Add ESLint.

Author: longwave

eslint.config.js

@@ -0,0 +1,44 @@
+import js from '@eslint/js'
+import typescript from '@typescript-eslint/eslint-plugin'
+import typescriptParser from '@typescript-eslint/parser'
+
+export default [
+  js.configs.recommended,
+  {
+    files: ['src/**/*.ts', 'src/**/*.tsx', 'test/**/*.ts', 'test/**/*.tsx'],
+    languageOptions: {
+      parser: typescriptParser,
+      parserOptions: {
+        ecmaVersion: 'latest',
+        sourceType: 'module',
+      },
+      globals: {
+        // Node.js
+        console: 'readonly',
+        process: 'readonly',
+        URL: 'readonly',
+        fetch: 'readonly',
+        // Browser
+        window: 'readonly',
+        document: 'readonly',
+        HTMLElement: 'readonly',
+        HTMLImageElement: 'readonly',
+        HTMLAnchorElement: 'readonly',
+        // React
+        React: 'readonly',
+      },
+    },
+    plugins: {
+      '@typescript-eslint': typescript,
+    },
+    rules: {
+      ...typescript.configs.recommended.rules,
+      '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
+      'no-unused-vars': 'off',
+    },
+  },
+  {
+    ignores: ['dist/', 'node_modules/'],
+  },
+]