Linter: update to eslint v9, and enable TS recommended rules

This eslint version brings breaking changes related to the eslint config.

Author: larabr

.eslintrc.cjs

@@ -0,0 +1,89 @@
+// @ts-check
+import eslint from '@eslint/js';
+import { defineConfig } from 'eslint/config';
+import tseslint from 'typescript-eslint';
+import globals from 'globals';
+// @ts-expect-error missing declarations
+import pluginChaiFriendly from 'eslint-plugin-chai-friendly';
+import pluginImport from 'eslint-plugin-import';
+import pluginStylistic from '@stylistic/eslint-plugin';
+
+export default defineConfig(
+  eslint.configs.recommended,
+  tseslint.configs.recommended,
+  {
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'module',
+      parserOptions: {
+        projectService: true,
+        tsconfigRootDir: import.meta.dirname
+      },
+      globals: {
+        ...globals.browser,
+        ...globals.mocha
+      }
+    },
+    settings: {
+      'import/resolver': {
+        typescript: { alwaysTryTypes: true }
+      }
+    },
+    plugins: {
+      'chai-friendly': pluginChaiFriendly,
+      'import': pluginImport,
+      '@stylistic': pluginStylistic
+    },
+    rules: {
+      'no-unused-vars': 'off',
+      '@typescript-eslint/no-unused-vars': ['error', { 'argsIgnorePattern': '^_', 'varsIgnorePattern': '^_' }],
+      'no-redeclare': 'off',
+      '@typescript-eslint/no-redeclare': 'error',
+      'prefer-spread': 'off',
+      'no-restricted-syntax': 'off',
+      'consistent-return': 'off',
+      'object-curly-newline': 'off',
+      'prefer-template': 'off',
+      'no-plusplus': 'off',
+      'no-continue': 'off',
+      'no-bitwise': 'off',
+      'no-await-in-loop': 'off',
+      'no-sequences': 'warn',
+      'no-param-reassign': 'warn',
+      'no-return-assign': 'warn',
+      'no-else-return': ['error', { 'allowElseIf': true }],
+      'no-shadow': 'off',
+      'no-undef': 'error',
+      'no-constant-condition': ['error', { 'checkLoops': 'all' }],
+      'no-unused-expressions': 'off',
+      '@typescript-eslint/no-unused-expressions': 'off',
+      'chai-friendly/no-unused-expressions': [ 'error', { allowShortCircuit: true } ],
+      'arrow-body-style': 'off',
+      'space-before-function-paren': 'off',
+      'operator-linebreak': 'off',
+      'implicit-arrow-linebreak': 'off',
+      'no-underscore-dangle': 'off',
+      'import/prefer-default-export': 'off',
+      'import/no-extraneous-dependencies': 'off',
+      'import/no-unassigned-import': 'error',
+      'import/named': 'error',
+      'max-len': ['error', {
+        'ignoreComments': true,
+        'code': 130,
+        'ignoreStrings': true,
+        'ignoreTemplateLiterals': true,
+        'ignoreRegExpLiterals': true
+      }],
+      'no-multiple-empty-lines': ['error'],
+      'no-trailing-spaces': ['error'],
+      'eol-last': ['error'],
+      'padded-blocks': 'off',
+      'max-classes-per-file': 'off',
+      'no-empty': 'off',
+      '@stylistic/semi': 'error',
+      '@stylistic/indent': ['error', 2],
+      '@stylistic/quotes': ['error', 'single', { 'avoidEscape': true }],
+      '@typescript-eslint/no-explicit-any': 'off'
+    }
+  }
+);

eslint.config.js

@@ -51,7 +51,7 @@ function Reader(input) {
     if (doneReading) {
       try {
         doneReadingSet.add(input);
-      } catch(e) {}
+      } catch {}
     }
   };
 }

lib/reader.js

@@ -66,14 +66,14 @@ function concat(list) {
  * @returns {ReadableStream} Concatenated list
  */
 function concatStream(list) {
-  list = list.map(toStream);
+  const streamedList = list.map(toStream);
   const transform = transformWithCancel(async function(reason) {
     await Promise.all(transforms.map(stream => cancel(stream, reason)));
   });
   let prev = Promise.resolve();
-  const transforms = list.map((stream, i) => transformPair(stream, (readable, writable) => {
+  const transforms = streamedList.map((stream, i) => transformPair(stream, (readable, _writable) => {
     prev = prev.then(() => pipe(readable, transform.writable, {
-      preventClose: i !== list.length - 1
+      preventClose: i !== streamedList.length - 1
     }));
     return prev;
   }));
@@ -126,7 +126,7 @@ async function pipe(input, target, {
         preventAbort,
         preventCancel
       });
-    } catch(e) {}
+    } catch {}
     return;
   }
   if (!isStream(input)) {
@@ -452,11 +452,11 @@ function passiveClone(input) {
               await writer.ready;
               const { done, value } = await reader.read();
               if (done) {
-                try { controller.close(); } catch(e) {}
+                try { controller.close(); } catch {}
                 await writer.close();
                 return;
               }
-              try { controller.enqueue(value); } catch(e) {}
+              try { controller.enqueue(value); } catch {}
               await writer.write(value);
             }
           } catch(e) {
@@ -561,7 +561,7 @@ function slice(input, begin=0, end=Infinity) {
           lastBytes = slice(returnValue, end);
           return slice(returnValue, begin, end);
         }
-          lastBytes = returnValue;
+        lastBytes = returnValue;
       });
     }
     console.warn(`stream.slice(input, ${begin}, ${end}) not implemented efficiently.`);