diff --git a/.eslintignore b/.eslintignore
deleted file mode 100644
index 13d8c5b..0000000
--- a/.eslintignore
+++ /dev/null
@@ -1,6 +0,0 @@
-.vscode-test-web
-coverage
-lib
-dist
-preview
-node_modules
diff --git a/.eslintrc.js b/.eslintrc.js
deleted file mode 100644
index 1916415..0000000
--- a/.eslintrc.js
+++ /dev/null
@@ -1,41 +0,0 @@
-module.exports = {
-  root: true,
-  env: {
-    browser: true,
-    node: true,
-  },
-  extends: ['eslint:recommended', 'plugin:import/recommended', 'prettier'],
-  rules: {
-    'import/order': ['error', { alphabetize: { order: 'asc' } }],
-  },
-  settings: {
-    'import/resolver': { typescript: { alwaysTryTypes: true } },
-  },
-  overrides: [
-    {
-      files: ['**/*.ts'],
-      parser: '@typescript-eslint/parser',
-      plugins: ['@typescript-eslint'],
-      extends: [
-        'plugin:@typescript-eslint/recommended',
-        'plugin:@typescript-eslint/stylistic',
-        'plugin:import/typescript',
-        'prettier',
-      ],
-      rules: {
-        '@typescript-eslint/no-explicit-any': 'off',
-        '@typescript-eslint/explicit-function-return-type': 'off',
-        '@typescript-eslint/explicit-module-boundary-types': 'off',
-      },
-      parserOptions: {
-        project: true,
-        tsconfigRootDir: __dirname,
-      },
-    },
-    {
-      files: ['**/*.test.js', '**/*.test.ts'],
-      plugins: ['jest'],
-      extends: ['plugin:jest/recommended', 'plugin:jest/style'],
-    },
-  ],
-}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 94a0a91..6c500ff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,7 +12,8 @@
 
 ### Changed
 
-- Upgrade dependent packages to the latest version ([#474](https://github.com/marp-team/marp-vscode/pull/474))
+- Upgrade development Node.js and dependent packages to the latest version ([#474](https://github.com/marp-team/marp-vscode/pull/474))
+- Migrate ESLint config to flat config ([#475](https://github.com/marp-team/marp-vscode/pull/475))
 
 ## v2.8.0 - 2023-10-28
 
diff --git a/eslint.config.mjs b/eslint.config.mjs
new file mode 100644
index 0000000..34be26a
--- /dev/null
+++ b/eslint.config.mjs
@@ -0,0 +1,86 @@
+import js from '@eslint/js'
+import eslintConfigPrettier from 'eslint-config-prettier'
+import eslintPluginImport from 'eslint-plugin-import'
+import eslintPluginJest from 'eslint-plugin-jest'
+import eslintPluginUnicorn from 'eslint-plugin-unicorn'
+import globals from 'globals'
+import tseslint from 'typescript-eslint'
+
+const tsFiles = ['**/*.ts', '**/*.tsx', '**/*.mts', '**/*.cts']
+const testFiles = [
+  '**/*.test.ts',
+  '**/*.test.tsx',
+  '**/*.test.mts',
+  '**/*.test.cts',
+  'jest.setup.js',
+]
+
+const forFiles = (files, confs) => confs.map((conf) => ({ ...conf, files }))
+
+export default tseslint.config(
+  js.configs.recommended,
+  eslintPluginImport.flatConfigs.recommended,
+  {
+    plugins: {
+      unicorn: eslintPluginUnicorn,
+    },
+    rules: {
+      'unicorn/prefer-node-protocol': 'error',
+    },
+  },
+  ...forFiles(tsFiles, [
+    ...tseslint.configs.recommended,
+    ...tseslint.configs.stylistic,
+    {
+      extends: [eslintPluginImport.flatConfigs.recommended],
+    },
+    {
+      rules: {
+        '@typescript-eslint/no-explicit-any': 'off',
+        '@typescript-eslint/explicit-function-return-type': 'off',
+        '@typescript-eslint/explicit-module-boundary-types': 'off',
+        '@typescript-eslint/consistent-type-assertions': [
+          'error',
+          { assertionStyle: 'as' },
+        ],
+      },
+    },
+  ]),
+  ...forFiles(testFiles, [
+    eslintPluginJest.configs['flat/recommended'],
+    eslintPluginJest.configs['flat/style'],
+    { languageOptions: { globals: { ...globals.jest } } },
+  ]),
+  eslintConfigPrettier,
+  {
+    linterOptions: {
+      reportUnusedDisableDirectives: 'error',
+    },
+    languageOptions: {
+      ecmaVersion: 'latest',
+      parserOptions: {
+        ecmaFeatures: { jsx: true },
+      },
+      globals: {
+        ...globals.node,
+        ...globals.browser,
+      },
+    },
+    rules: {
+      'import/order': ['error', { alphabetize: { order: 'asc' } }],
+    },
+    settings: {
+      'import/resolver': { typescript: { alwaysTryTypes: true } },
+    },
+  },
+  {
+    ignores: [
+      '.vscode-test-web/**/*',
+      'coverage/**/*',
+      'dist/**/*',
+      'lib/**/*',
+      'node_modules/**/*',
+      'preview/**/*',
+    ],
+  },
+)
diff --git a/jest.setup.js b/jest.setup.js
index 71340e4..f95eef2 100644
--- a/jest.setup.js
+++ b/jest.setup.js
@@ -1,4 +1,4 @@
-import { TextEncoder, TextDecoder } from 'util'
+import { TextEncoder, TextDecoder } from 'node:util'
 
 // TextEncoder and TextDecoder are exposed to global in Node.js and the browser.
