eslint.config.js

// ESLint flat config for TypeScript/JavaScript
// https://eslint.org/docs/latest/use/configure/configuration-files

import { defineConfig } from "eslint/config";
import js from "@eslint/js";
import tseslint from "typescript-eslint";
import prettierConfig from "eslint-config-prettier";

export default defineConfig(
  // Global ignores
  {
    ignores: [
      "node_modules/**",
      "internal/web/static/js/*.js", // Generated/minified JS
      "internal/web/static/styles.css", // Generated CSS
      "vendor/**",
      "dist/**",
      "coverage/**",
      "*.min.js"
    ]
  },

  // Base JavaScript configuration for all JS/MJS/CJS files
  {
    files: ["**/*.js", "**/*.cjs", "**/*.mjs"],
    ...js.configs.recommended,
    rules: {
      "no-console": "off" // Config files can use console
    }
  },

  // TypeScript strict type-checked configuration (only for TS files)
  {
    files: ["**/*.ts", "**/*.tsx"],
    extends: [tseslint.configs.strictTypeChecked, tseslint.configs.stylisticTypeChecked]
  },

  // Project-specific TypeScript settings
  {
    files: ["**/*.ts", "**/*.tsx"],
    languageOptions: {
      parserOptions: {
        projectService: true,
        tsconfigRootDir: import.meta.dirname
      }
    },
    rules: {
      // TypeScript-specific rules
      "@typescript-eslint/no-unused-vars": [
        "error",
        {
          argsIgnorePattern: "^_",
          varsIgnorePattern: "^_",
          caughtErrorsIgnorePattern: "^_"
        }
      ],
      "@typescript-eslint/explicit-function-return-type": "off",
      "@typescript-eslint/explicit-module-boundary-types": "off",
      "@typescript-eslint/no-explicit-any": "error",
      "@typescript-eslint/no-non-null-assertion": "error",
      "@typescript-eslint/no-unnecessary-condition": "error",
      "@typescript-eslint/prefer-nullish-coalescing": "error",
      "@typescript-eslint/prefer-optional-chain": "error",
      "@typescript-eslint/consistent-type-imports": [
        "error",
        {
          prefer: "type-imports",
          fixStyle: "inline-type-imports"
        }
      ],

      // General best practices
      "no-console": ["warn", { allow: ["warn", "error"] }],
      "no-debugger": "error",
      "no-alert": "warn",
      "prefer-const": "error",
      "no-var": "error",
      eqeqeq: ["error", "always", { null: "ignore" }],
      curly: ["error", "all"],
      "no-eval": "error",
      "no-implied-eval": "error",
      "no-script-url": "error",
      "no-with": "error",

      // Security
      "no-unsafe-negation": "error",
      "no-unsafe-optional-chaining": "error"
    }
  },

  // Prettier compatibility (must be last)
  prettierConfig
);