chore: add eslint flat config

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

eslint.config.js

@@ -0,0 +1,61 @@
+// SPDX-FileCopyrightText: 2026 LibreCode coop and contributors
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+const js = require('@eslint/js')
+const vue = require('eslint-plugin-vue')
+const tsPlugin = require('@typescript-eslint/eslint-plugin')
+const tsParser = require('@typescript-eslint/parser')
+const vueParser = require('vue-eslint-parser')
+const vitest = require('eslint-plugin-vitest')
+
+const vitestGlobals = {
+  afterAll: 'readonly',
+  afterEach: 'readonly',
+  beforeAll: 'readonly',
+  beforeEach: 'readonly',
+  describe: 'readonly',
+  expect: 'readonly',
+  it: 'readonly',
+  test: 'readonly',
+  vi: 'readonly',
+}
+
+module.exports = [
+  {
+    ignores: ['dist/**', 'dist-demo/**', 'node_modules/**'],
+  },
+  js.configs.recommended,
+  {
+    files: ['**/*.{js,ts,vue}'],
+    languageOptions: {
+      parser: vueParser,
+      parserOptions: {
+        parser: tsParser,
+        ecmaVersion: 2021,
+        sourceType: 'module',
+      },
+    },
+    plugins: {
+      vue,
+      '@typescript-eslint': tsPlugin,
+    },
+    rules: {
+      ...vue.configs['flat/essential'].rules,
+      ...tsPlugin.configs.recommended.rules,
+      'no-console': process.env.NODE_ENV === 'production' ? 'warn' : 'off',
+      'no-debugger': process.env.NODE_ENV === 'production' ? 'warn' : 'off',
+    },
+  },
+  {
+    files: ['tests/**/*.ts'],
+    plugins: {
+      vitest,
+    },
+    languageOptions: {
+      globals: vitestGlobals,
+    },
+    rules: {
+      ...(vitest.configs?.recommended?.rules || {}),
+    },
+  },
+]

package.json

@@ -47,6 +47,7 @@
   },
   "devDependencies": {
     "@nextcloud/browserslist-config": "^3.1.2",
+    "@eslint/js": "^9.39.3",
     "@typescript-eslint/eslint-plugin": "^8.56.0",
     "@typescript-eslint/parser": "^8.56.0",
     "@vitejs/plugin-vue": "^6.0.4",