`eslint.config.mjs`

64 lines
// Flat ESLint config — DEV-ONLY static analysis for the photo-capture tool.
// Goal: catch correctness bugs (undefined vars like the getLS crash, typos,
// unreachable code) as ERRORS, while keeping pure-style nits as warnings so
// the signal isn't drowned in noise. Nothing here ships or is required at runtime.
import js from "@eslint/js";
import globals from "globals";
import html from "eslint-plugin-html";

// Rules we hold as hard errors — the bug classes that actually break the app.
const correctness = {
  "no-undef": "error",            // <- this is the rule that catches `getLS`
  "no-unreachable": "error",
  "no-dupe-keys": "error",
  "no-dupe-args": "error",
  "no-func-assign": "error",
  "no-cond-assign": ["error", "always"],
  "no-constant-condition": ["error", { checkLoops: false }],
  "use-isnan": "error",
  "valid-typeof": "error",
};

// Style / hygiene — surfaced but non-blocking.
// caughtErrors:"none" silences idiomatic throwaway `catch (e) {}` bindings so the
// only no-unused-vars hits left are GENUINE dead variables (real refactor targets).
const hygiene = {
  "no-unused-vars": ["warn", { args: "none", caughtErrors: "none", varsIgnorePattern: "^_" }],
  "no-empty": ["warn", { allowEmptyCatch: true }],
};

export default [
  js.configs.recommended,

  // Server-side: Node CommonJS.
  {
    files: ["server.js", "**/*.cjs", "test-*.js"],
    languageOptions: {
      ecmaVersion: 2022,
      sourceType: "commonjs",
      globals: { ...globals.node },
    },
    rules: { ...correctness, ...hygiene },
  },

  // selfcheck-ui.cjs is a Node script, but the strings it passes to Playwright's
  // page.$eval() execute in the BROWSER — so it legitimately references browser
  // globals (getComputedStyle, document, …). Give it both worlds.
  {
    files: ["selfcheck-ui.cjs"],
    languageOptions: { globals: { ...globals.node, ...globals.browser } },
  },

  // Front-end: the <script> block extracted from index.html, browser globals.
  {
    files: ["public/**/*.html"],
    plugins: { html },
    languageOptions: {
      ecmaVersion: 2022,
      sourceType: "script",
      globals: { ...globals.browser },
    },
    rules: { ...correctness, ...hygiene },
  },
];