 // Jest VM for testing seems not to expose them to JSDOM.
diff --git a/package-lock.json b/package-lock.json
index d2d47a2..6ba86dc 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -13,6 +13,7 @@
       },
       "devDependencies": {
         "@babel/preset-env": "^7.26.0",
+        "@eslint/js": "^9.17.0",
         "@marp-team/marp-core": "^4.0.1",
         "@types/color-string": "^1.5.5",
         "@types/express": "^4.17.21",
@@ -20,8 +21,6 @@
         "@types/lodash.debounce": "^4.0.9",
         "@types/markdown-it": "^14.1.2",
         "@types/vscode": "~1.86.0",
-        "@typescript-eslint/eslint-plugin": "^8.18.2",
-        "@typescript-eslint/parser": "^8.18.2",
         "@vscode/test-web": "^0.0.65",
         "@vscode/vsce": "^3.2.1",
         "abort-controller": "^3.0.0",
@@ -34,8 +33,10 @@
         "eslint-import-resolver-typescript": "^3.7.0",
         "eslint-plugin-import": "^2.31.0",
         "eslint-plugin-jest": "^28.10.0",
+        "eslint-plugin-unicorn": "^56.0.1",
         "express": "^4.21.2",
         "fetch-ponyfill": "^7.1.0",
+        "globals": "^15.14.0",
         "jest": "^29.7.0",
         "jest-environment-jsdom": "^29.7.0",
         "jest-junit": "^16.0.0",
@@ -58,6 +59,7 @@
         "tslib": "^2.8.1",
         "typed-emitter": "^2.1.0",
         "typescript": "^5.7.2",
+        "typescript-eslint": "^8.18.2",
         "unified": "^11.0.5",
         "unist-util-visit": "^5.0.0",
         "util": "^0.12.5",
@@ -1115,6 +1117,16 @@
         "@babel/core": "^7.0.0-0"
       }
     },
+    "node_modules/@babel/plugin-transform-classes/node_modules/globals": {
+      "version": "11.12.0",
+      "resolved": "https://registry.npmjs.org/globals/-/globals-11.12.0.tgz",
+      "integrity": "sha512-WOBp/EEGUiIsJSp7wcv/y6MO+lV9UoncWqxuFfm8eBwzWNgyfBd6Gz+IeKQ9jCmyhoH99g15M3T+QaVHFjizVA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/@babel/plugin-transform-computed-properties": {
       "version": "7.25.9",
       "resolved": "https://registry.npmjs.org/@babel/plugin-transform-computed-properties/-/plugin-transform-computed-properties-7.25.9.tgz",
@@ -1959,6 +1971,16 @@
         "node": ">=6.9.0"
       }
     },
+    "node_modules/@babel/traverse/node_modules/globals": {
+      "version": "11.12.0",
+      "resolved": "https://registry.npmjs.org/globals/-/globals-11.12.0.tgz",
+      "integrity": "sha512-WOBp/EEGUiIsJSp7wcv/y6MO+lV9UoncWqxuFfm8eBwzWNgyfBd6Gz+IeKQ9jCmyhoH99g15M3T+QaVHFjizVA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/@babel/types": {
       "version": "7.26.3",
       "resolved": "https://registry.npmjs.org/@babel/types/-/types-7.26.3.tgz",
@@ -4338,6 +4360,13 @@
         "undici-types": "~6.20.0"
       }
     },
+    "node_modules/@types/normalize-package-data": {
+      "version": "2.4.4",
+      "resolved": "https://registry.npmjs.org/@types/normalize-package-data/-/normalize-package-data-2.4.4.tgz",
+      "integrity": "sha512-37i+OaWTh9qeK4LSHPsyRC7NahnGotNuZvjLSgcPzblpHB3rrCJxAOgI5gCdKm7coonsaX1Of0ILiTcnZjbfxA==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/qs": {
       "version": "6.9.17",
       "resolved": "https://registry.npmjs.org/@types/qs/-/qs-6.9.17.tgz",
@@ -6131,6 +6160,19 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/builtin-modules": {
+      "version": "3.3.0",
+      "resolved": "https://registry.npmjs.org/builtin-modules/-/builtin-modules-3.3.0.tgz",
+      "integrity": "sha512-zhaCDicdLuWN5UbN5IMnFqNMhNfo919sH85y2/ea+5Yg9TsTkeZxpL+JLbp6cgYFS4sRLp3YV4S6yDuqVWHYOw==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=6"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
     "node_modules/bytes": {
       "version": "3.1.2",
       "resolved": "https://registry.npmjs.org/bytes/-/bytes-3.1.2.tgz",
@@ -6394,6 +6436,19 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/clean-regexp": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/clean-regexp/-/clean-regexp-1.0.0.tgz",
