Upgrade ESLint, rework config, split out Prettier (#141)

.github/workflows/test.yml

@@ -40,4 +40,4 @@ jobs:
 
       - run: npm install-ci-test
 
-      - run: npm run eslint
+      - run: npm run lint

eslint.config.mjs

@@ -0,0 +1,72 @@
+import path from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+import { fixupConfigRules, fixupPluginRules } from '@eslint/compat'
+import { FlatCompat } from '@eslint/eslintrc'
+import js from '@eslint/js'
+import typescriptEslint from '@typescript-eslint/eslint-plugin'
+import tsParser from '@typescript-eslint/parser'
+import _import from 'eslint-plugin-import'
+import n from 'eslint-plugin-n'
+import simpleImportSort from 'eslint-plugin-simple-import-sort'
+import globals from 'globals'
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = path.dirname(__filename)
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all,
+})
+
+export default [
+  ...fixupConfigRules(
+    compat.extends(
+      'eslint:recommended',
+      'plugin:import/typescript',
+      'plugin:@typescript-eslint/eslint-recommended',
+      'plugin:@typescript-eslint/recommended'
+    )
+  ),
+  {
+    plugins: {
+      import: fixupPluginRules(_import),
+      'simple-import-sort': simpleImportSort,
+      n,
+      '@typescript-eslint': fixupPluginRules(typescriptEslint),
+    },
+
+    languageOptions: {
+      globals: {
+        ...globals.node,
+      },
+
+      parser: tsParser,
+      ecmaVersion: 5,
+      sourceType: 'commonjs',
+    },
+
+    rules: {
+      'import/no-cycle': 'error',
+      'n/no-extraneous-import': 'error',
+      '@typescript-eslint/ban-ts-ignore': 'off',
+      '@typescript-eslint/ban-ts-comment': 'off',
+      '@typescript-eslint/explicit-module-boundary-types': 'off',
+      '@typescript-eslint/explicit-function-return-type': 'off',
+      '@typescript-eslint/no-use-before-define': 'off',
+      '@typescript-eslint/interface-name-prefix': 'off',
+      '@typescript-eslint/member-delimiter-style': 'off',
+      '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'error',
+      'simple-import-sort/imports': 'error',
+      'simple-import-sort/exports': 'error',
+    },
+  },
+  {
+    files: ['test/**'],
+
+    rules: {
+      '@typescript-eslint/no-non-null-assertion': 'off',
+    },
+  },
+]