add some eslint-typescript rules

Author: gfx

.eslintrc.js

@@ -42,18 +42,23 @@ module.exports = {
     ],
     "@typescript-eslint/restrict-plus-operands": ["warn", { "checkCompoundAssignments": true }],
     "@typescript-eslint/no-throw-literal": "warn",
+    "@typescript-eslint/unbound-method": "warn",
+    "@typescript-eslint/explicit-module-boundary-types": "warn",
     "@typescript-eslint/no-extra-semi": "warn",
     "@typescript-eslint/no-extra-non-null-assertion": "warn",
     "@typescript-eslint/no-unused-vars": ["warn", { "argsIgnorePattern": "^_" }],
     "@typescript-eslint/no-use-before-define": "warn",
     "@typescript-eslint/no-for-in-array": "warn",
+    "@typescript-eslint/no-unsafe-argument": "warn",
+    "@typescript-eslint/no-unsafe-call": "warn",
+    // "@typescript-eslint/no-unsafe-member-access": "warn", // too strict, especially for testing
     "@typescript-eslint/no-unnecessary-condition": ["warn", { "allowConstantLoopConditions": true }],
+    "@typescript-eslint/no-unnecessary-type-constraint": "warn",
     "@typescript-eslint/no-implied-eval": "warn",
     "@typescript-eslint/no-non-null-asserted-optional-chain": "warn",
     "@typescript-eslint/no-invalid-void-type": "warn",
     "@typescript-eslint/no-loss-of-precision": "warn",
     "@typescript-eslint/no-confusing-void-expression": "warn",
-    "@typescript-eslint/no-unnecessary-type-constraint": "warn",
     "@typescript-eslint/prefer-for-of": "warn",
     "@typescript-eslint/prefer-includes": "warn",
     "@typescript-eslint/prefer-string-starts-ends-with": "warn",
@@ -62,9 +67,9 @@ module.exports = {
     "@typescript-eslint/prefer-nullish-coalescing": "warn",
     "@typescript-eslint/prefer-optional-chain": "warn",
     "@typescript-eslint/prefer-ts-expect-error": "warn",
+    "@typescript-eslint/prefer-regexp-exec": "warn",
 
     "@typescript-eslint/indent": "off",
-    "@typescript-eslint/explicit-module-boundary-types": "off",
     "@typescript-eslint/no-explicit-any": "off",
     "@typescript-eslint/no-empty-interface": "off",
     "@typescript-eslint/no-empty-function": "off",

src/CachedKeyDecoder.ts

@@ -26,7 +26,7 @@ export class CachedKeyDecoder implements KeyDecoder {
     }
   }
 
-  public canBeCached(byteLength: number) {
+  public canBeCached(byteLength: number): boolean {
     return byteLength > 0 && byteLength <= this.maxKeyLength;
   }
 

src/Decoder.ts

@@ -48,7 +48,7 @@ export const DataViewIndexOutOfBoundsError: typeof Error = (() => {
     // IE11: The spec says it should throw RangeError,
     // IE11: but in IE11 it throws TypeError.
     EMPTY_VIEW.getInt8(0);
-  } catch (e) {
+  } catch (e: any) {
     return e.constructor;
   }
   throw new Error("never reached");
@@ -65,7 +65,7 @@ export class DecodeError extends Error {
     super(message);
 
     // fix the prototype chain in a cross-platform way
-    const proto = Object.create(DecodeError.prototype);
+    const proto: typeof DecodeError.prototype = Object.create(DecodeError.prototype);
     Object.setPrototypeOf(this, proto);
 
     Object.defineProperty(this, "name", {
@@ -188,11 +188,11 @@ export class Decoder<ContextType = undefined> {
     );
   }
 
-  public decodeArrayStream(stream: AsyncIterable<ArrayLike<number> | BufferSource>) {
+  public decodeArrayStream(stream: AsyncIterable<ArrayLike<number> | BufferSource>): AsyncGenerator<unknown, void, unknown> {
     return this.decodeMultiAsync(stream, true);
   }
 