+      "integrity": "sha512-GfisEZEJvzKrmGWkvfhgzcz/BllN1USeqD2V6tg14OAOgaCD2Z/PUEuxnAZ/nPvmaHRG7a8y77p1T/IRQ4D1Hw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "escape-string-regexp": "^1.0.5"
+      },
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/cliui": {
       "version": "8.0.1",
       "resolved": "https://registry.npmjs.org/cliui/-/cliui-8.0.1.tgz",
@@ -8540,6 +8595,91 @@
         }
       }
     },
+    "node_modules/eslint-plugin-unicorn": {
+      "version": "56.0.1",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-unicorn/-/eslint-plugin-unicorn-56.0.1.tgz",
+      "integrity": "sha512-FwVV0Uwf8XPfVnKSGpMg7NtlZh0G0gBarCaFcMUOoqPxXryxdYxTRRv4kH6B9TFCVIrjRXG+emcxIk2ayZilog==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@babel/helper-validator-identifier": "^7.24.7",
+        "@eslint-community/eslint-utils": "^4.4.0",
+        "ci-info": "^4.0.0",
+        "clean-regexp": "^1.0.0",
+        "core-js-compat": "^3.38.1",
+        "esquery": "^1.6.0",
+        "globals": "^15.9.0",
+        "indent-string": "^4.0.0",
+        "is-builtin-module": "^3.2.1",
+        "jsesc": "^3.0.2",
+        "pluralize": "^8.0.0",
+        "read-pkg-up": "^7.0.1",
+        "regexp-tree": "^0.1.27",
+        "regjsparser": "^0.10.0",
+        "semver": "^7.6.3",
+        "strip-indent": "^3.0.0"
+      },
+      "engines": {
+        "node": ">=18.18"
+      },
+      "funding": {
+        "url": "https://github.com/sindresorhus/eslint-plugin-unicorn?sponsor=1"
+      },
+      "peerDependencies": {
+        "eslint": ">=8.56.0"
+      }
+    },
+    "node_modules/eslint-plugin-unicorn/node_modules/ci-info": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/ci-info/-/ci-info-4.1.0.tgz",
+      "integrity": "sha512-HutrvTNsF48wnxkzERIXOe5/mlcfFcbfCmwcg6CJnizbSue78AbDt+1cgl26zwn61WFxhcPykPfZrbqjGmBb4A==",
+      "dev": true,
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/sibiraj-s"
+        }
+      ],
+      "license": "MIT",
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/eslint-plugin-unicorn/node_modules/regjsparser": {
+      "version": "0.10.0",
+      "resolved": "https://registry.npmjs.org/regjsparser/-/regjsparser-0.10.0.tgz",
+      "integrity": "sha512-qx+xQGZVsy55CH0a1hiVwHmqjLryfh7wQyF5HO07XJ9f7dQMY/gPQHhlyDkIzJKC+x2fUCpCcUODUUUFrm7SHA==",
+      "dev": true,
+      "license": "BSD-2-Clause",
+      "dependencies": {
+        "jsesc": "~0.5.0"
+      },
+      "bin": {
+        "regjsparser": "bin/parser"
+      }
+    },
+    "node_modules/eslint-plugin-unicorn/node_modules/regjsparser/node_modules/jsesc": {
+      "version": "0.5.0",
+      "resolved": "https://registry.npmjs.org/jsesc/-/jsesc-0.5.0.tgz",
+      "integrity": "sha512-uZz5UnB7u4T9LvwmFqXii7pZSouaRPorGs5who1Ip7VO0wxanFvBL7GkM6dTHlgX+jhBApRetaWpnDabOeTcnA==",
+      "dev": true,
+      "bin": {
+        "jsesc": "bin/jsesc"
+      }
+    },
+    "node_modules/eslint-plugin-unicorn/node_modules/semver": {
+      "version": "7.6.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.6.3.tgz",
+      "integrity": "sha512-oVekP1cKtI+CTDvHWYFUcMtsK/00wmAEfyqKfNdARm8u1wNVhSgaX7A8d4UuIlUI5e84iEwOhs7ZPYRmzU9U6A==",
+      "dev": true,
+      "license": "ISC",
+      "bin": {
+        "semver": "bin/semver.js"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/eslint-scope": {
       "version": "8.2.0",
       "resolved": "https://registry.npmjs.org/eslint-scope/-/eslint-scope-8.2.0.tgz",
@@ -9605,13 +9745,16 @@
       }
     },
     "node_modules/globals": {
-      "version": "11.12.0",
-      "resolved": "https://registry.npmjs.org/globals/-/globals-11.12.0.tgz",
-      "integrity": "sha512-WOBp/EEGUiIsJSp7wcv/y6MO+lV9UoncWqxuFfm8eBwzWNgyfBd6Gz+IeKQ9jCmyhoH99g15M3T+QaVHFjizVA==",
+      "version": "15.14.0",
+      "resolved": "https://registry.npmjs.org/globals/-/globals-15.14.0.tgz",
