upgrade eslint, migrate to esm and flat config

frontend/.vscode/settings.json

@@ -20,11 +20,17 @@
   "html.format.wrapLineLength": 0,
   "typescript.preferences.importModuleSpecifier": "relative",
   "typescript.preferences.quoteStyle": "single",
+  "mochaExplorer.nodeArgv": [
+    "--loader=ts-node/esm",
+    "--no-warnings=ExperimentalWarning",
+    "--experimental-specifier-resolution=node"
+  ],
   "mochaExplorer.env": {
-    "TS_NODE_COMPILER_OPTIONS": "{\"module\": \"commonjs\" }",
+    //"TS_NODE_COMPILER_OPTIONS": "{\"module\": \"commonjs\" }",
     // "TS_NODE_PROJECT": "./test/tsconfig.json"
   },
   "mochaExplorer.files": "test/**/*.spec.ts",
   "mochaExplorer.require": "ts-node/register",
-  "eslint.validate": ["typescript", "javascript", "vue"]
+  "eslint.validate": ["typescript", "javascript", "vue"],
+  "eslint.useFlatConfig": true
 }

frontend/eslint.config.js

@@ -0,0 +1,97 @@
+// @ts-check
+import eslint from "@eslint/js";
+import pluginVue from 'eslint-plugin-vue';
+import tseslint from 'typescript-eslint';
+
+export default tseslint.config(
+{
+    files: ['src/**/*.ts', 'test/**/*.ts'],
+    extends: [
+        eslint.configs.recommended,
+        ...tseslint.configs.recommended,
+    ],
+    plugins: {
+        '@typescript-eslint': tseslint.plugin,
+    },
+    languageOptions: {
+        parser: tseslint.parser,
+        parserOptions: {
+            projectService: true,
+            tsconfigRootDir: import.meta.dirname,
+            ecmaVersion: 'latest',
+            sourceType: 'module',
+        },
+    },
+    rules: {
+        '@typescript-eslint/ban-ts-comment': 'warn',
+        '@typescript-eslint/no-explicit-any': 'warn',
+        '@typescript-eslint/no-unsafe-function-type': 'warn',
+        '@typescript-eslint/no-unused-vars': 'off', // is checked by noUnusedLocals in tsconfig.json // or use ['error', { 'ignoreRestSiblings': true }]
+        'no-unused-vars': 'off', // is checked by noUnusedLocals in tsconfig.json
+        'no-undef': 'off', // types checked by typescript already
+        'keyword-spacing': ['error', { before: true, after: true}],
+        'linebreak-style': ['error', 'unix'],
+        'lines-between-class-members': ['error', 'always', { exceptAfterSingleLine: true, }],
+        'no-multiple-empty-lines': ['error', { max: 1, maxEOF: 0, maxBOF: 0 }],
+        'object-curly-spacing': ['error', 'always'],
+        'padded-blocks': ['error', 'never'],
+        'quotes': ['error', 'single'],
+        'semi': ['error', 'always'],
+        'space-infix-ops': 'error',
+        'indent': ['error', 2, { SwitchCase: 1 }],
+    }
+},
+{
+    files: ['test/**/*.ts'],
+    rules: {
+        '@typescript-eslint/no-unused-expressions': 'off'
+    }
+},
+{
+    files: ['src/**/*.vue'],
+    extends: [
+        eslint.configs.recommended,
+        ...tseslint.configs.recommended,
+        ...pluginVue.configs["flat/recommended"],
+    ],
+    plugins: {
+        '@typescript-eslint': tseslint.plugin,
+    },
+    languageOptions: {
+        parserOptions: {
+            parser: tseslint.parser,
+            ecmaVersion: 'latest',
+            sourceType: 'module',
+            extraFileExtensions: ['.vue'],
+            ecmaFeatures: {
+                jsx: true
+            }
+        },
+    },
+    rules: {
+        '@typescript-eslint/ban-ts-comment': 'warn',
+        '@typescript-eslint/no-explicit-any': 'warn',
+        '@typescript-eslint/no-unsafe-function-type': 'warn',
+        '@typescript-eslint/no-unused-vars': 'off', // is checked by noUnusedLocals in tsconfig.json // or use ['error', { 'ignoreRestSiblings': true }]
+        'no-unused-vars': 'off', // is checked by noUnusedLocals in tsconfig.json
+        'no-undef': 'off', // types checked by typescript already
+        'keyword-spacing': ['error', { before: true, after: true}],
+        'linebreak-style': ['error', 'unix'],
+        'lines-between-class-members': ['error', 'always', { exceptAfterSingleLine: true, }],
+        'no-multiple-empty-lines': ['error', { max: 1, maxEOF: 0, maxBOF: 0 }],
+        'object-curly-spacing': ['error', 'always'],
+        'padded-blocks': ['error', 'never'],
+        'quotes': ['error', 'single'],
+        'semi': ['error', 'always'],
+        'space-infix-ops': 'error',
+        'indent': ['error', 2, { SwitchCase: 1 }],
+        'vue/block-tag-newline': ['error', { singleline: 'consistent', multiline: 'consistent', }],
+        'vue/html-closing-bracket-spacing': 'off',
+        'vue/html-self-closing': 'off',
+        'vue/max-attributes-per-line': 'off',
+        'vue/padding-line-between-blocks': 'error',
+        'vue/singleline-html-element-content-newline': 'off',
+        'vue/space-infix-ops': 'error',
+    },
+}
+);