-  public decodeStream(stream: AsyncIterable<ArrayLike<number> | BufferSource>) {
+  public decodeStream(stream: AsyncIterable<ArrayLike<number> | BufferSource>): AsyncGenerator<unknown, void, unknown> {
     return this.decodeMultiAsync(stream, false);
   }
 

src/decodeAsync.ts

@@ -26,7 +26,7 @@ export async function decodeAsync<ContextType>(
 export function decodeArrayStream<ContextType>(
   streamLike: ReadableStreamLike<ArrayLike<number> | BufferSource>,
   options: DecodeOptions<SplitUndefined<ContextType>> = defaultDecodeOptions as any,
-) {
+): AsyncGenerator<unknown, void, unknown> {
   const stream = ensureAsyncIterable(streamLike);
 
   const decoder = new Decoder(
@@ -45,7 +45,7 @@ export function decodeArrayStream<ContextType>(
 export function decodeMultiStream<ContextType>(
   streamLike: ReadableStreamLike<ArrayLike<number> | BufferSource>,
   options: DecodeOptions<SplitUndefined<ContextType>> = defaultDecodeOptions as any,
-) {
+): AsyncGenerator<unknown, void, unknown> {
   const stream = ensureAsyncIterable(streamLike);
 
   const decoder = new Decoder(
@@ -67,6 +67,6 @@ export function decodeMultiStream<ContextType>(
 export function decodeStream<ContextType>(
   streamLike: ReadableStreamLike<ArrayLike<number> | BufferSource>,
   options: DecodeOptions<SplitUndefined<ContextType>> = defaultDecodeOptions as any,
-) {
+): AsyncGenerator<unknown, void, unknown> {
   return decodeMultiStream(streamLike, options);
 }

src/utils/int.ts

@@ -15,13 +15,13 @@ export function setInt64(view: DataView, offset: number, value: number): void {
   view.setUint32(offset + 4, low);
 }
 
-export function getInt64(view: DataView, offset: number) {
+export function getInt64(view: DataView, offset: number): number {
   const high = view.getInt32(offset);
   const low = view.getUint32(offset + 4);
   return high * 0x1_0000_0000 + low;
 }
 
-export function getUint64(view: DataView, offset: number) {
+export function getUint64(view: DataView, offset: number): number {
   const high = view.getUint32(offset);
   const low = view.getUint32(offset + 4);
   return high * 0x1_0000_0000 + low;

src/utils/typedArrays.ts

@@ -1,4 +1,4 @@
-export function ensureUint8Array(buffer: ArrayLike<number> | Uint8Array | ArrayBufferView | ArrayBuffer) {
+export function ensureUint8Array(buffer: ArrayLike<number> | Uint8Array | ArrayBufferView | ArrayBuffer): Uint8Array {
   if (buffer instanceof Uint8Array) {
     return buffer;
   } else if (ArrayBuffer.isView(buffer)) {

test/codec-float.test.ts

@@ -1,7 +1,10 @@
 import assert from "assert";
 import { decode } from "../src";
+// ieee754 module's type declarations are too strict
+// https://github.com/feross/ieee754/pull/38
+// @ts-nocheck
+import * as ieee754 from "ieee754";
 
-const ieee754 = require("ieee754");
 
 const FLOAT32_TYPE = 0xca;
 const FLOAT64_TYPE = 0xcb;

test/decode-blob.test.ts

@@ -2,11 +2,12 @@ import assert from "assert";
 import "web-streams-polyfill";
 import { encode, decode, decodeAsync } from "@msgpack/msgpack";
 
-const MyBlob = typeof Blob !== "undefined" ? Blob : require("blob-polyfill").Blob;
+const MyBlob: typeof Blob = typeof Blob !== "undefined" ? Blob : require("blob-polyfill").Blob;
 
 describe("Blob", () => {
   it("decodes it with `decode()`", async function () {
     const blob = new MyBlob([encode("Hello!")]);
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
     if (!blob.arrayBuffer) {
       this.skip();
     }
@@ -15,6 +16,7 @@ describe("Blob", () => {
 
   it("decodes it with `decodeAsync()`", async function () {
     const blob = new MyBlob([encode("Hello!")]);
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
     if (!blob.stream) {
       this.skip();
     }

test/edge-cases.test.ts

@@ -1,7 +1,7 @@
 // kind of hand-written fuzzing data
 // any errors should not break Encoder/Decoder instance states
 import assert from "assert";
-import { encode, decode, decodeAsync, Encoder, Decoder } from "../src";
+import { encode, decode, Encoder, Decoder } from "../src";
 import { DataViewIndexOutOfBoundsError } from "../src/Decoder";
 
 function testEncoder(encoder: Encoder): void {

test/karma-run.ts

@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-unsafe-call */
 // the util module requires process.env
 (globalThis as any).process = {
   env: {},