+      "integrity": "sha512-OkToC372DtlQeje9/zHIo5CT8lRP/FUgEOKBEhU4e0abL7J7CD24fD9ohiLN5hagG/kWCYj4K5oaxxtj2Z0Dig==",
       "dev": true,
       "license": "MIT",
       "engines": {
-        "node": ">=4"
+        "node": ">=18"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
       }
     },
     "node_modules/globalthis": {
@@ -10171,6 +10314,16 @@
         "node": ">=0.8.19"
       }
     },
+    "node_modules/indent-string": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/indent-string/-/indent-string-4.0.0.tgz",
+      "integrity": "sha512-EdDDZu4A2OyIK7Lr/2zG+w5jmbuk1DVBnEwREQvBzspBJkCEbRa8GxU1lghYcaGJCnRWibjDXlq779X1/y5xwg==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/inflight": {
       "version": "1.0.6",
       "resolved": "https://registry.npmjs.org/inflight/-/inflight-1.0.6.tgz",
@@ -10335,6 +10488,22 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/is-builtin-module": {
+      "version": "3.2.1",
+      "resolved": "https://registry.npmjs.org/is-builtin-module/-/is-builtin-module-3.2.1.tgz",
+      "integrity": "sha512-BSLE3HnV2syZ0FK0iMA/yUGplUeMmNz4AW5fnTunbCIqZi4vG3WjJT9FHMy5D69xmAYBHXQhJdALdpwVxV501A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "builtin-modules": "^3.3.0"
+      },
+      "engines": {
+        "node": ">=6"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
     "node_modules/is-bun-module": {
       "version": "1.3.0",
       "resolved": "https://registry.npmjs.org/is-bun-module/-/is-bun-module-1.3.0.tgz",
@@ -14472,6 +14641,16 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/min-indent": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/min-indent/-/min-indent-1.0.1.tgz",
+      "integrity": "sha512-I9jwMn07Sy/IwOj3zVkVik2JTvgpaykDZEigL6Rx6N9LbMywwUSMtxET+7lVoDLLd3O3IXwJwvuuns8UB/HeAg==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/minimatch": {
       "version": "9.0.5",
       "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-9.0.5.tgz",
@@ -14756,6 +14935,36 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/normalize-package-data": {
+      "version": "2.5.0",
+      "resolved": "https://registry.npmjs.org/normalize-package-data/-/normalize-package-data-2.5.0.tgz",
+      "integrity": "sha512-/5CMN3T0R4XTj4DcGaexo+roZSdSFW/0AOOTROrjxzCG1wrWXEsGbRKevjlIL+ZDE4sZlJr5ED4YW0yqmkK+eA==",
+      "dev": true,
+      "license": "BSD-2-Clause",
+      "dependencies": {
+        "hosted-git-info": "^2.1.4",
+        "resolve": "^1.10.0",
+        "semver": "2 || 3 || 4 || 5",
+        "validate-npm-package-license": "^3.0.1"
+      }
+    },
+    "node_modules/normalize-package-data/node_modules/hosted-git-info": {
+      "version": "2.8.9",
+      "resolved": "https://registry.npmjs.org/hosted-git-info/-/hosted-git-info-2.8.9.tgz",
+      "integrity": "sha512-mxIDAb9Lsm6DoOJ7xH+5+X4y1LU/4Hi50L9C5sIswK3JzULS4bwk1FvjdBgvYR4bzT4tuUQiC15FE2f5HbLvYw==",
+      "dev": true,
+      "license": "ISC"
+    },
+    "node_modules/normalize-package-data/node_modules/semver": {
+      "version": "5.7.2",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-5.7.2.tgz",
+      "integrity": "sha512-cBznnQ9KjJqU67B52RMC65CMarK2600WFnbkcaiwWq3xy/5haFJlshgnpjovMVJ+Hff49d8GEn0b87C5pDQ10g==",
+      "dev": true,
+      "license": "ISC",
+      "bin": {
+        "semver": "bin/semver"
+      }
+    },
     "node_modules/normalize-path": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/normalize-path/-/normalize-path-3.0.0.tgz",
@@ -15553,6 +15762,16 @@
         "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
       }
     },
+    "node_modules/pluralize": {
+      "version": "8.0.0",
+      "resolved": "https://registry.npmjs.org/pluralize/-/pluralize-8.0.0.tgz",
+      "integrity": "sha512-Nc3IT5yHzflTfbjgqWcCPpo7DaKy4FnpB0l/zCAW0Tc7jxAiuqSxHasntB3D7887LSrA93kDJ9IXovxJYxyLCA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/portfinder": {
