eslint@9, remove resolutions and react-app

.gitignore

@@ -12,3 +12,5 @@ yarn-error.log*
 !.yarn/plugins
 !.yarn/sdks
 !.yarn/versions
+
+.eslintcache

configs.mjs

@@ -0,0 +1,25 @@
+// @ts-check
+
+import basicConfig from './lib/basic.mjs'
+import stylisticConfig from './lib/style.mjs'
+import typescriptConfig from './lib/typescript.mjs'
+import reactConfig from './lib/react.mjs'
+
+/** @type {import('eslint').Linter.Config[]} */
+const base = [
+  ...stylisticConfig,
+  ...basicConfig,
+  // Using a @type comment before a parenthesized expression like this is a
+  // type cast (like doing "as …" in TypeScript). Unsure why these types are
+  // incompatible though.
+  ...(/** @type {import('eslint').Linter.Config[]} */ (typescriptConfig)),
+]
+
+/** @type {import('eslint').Linter.Config[]} */
+export const basic = base
+
+/** @type {import('eslint').Linter.Config[]} */
+export const react = [
+  ...base,
+  ...reactConfig,
+]

eslint-plugin-react.d.ts

@@ -0,0 +1,39 @@
+// Non-exhaustive.
+declare module 'eslint-plugin-react' {
+  import type { ESLint, Linter } from 'eslint'
+
+  const plugin: ESLint.Plugin & {
+    configs: {
+      flat: {
+        all: Linter.Config
+        recommended: Linter.Config
+        'jsx-runtime': Linter.Config
+      }
+    }
+  }
+
+  export default plugin
+}
+
+declare module 'eslint-plugin-react-hooks' {
+  import type { ESLint, Rule, Linter } from 'eslint'
+
+  const plugin: ESLint.Plugin & {
+    configs: { recommended: Linter.Config }
+    rules: {
+      'rules-of-hooks': Rule.RuleModule
+      'exhaustive-deps': Rule.RuleModule
+    }
+  }
+  export default plugin
+}
+
+// Non-exhaustive.
+declare module 'eslint-plugin-import' {
+  import type { Linter } from 'eslint'
+
+  export const flatConfigs: {
+    typescript: Linter.Config
+    recommended: Linter.Config
+  }
+}

eslint.config.mjs

@@ -0,0 +1,8 @@
+/*
+ * WARNING: This ESLint config file should only be used while you are developing
+ * this ESLint config. In other words, this lets us lint the lint config with
+ * itself. If you want to _consume_ the ESLint configs exported by this
+ * package, just import it and use it within a flat config.
+ */
+
+export { basic as default } from './configs.mjs'

lib/basic.mjs

@@ -0,0 +1,104 @@
+// @ts-check
+
+import { fileURLToPath } from 'node:url'
+import path from 'node:path'
+
+import { fixupPluginRules } from '@eslint/compat'
+import { FlatCompat } from '@eslint/eslintrc'
+import js from '@eslint/js'
+import eslintPluginImport from 'eslint-plugin-import'
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = path.dirname(__filename)
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+  recommendedConfig: js.configs.recommended,
+})
+
+// https://github.com/import-js/eslint-plugin-import/issues/2948#issuecomment-2148832701
+/**
+  * @param {string} name
+  * @param {string} alias
+  * @returns {import('eslint').ESLint.Plugin}
+  */
+function legacyPlugin(name, alias = name) {
+  const plugin = compat.plugins(name)[0]?.plugins?.[alias]
+  if (!plugin) throw new Error(`Unable to resolve plugin ${name} and/or alias ${alias}`)
+  return fixupPluginRules(plugin)
+}
+
+const WARNING_IN_CI_ONLY = process.env.CI ? 'warn' : 'off'
+
+/** @type {import('eslint').Linter.Config[]} */
+export const importPlugin = [
+  { ...eslintPluginImport.flatConfigs.recommended, plugins: {} },
+  // TypeScript one doesn't have a name, but recommended does.
+  { ...eslintPluginImport.flatConfigs.typescript, name: 'import/typescript', plugins: {} },
+
+  {
+    name: '@textshq/eslint-config.basic.import',
+    plugins: { import: legacyPlugin('eslint-plugin-import', 'import') },
+    settings: {
+      'import/parsers': {
+        '@typescript-eslint/parser': ['.ts', '.tsx'],
+      },
+      'import/resolver': {
+        typescript: {
+          alwaysTryTypes: true,
+        },
+        node: true,
+      },
+    },
+    rules: {
+      // https://typescript-eslint.io/troubleshooting/typed-linting/performance#eslint-plugin-import
+      'import/named': 'off',
+      'import/namespace': 'off',
+      'import/default': 'off',
+      'import/no-named-as-default-member': 'off',
+      'import/no-unresolved': 'off',
+      'import/no-named-as-default': WARNING_IN_CI_ONLY,
+      'import/no-cycle': WARNING_IN_CI_ONLY,
+      'import/no-unused-modules': WARNING_IN_CI_ONLY,
+      'import/no-deprecated': WARNING_IN_CI_ONLY,
+    },
+  },
+]
+
+/** @type {import('eslint').Linter.Config[]} */
+const config = [
+  // Using a @type comment before a parenthesized expression like this is a
+  // type cast (like doing "as …" in TypeScript).
+
+  { ...js.configs.recommended, name: '@eslint/js/recommended' },
+
+  {
+    name: '@textshq/eslint-config.basic',
+    rules: {
+      // NOTE: Stylistic rules such as `semi` and `arrow-parens` have been
+      // deprecated in mainline ESLint and now live in ESLint Stylistic
+      // (https://eslint.style/) instead. This is configured in style.mjs.
+      'no-constant-binary-expression': 'error',
+      'no-param-reassign': 'warn',
+      'import/no-webpack-loader-syntax': 'off',
+      'import/prefer-default-export': 'off',
+      camelcase: 'off',
+      'consistent-return': 'off',
+      'max-classes-per-file': 'off',
+      'no-alert': 'off',
+      'no-await-in-loop': 'off',
+      'no-bitwise': 'off',
+      'no-console': 'off',
+      'no-continue': 'off',
+      'no-nested-ternary': 'off',
+      'no-new': 'off',
+      'no-plusplus': 'off',
+      'no-restricted-syntax': 'off',
+      'no-underscore-dangle': 'off',
+      'prefer-template': 'off',
+    },
+  },
+
+  ...importPlugin,
+]
+
+export default config

