${time.toFixed(2)}ms`;
 }
 
-function promptTestTime(time: number = 0, displayWarning = false): string {
+function promptTestTime(time = 0, displayWarning = false): string {
   // if time > 5s we display a warning
   // only for test time, not the full runtime
   if (displayWarning && time >= 5000) {
@@ -308,10 +308,9 @@ async function runTestsSerial(
       print(`${yellow("RUNNING")} ${name}`, false);
     }
     try {
-      let start, end;
+      const start = performance.now();
-      start = performance.now();
       await fn();
-      end = performance.now();
+      const end = performance.now();
       if (disableLog) {
         // Rewriting the current prompt line to erase `running ....`
         print(CLEAR_LINE, false);

textproto/mod.ts

@@ -66,7 +66,7 @@ export class TextProtoReader {
    *	}
    */
   async readMIMEHeader(): Promise<Headers | Deno.EOF> {
-    let m = new Headers();
+    const m = new Headers();
     let line: Uint8Array;
 
     // The first line cannot start with a leading space.
@@ -87,7 +87,7 @@ export class TextProtoReader {
     }
 
     while (true) {
-      let kv = await this.readLineSlice(); // readContinuedLineSlice
+      const kv = await this.readLineSlice(); // readContinuedLineSlice
       if (kv === Deno.EOF) throw new UnexpectedEOFError();
       if (kv.byteLength === 0) return m;
 
@@ -104,7 +104,7 @@ export class TextProtoReader {
       }
 
       //let key = canonicalMIMEHeaderKey(kv.subarray(0, endKey));
-      let key = str(kv.subarray(0, endKey));
+      const key = str(kv.subarray(0, endKey));
 
       // As per RFC 7230 field-name is a token,
       // tokens consist of one or more chars.
@@ -123,7 +123,7 @@ export class TextProtoReader {
       ) {
         i++;
       }
-      let value = str(kv.subarray(i));
+      const value = str(kv.subarray(i));
 
       // In case of invalid header we swallow the error
       // example: "Audio Mode" => invalid due to space in the key

tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "tsconfig.test.json",
+  "extends": "./tsconfig.test.json",
   "compilerOptions": {
     "allowJs": true,
     "baseUrl": ".",

util/async.ts

@@ -100,7 +100,7 @@ export async function collectUint8Arrays(
   }
   const collected = new Uint8Array(length);
   let offset = 0;
-  for (let chunk of chunks) {
+  for (const chunk of chunks) {
     collected.set(chunk, offset);
     offset += chunk.length;
   }

ws/mod.ts

@@ -368,7 +368,7 @@ export function createSecAccept(nonce: string): string {
   const sha1 = new Sha1();
   sha1.update(nonce + kGUID);
   const bytes = sha1.digest();
-  return btoa(String.fromCharCode.apply(String, bytes));
+  return btoa(String.fromCharCode(...bytes));
 }
 
 /** Upgrade given TCP connection into websocket connection */
@@ -480,7 +480,7 @@ export async function connectWebSocket(
   headers: Headers = new Headers()
 ): Promise<WebSocket> {
   const url = new URL(endpoint);
-  let { hostname } = url;
+  const { hostname } = url;
   let conn: Conn;
   if (url.protocol === "http:" || url.protocol === "ws:") {
     const port = parseInt(url.port || "80");

xeval/mod.ts

@@ -70,7 +70,7 @@ async function* chunks(
   let inspectIndex = 0;
   let matchIndex = 0;
   while (true) {
-    let result = await reader.read(inspectArr);
+    const result = await reader.read(inspectArr);
     if (result === EOF) {
       // Yield last chunk.
       const lastChunk = inputBuffer.toString();
@@ -81,7 +81,7 @@ async function* chunks(
       // Discard all remaining and silently fail.
       return;
     }
-    let sliceRead = inspectArr.subarray(0, result as number);
+    const sliceRead = inspectArr.subarray(0, result as number);
     await writeAll(inputBuffer, sliceRead);
 
     let sliceToProcess = inputBuffer.bytes();