       "version": "1.0.32",
       "resolved": "https://registry.npmjs.org/portfinder/-/portfinder-1.0.32.tgz",
@@ -16227,6 +16446,116 @@
         "node": "^18.17.0 || >=20.5.0"
       }
     },
+    "node_modules/read-pkg": {
+      "version": "5.2.0",
+      "resolved": "https://registry.npmjs.org/read-pkg/-/read-pkg-5.2.0.tgz",
+      "integrity": "sha512-Ug69mNOpfvKDAc2Q8DRpMjjzdtrnv9HcSMX+4VsZxD1aZ6ZzrIE7rlzXBtWTyhULSMKg076AW6WR5iZpD0JiOg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/normalize-package-data": "^2.4.0",
+        "normalize-package-data": "^2.5.0",
+        "parse-json": "^5.0.0",
+        "type-fest": "^0.6.0"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/read-pkg-up": {
+      "version": "7.0.1",
+      "resolved": "https://registry.npmjs.org/read-pkg-up/-/read-pkg-up-7.0.1.tgz",
+      "integrity": "sha512-zK0TB7Xd6JpCLmlLmufqykGE+/TlOePD6qKClNW7hHDKFh/J7/7gCWGR7joEQEW1bKq3a3yUZSObOoWLFQ4ohg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "find-up": "^4.1.0",
+        "read-pkg": "^5.2.0",
+        "type-fest": "^0.8.1"
+      },
+      "engines": {
+        "node": ">=8"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/read-pkg-up/node_modules/find-up": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/find-up/-/find-up-4.1.0.tgz",
+      "integrity": "sha512-PpOwAdQ/YlXQ2vj8a3h8IipDuYRi3wceVQQGYWxNINccq40Anw7BlsEXCMbt1Zt+OLA6Fq9suIpIWD0OsnISlw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "locate-path": "^5.0.0",
+        "path-exists": "^4.0.0"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/read-pkg-up/node_modules/locate-path": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/locate-path/-/locate-path-5.0.0.tgz",
+      "integrity": "sha512-t7hw9pI+WvuwNJXwk5zVHpyhIqzg2qTlklJOf0mVxGSbe3Fp2VieZcduNYjaLDoy6p9uGpQEGWG87WpMKlNq8g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "p-locate": "^4.1.0"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/read-pkg-up/node_modules/p-limit": {
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/p-limit/-/p-limit-2.3.0.tgz",
+      "integrity": "sha512-//88mFWSJx8lxCzwdAABTJL2MyWB12+eIY7MDL2SqLmAkeKU9qxRvWuSyTjm3FUmpBEMuFfckAIqEaVGUDxb6w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "p-try": "^2.0.0"
+      },
+      "engines": {
+        "node": ">=6"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/read-pkg-up/node_modules/p-locate": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/p-locate/-/p-locate-4.1.0.tgz",
+      "integrity": "sha512-R79ZZ/0wAxKGu3oYMlz8jy/kbhsNrS7SKZ7PxEHBgJ5+F2mtFW2fK2cOtBh1cHYkQsbzFV7I+EoRKe6Yt0oK7A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "p-limit": "^2.2.0"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/read-pkg-up/node_modules/type-fest": {
+      "version": "0.8.1",
+      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+      "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+      "dev": true,
+      "license": "(MIT OR CC0-1.0)",
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/read-pkg/node_modules/type-fest": {
+      "version": "0.6.0",
+      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.6.0.tgz",
+      "integrity": "sha512-q+MB8nYR1KDLrgr4G5yemftpMC7/QLqVndBmEEdqzmNj5dcFOO4Oo8qlwZE3ULT3+Zim1F8Kq4cBnikNhlCMlg==",
+      "dev": true,
+      "license": "(MIT OR CC0-1.0)",
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/readable-stream": {
       "version": "2.3.8",
       "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.8.tgz",
@@ -16336,6 +16665,16 @@
         "@babel/runtime": "^7.8.4"
       }
     },
+    "node_modules/regexp-tree": {
+      "version": "0.1.27",
+      "resolved": "https://registry.npmjs.org/regexp-tree/-/regexp-tree-0.1.27.tgz",
+      "integrity": "sha512-iETxpjK6YoRWJG5o6hXLwvjYAoW+FEZn9os0PD/b6AP6xQwsa/Y7lCVgIixBbUPMfhu+i2LtdeAqVTgGlQarfA==",
+      "dev": true,
