chore: migrate to ESLint 9 and update configurations

.eslintignore

@@ -1,3 +0,0 @@
-dist/
-lib/
-node_modules/

.eslintrc.json

@@ -1,107 +0,0 @@
-{
-  "plugins": [
-    "@typescript-eslint"
-  ],
-  "extends": [
-    "plugin:github/typescript"
-  ],
-  "parser": "@typescript-eslint/parser",
-  "parserOptions": {
-    "ecmaVersion": 9,
-    "sourceType": "module",
-    "project": "./tsconfig.json"
-  },
-  "rules": {
-    "eslint-comments/no-use": "off",
-    "import/no-namespace": "off",
-    "no-unused-vars": "off",
-    "@typescript-eslint/explicit-member-accessibility": "off",
-    "@typescript-eslint/no-require-imports": "error",
-    "@typescript-eslint/array-type": "off",
-    "@typescript-eslint/await-thenable": "error",
-    "@typescript-eslint/ban-ts-comment": "error",
-    "camelcase": "off",
-    "@typescript-eslint/explicit-function-return-type": [
-      "error",
-      {
-        "allowExpressions": true
-      }
-    ],
-    "@typescript-eslint/func-call-spacing": [
-      "error",
-      "never"
-    ],
-    "@typescript-eslint/naming-convention": [
-      "error",
-      {
-        "selector": "default",
-        "format": [
-          "camelCase"
-        ]
-      },
-      {
-        "selector": "class",
-        "format": [
-          "PascalCase"
-        ]
-      },
-      {
-        "selector": "interface",
-        "format": [
-          "PascalCase"
-        ]
-      },
-      {
-        "selector": "typeAlias",
-        "format": [
-          "PascalCase"
-        ]
-      },
-      {
-        "selector": "property",
-        "format": null
-      },
-      {
-        "selector": "variable",
-        "format": [
-          "camelCase",
-          "UPPER_CASE"
-        ],
-        "leadingUnderscore": "allow",
-        "trailingUnderscore": "allow"
-      }
-    ],
-    "@typescript-eslint/no-array-constructor": "error",
-    "@typescript-eslint/no-empty-interface": "error",
-    "@typescript-eslint/no-explicit-any": "error",
-    "@typescript-eslint/no-extraneous-class": "error",
-    "@typescript-eslint/no-for-in-array": "error",
-    "@typescript-eslint/no-inferrable-types": "error",
-    "@typescript-eslint/no-misused-new": "error",
-    "@typescript-eslint/no-namespace": "error",
-    "@typescript-eslint/no-non-null-assertion": "warn",
-    "@typescript-eslint/no-unnecessary-qualifier": "error",
-    "@typescript-eslint/no-unnecessary-type-assertion": "error",
-    "@typescript-eslint/no-unused-vars": "off",
-    "@typescript-eslint/no-useless-constructor": "error",
-    "@typescript-eslint/no-var-requires": "error",
-    "@typescript-eslint/prefer-for-of": "warn",
-    "@typescript-eslint/prefer-function-type": "warn",
-    "@typescript-eslint/prefer-includes": "error",
-    "@typescript-eslint/prefer-string-starts-ends-with": "error",
-    "@typescript-eslint/promise-function-async": "error",
-    "@typescript-eslint/require-array-sort-compare": "error",
-    "@typescript-eslint/restrict-plus-operands": "error",
-    "semi": "off",
-    "@typescript-eslint/semi": [
-      "error",
-      "never"
-    ],
-    "@typescript-eslint/type-annotation-spacing": "error",
-    "@typescript-eslint/unbound-method": "error"
-  },
-  "env": {
-    "node": true,
-    "es6": true
-  }
-}

eslint.config.js

@@ -0,0 +1,26 @@
+import github from "eslint-plugin-github";
+
+export default [
+  github.getFlatConfigs().recommended,
+  ...github.getFlatConfigs().typescript,
+  {
+    files: ["**/*.{js,mjs,cjs,jsx,mjsx,ts,tsx,mtsx}"],
+    ignores: ["eslint.config.mjs"],
+    rules: {
+      "github/array-foreach": "error",
+      "github/async-preventdefault": "warn",
+      "github/no-then": "error",
+      "github/no-blur": "error",
+      'i18n-text/no-en': 'off',
+      'import/no-unresolved': 'off',
+      'import/no-namespace': 'off',
+    },
+    settings: {
+      'import/resolver': {
+        typescript: {
+          project: './tsconfig.json',
+        },
+      },
+    },
+  },
+];

package.json

@@ -38,12 +38,14 @@
   },
   "devDependencies": {
     "@types/node": "^20.0.0",
-    "@typescript-eslint/eslint-plugin": "^6.21.0",
-    "@typescript-eslint/parser": "^6.21.0",
+    "@typescript-eslint/eslint-plugin": "^8.31.1",
+    "@typescript-eslint/parser": "^8.31.1",
     "@vercel/ncc": "^0.38.3",
     "@vitest/coverage-v8": "^3.1.2",
-    "eslint": "^8.57.1",
-    "eslint-plugin-github": "^4.10.2",
+    "eslint": "^9.26.0",
+    "eslint-define-config": "^2.1.0",
+    "eslint-import-resolver-typescript": "^4.3.4",
+    "eslint-plugin-github": "^6.0.0",
     "js-yaml": "^4.0.0",
     "prettier": "^3.5.3",
     "typescript": "^5.8.3",

src/issue.ts

@@ -2,8 +2,8 @@ import * as core from '@actions/core'
 import {IssueOption} from './interface.js'
 
 export function getIssueOption(body: string): IssueOption {
-  let assignees
-  let labels
+  let assignees: string[] | undefined
+  let labels: string[] | undefined
 
   if (core.getInput('issue_assignees')) {
     assignees = core.getInput('issue_assignees').replace(/\s+/g, '').split(',')
@@ -29,7 +29,7 @@ export type GetIssuesFunc = (options: {
   state: 'open' | 'closed' | 'all' | undefined
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   [key: string]: any // Allow additional properties
-}) => Promise<{data: {title: string; number: number}[]}>
+}) => Promise<{data: Array<{title: string; number: number}>}>
 
 export async function getExistingIssueNumber(
   getIssues: GetIssuesFunc,

tsconfig.json

@@ -6,7 +6,11 @@
     "rootDir": "./src", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
     "strict": true, /* Enable all strict type-checking options. */
     "noImplicitAny": true, /* Raise error on expressions and declarations with an implied 'any' type. */
-    "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    "esModuleInterop": true, /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    "baseUrl": "./",
+    "paths": {
+      "*": ["src/*"]
+    }
   },
   "exclude": [
     "node_modules",