lib/react.mjs

@@ -0,0 +1,53 @@
+// @ts-check
+
+import eslintPluginJsxA11y from 'eslint-plugin-jsx-a11y'
+import eslintPluginReact from 'eslint-plugin-react'
+import eslintPluginReactHooks from 'eslint-plugin-react-hooks'
+
+/** @type {import('eslint').Linter.Config[]} */
+const config = [
+  eslintPluginJsxA11y.flatConfigs.recommended,
+  { ...eslintPluginReact.configs.flat.recommended, name: 'eslint-plugin-react/recommended' },
+
+  {
+    name: '@textshq/eslint-config.react',
+    plugins: {
+      react: eslintPluginReact,
+      'react-hooks': eslintPluginReactHooks,
+    },
+    languageOptions: {
+      parserOptions: {
+        jsx: true,
+      },
+    },
+    settings: {
+      react: {
+        version: '18.2',
+      },
+    },
+    rules: {
+      'jsx-a11y/anchor-is-valid': 'off',
+      'jsx-a11y/click-events-have-key-events': 'off',
+      'jsx-a11y/control-has-associated-label': 'warn',
+      'jsx-a11y/label-has-associated-control': 'warn',
+      'jsx-a11y/media-has-caption': 'off',
+      'jsx-a11y/no-autofocus': 'off',
+      'jsx-a11y/no-noninteractive-element-interactions': 'warn',
+      'jsx-a11y/no-static-element-interactions': 'off',
+      'react/function-component-definition': 'off',
+      'react/jsx-key': 'warn',
+      'react/jsx-one-expression-per-line': 'off',
+      'react/jsx-props-no-spreading': 'off',
+      'react/no-array-index-key': 'off',
+      'react/prop-types': 'off',
+      'react/react-in-jsx-scope': 'off',
+
+      // eslint-plugin-react-hooks supports ESLint v9, but doesn't export a
+      // flat config. We can just inline the recommended (legacy) config's
+      // rules here.
+      ...eslintPluginReactHooks.configs.recommended.rules,
+    },
+  },
+]
+
+export default config

lib/style.mjs

@@ -0,0 +1,47 @@
+// @ts-check
+
+import stylistic from '@stylistic/eslint-plugin'
+
+// N.B. The <true> means "we're using ESLint flat config". Parameterization is
+// important because the types would be different otherwise.
+
+/** @type {import('@stylistic/eslint-plugin').StylisticCustomizeOptions<true>} */
+export const stylisticCustomizationOptions = {
+  indent: 2,
+  quotes: 'single',
+  semi: false,
+  braceStyle: '1tbs',
+}
+
+/** @type {import('@stylistic/eslint-plugin').StylisticCustomizeOptions<true>} */
+export const stylisticCustomizationOptionsJSX = {
+  ...stylisticCustomizationOptions,
+  jsx: true,
+}
+
+/** @type {import('eslint').Linter.Config[]} */
+const config = [
+  // "Recommended" rules added by this call: https://github.com/eslint-stylistic/eslint-stylistic/blob/ff6905308fa7cca27b0131d27e0c8f5b964ecb5a/packages/eslint-plugin/configs/customize.ts#L33
+  { ...stylistic.configs.customize(stylisticCustomizationOptions), name: '@stylistic/eslint-plugin' },
+
+  {
+    name: '@textshq/eslint-config.stylistic',
+    rules: {
+      '@stylistic/quotes': ['error', 'single', { avoidEscape: true }],
+      '@stylistic/semi': ['error', 'never'],
+      '@stylistic/arrow-parens': ['error', 'as-needed'],
+      '@stylistic/implicit-arrow-linebreak': 'off',
+      '@stylistic/max-len': 'off',
+      '@stylistic/newline-per-chained-call': 'off',
+      '@stylistic/object-curly-newline': 'off',
+      '@stylistic/member-delimiter-style': ['error', {
+        multiline: { delimiter: 'none' },
+        singleline: { delimiter: 'comma' },
+      }],
+      '@stylistic/quote-props': ['warn', 'as-needed'],
+    },
+  },
+
+]
+
+export default config