+      "license": "MIT",
+      "bin": {
+        "regexp-tree": "bin/regexp-tree"
+      }
+    },
     "node_modules/regexp.prototype.flags": {
       "version": "1.5.3",
       "resolved": "https://registry.npmjs.org/regexp.prototype.flags/-/regexp.prototype.flags-1.5.3.tgz",
@@ -17369,6 +17708,42 @@
         "url": "https://github.com/sponsors/wooorm"
       }
     },
+    "node_modules/spdx-correct": {
+      "version": "3.2.0",
+      "resolved": "https://registry.npmjs.org/spdx-correct/-/spdx-correct-3.2.0.tgz",
+      "integrity": "sha512-kN9dJbvnySHULIluDHy32WHRUu3Og7B9sbY7tsFLctQkIqnMh3hErYgdMjTYuqmcXX+lK5T1lnUt3G7zNswmZA==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "spdx-expression-parse": "^3.0.0",
+        "spdx-license-ids": "^3.0.0"
+      }
+    },
+    "node_modules/spdx-exceptions": {
+      "version": "2.5.0",
+      "resolved": "https://registry.npmjs.org/spdx-exceptions/-/spdx-exceptions-2.5.0.tgz",
+      "integrity": "sha512-PiU42r+xO4UbUS1buo3LPJkjlO7430Xn5SVAhdpzzsPHsjbYVflnnFdATgabnLude+Cqu25p6N+g2lw/PFsa4w==",
+      "dev": true,
+      "license": "CC-BY-3.0"
+    },
+    "node_modules/spdx-expression-parse": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/spdx-expression-parse/-/spdx-expression-parse-3.0.1.tgz",
+      "integrity": "sha512-cbqHunsQWnJNE6KhVSMsMeH5H/L9EpymbzqTQ3uLwNCLZ1Q481oWaofqH7nO6V07xlXwY6PhQdQ2IedWx/ZK4Q==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "spdx-exceptions": "^2.1.0",
+        "spdx-license-ids": "^3.0.0"
+      }
+    },
+    "node_modules/spdx-license-ids": {
+      "version": "3.0.20",
+      "resolved": "https://registry.npmjs.org/spdx-license-ids/-/spdx-license-ids-3.0.20.tgz",
+      "integrity": "sha512-jg25NiDV/1fLtSgEgyvVyDunvaNHbuwF9lfNV17gSmPFAlYzdfNBlLtLzXTevwkPj7DhGbmN9VnmJIgLnhvaBw==",
+      "dev": true,
+      "license": "CC0-1.0"
+    },
     "node_modules/speech-rule-engine": {
       "version": "4.0.7",
       "resolved": "https://registry.npmjs.org/speech-rule-engine/-/speech-rule-engine-4.0.7.tgz",
@@ -17707,6 +18082,19 @@
         "node": ">=6"
       }
     },
+    "node_modules/strip-indent": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/strip-indent/-/strip-indent-3.0.0.tgz",
+      "integrity": "sha512-laJTa3Jb+VQpaC6DseHhF7dXVqHTfJPCRDaEbid/drOhgitgYku/letMUqOXFoWV0zIIUbjpdH2t+tYj4bQMRQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "min-indent": "^1.0.0"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/strip-json-comments": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-3.1.1.tgz",
@@ -18802,6 +19190,29 @@
         "node": ">=14.17"
       }
     },
+    "node_modules/typescript-eslint": {
+      "version": "8.18.2",
+      "resolved": "https://registry.npmjs.org/typescript-eslint/-/typescript-eslint-8.18.2.tgz",
+      "integrity": "sha512-KuXezG6jHkvC3MvizeXgupZzaG5wjhU3yE8E7e6viOvAvD9xAWYp8/vy0WULTGe9DYDWcQu7aW03YIV3mSitrQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/eslint-plugin": "8.18.2",
+        "@typescript-eslint/parser": "8.18.2",
+        "@typescript-eslint/utils": "8.18.2"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "eslint": "^8.57.0 || ^9.0.0",
+        "typescript": ">=4.8.4 <5.8.0"
+      }
+    },
     "node_modules/uc.micro": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/uc.micro/-/uc.micro-2.1.0.tgz",
@@ -19133,6 +19544,17 @@
         "node": ">=10.12.0"
       }
     },
+    "node_modules/validate-npm-package-license": {
+      "version": "3.0.4",
+      "resolved": "https://registry.npmjs.org/validate-npm-package-license/-/validate-npm-package-license-3.0.4.tgz",
+      "integrity": "sha512-DpKm2Ui/xN7/HQKCtpZxoRWBhZ9Z0kqtygG8XCgNQ8ZlDnxuQmWhj566j8fN4Cu3/JmbhsDo7fcAJq4s9h27Ew==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "spdx-correct": "^3.0.0",
+        "spdx-expression-parse": "^3.0.0"
+      }
+    },
     "node_modules/vary": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/vary/-/vary-1.1.2.tgz",
diff --git a/package.json b/package.json
index 25e2496..e08a889 100644
--- a/package.json
+++ b/package.json
@@ -259,7 +259,7 @@
     "format": "prettier \"**/*.{css,js,json,md,scss,ts,yaml,yml}\"",
     "format:write": "npm run -s format -- --write",
     "lint:css": "stylelint \"./*.{css,scss}\"",
-    "lint:js": "ESLINT_USE_FLAT_CONFIG=false eslint --ext .js,.ts --report-unused-disable-directives --cache .",
+    "lint:js": "eslint --cache",
     "package": "vsce package",
     "preversion": "run-p check:* lint:* test:*:coverage",
     "test:unit": "jest",
@@ -273,6 +273,7 @@
   },
   "devDependencies": {
     "@babel/preset-env": "^7.26.0",
+    "@eslint/js": "^9.17.0",
     "@marp-team/marp-core": "^4.0.1",
     "@types/color-string": "^1.5.5",
     "@types/express": "^4.17.21",
@@ -280,8 +281,6 @@
     "@types/lodash.debounce": "^4.0.9",
     "@types/markdown-it": "^14.1.2",
     "@types/vscode": "~1.86.0",
-    "@typescript-eslint/eslint-plugin": "^8.18.2",
-    "@typescript-eslint/parser": "^8.18.2",
     "@vscode/test-web": "^0.0.65",
     "@vscode/vsce": "^3.2.1",
     "abort-controller": "^3.0.0",
@@ -294,8 +293,10 @@
     "eslint-import-resolver-typescript": "^3.7.0",
     "eslint-plugin-import": "^2.31.0",
     "eslint-plugin-jest": "^28.10.0",
+    "eslint-plugin-unicorn": "^56.0.1",
     "express": "^4.21.2",
     "fetch-ponyfill": "^7.1.0",
+    "globals": "^15.14.0",
     "jest": "^29.7.0",
     "jest-environment-jsdom": "^29.7.0",
     "jest-junit": "^16.0.0",
@@ -318,6 +319,7 @@
     "tslib": "^2.8.1",
     "typed-emitter": "^2.1.0",
     "typescript": "^5.7.2",
+    "typescript-eslint": "^8.18.2",
     "unified": "^11.0.5",
     "unist-util-visit": "^5.0.0",
     "util": "^0.12.5",
diff --git a/src/commands/export.ts b/src/commands/export.ts
index 8f5f759..71c6ab4 100644
--- a/src/commands/export.ts
+++ b/src/commands/export.ts
@@ -1,5 +1,5 @@
-import { tmpdir } from 'os'
-import path from 'path'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
 import { nanoid } from 'nanoid'
 import {
   commands,
diff --git a/src/directives/parser.ts b/src/directives/parser.ts
index 494b37e..d2afdcc 100644
--- a/src/directives/parser.ts
+++ b/src/directives/parser.ts
@@ -1,11 +1,11 @@
-import { EventEmitter } from 'events'
+import { EventEmitter } from 'node:events'
 import type { Root as RehypeRoot } from 'hast'
 import rehypeParse from 'rehype-parse'
 import remarkMath from 'remark-math'
 import remarkParse from 'remark-parse'
 import type { Root as RemarkRoot } from 'remark-parse/lib'
 import TypedEmitter from 'typed-emitter'
-import { Processor, unified } from 'unified'
+import { type Processor, unified } from 'unified'
 import { visit } from 'unist-util-visit'
 import { Range, TextDocument } from 'vscode'
 import yaml, { Pair, Scalar, YAMLMap } from 'yaml'
diff --git a/src/extension.test.ts b/src/extension.test.ts
index 30ab62f..675e23b 100644
--- a/src/extension.test.ts
+++ b/src/extension.test.ts
@@ -1,6 +1,6 @@
 /** @jest-environment jsdom */
-import path from 'path'
-import { TextEncoder } from 'util'
+import path from 'node:path'
+import { TextEncoder } from 'node:util'
 import { Marp } from '@marp-team/marp-core'
 import dedent from 'dedent'
 import markdownIt from 'markdown-it'
diff --git a/src/language/parser.test.ts b/src/language/parser.test.ts
index c32e47a..05c893b 100644
--- a/src/language/parser.test.ts
+++ b/src/language/parser.test.ts
@@ -1,4 +1,4 @@
-import { nextTick } from 'process'
+import { nextTick } from 'node:process'
 import dedent from 'dedent'
 import {
   Disposable,
diff --git a/src/language/parser.ts b/src/language/parser.ts
index 29ab192..c230bdd 100644
--- a/src/language/parser.ts
+++ b/src/language/parser.ts
@@ -1,4 +1,4 @@
-import { EventEmitter } from 'events'
+import { EventEmitter } from 'node:events'
 import lodashDebounce from 'lodash.debounce'
 import type TypedEmitter from 'typed-emitter'
 import {
diff --git a/src/marp-cli.test.ts b/src/marp-cli.test.ts
index 47f97b6..80e0adc 100644
--- a/src/marp-cli.test.ts
+++ b/src/marp-cli.test.ts
@@ -1,5 +1,5 @@
-import { tmpdir } from 'os'
-import path from 'path'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
 import * as marpCliModule from '@marp-team/marp-cli'
 import { workspace } from 'vscode'
 import * as marpCli from './marp-cli'
diff --git a/src/marp-cli.ts b/src/marp-cli.ts
index 20c0073..43cc4ab 100644
--- a/src/marp-cli.ts
+++ b/src/marp-cli.ts
@@ -1,5 +1,5 @@
-import { tmpdir } from 'os'
-import path from 'path'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
 import type { marpCli } from '@marp-team/marp-cli'
 import { nanoid } from 'nanoid'
 import { TextDocument, Uri, workspace } from 'vscode'
diff --git a/src/option.ts b/src/option.ts
index 2bb8d2a..4c34c04 100644
--- a/src/option.ts
+++ b/src/option.ts
@@ -1,5 +1,5 @@
-import { tmpdir } from 'os'
-import path from 'path'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
 import { MarpOptions } from '@marp-team/marp-core'
 import { Options } from 'markdown-it'
 import { nanoid } from 'nanoid'
diff --git a/src/workspace-proxy-server.ts b/src/workspace-proxy-server.ts
index f5be1ff..0b7c454 100644
--- a/src/workspace-proxy-server.ts
+++ b/src/workspace-proxy-server.ts
@@ -1,5 +1,5 @@
-import type { Server } from 'http'
-import path from 'path'
+import type { Server } from 'node:http'
+import path from 'node:path'
 import express from 'express'
 import { getPortPromise } from 'portfinder'
 import { FileType, Uri, workspace, WorkspaceFolder } from 'vscode'
diff --git a/webpack.base.config.js b/webpack.base.config.js
index 8109400..df69873 100644
--- a/webpack.base.config.js
+++ b/webpack.base.config.js
@@ -1,6 +1,7 @@
-const path = require('path')
+const path = require('node:path')
 const esbuild = require('esbuild')
 const { EsbuildPlugin } = require('esbuild-loader')
+const { NormalModuleReplacementPlugin } = require('webpack')
 
 module.exports = ({ outputPath, production, minimizerFormat }) => ({
   mode: production ? 'production' : 'none',
@@ -38,7 +39,12 @@ module.exports = ({ outputPath, production, minimizerFormat }) => ({
       }),
     ],
   },
-  plugins: [],
+  plugins: [
+    // Remove 'node:' prefix
+    new NormalModuleReplacementPlugin(/^node:/, (resource) => {
+      resource.request = resource.request.replace(/^node:/, '')
+    }),
+  ],
   performance: {
     hints: false,
   },
diff --git a/webpack.config.js b/webpack.config.js
index d1c01c1..79c858c 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -1,4 +1,4 @@
-const assert = require('assert')
+const assert = require('node:assert')
 
 const configurations = {
   node: require('./webpack.node.config'),
diff --git a/webpack.node.config.js b/webpack.node.config.js
index 37db98a..ac87200 100644
--- a/webpack.node.config.js
+++ b/webpack.node.config.js
@@ -1,4 +1,4 @@
-const path = require('path')
+const path = require('node:path')
 const pkg = require('./package.json')
 const base = require('./webpack.base.config')
 
diff --git a/webpack.preview.config.js b/webpack.preview.config.js
index c0aa093..9357b25 100644
--- a/webpack.preview.config.js
+++ b/webpack.preview.config.js
@@ -1,4 +1,4 @@
-const path = require('path')
+const path = require('node:path')
 const base = require('./webpack.base.config')
 
 const outputPath = path.resolve(__dirname, './preview/preview.js')
diff --git a/webpack.web.config.js b/webpack.web.config.js
index 63213ff..22a6e25 100644
--- a/webpack.web.config.js
+++ b/webpack.web.config.js
@@ -1,4 +1,4 @@
-const path = require('path')
+const path = require('node:path')
 const { ProvidePlugin } = require('webpack')
 const pkg = require('./package.json')
 const base = require('./webpack.base.config')