Update to ESLint 10 and align with sitespeed.io's ESLint stack

eslint.config.cjs

@@ -1,19 +1,12 @@
 const prettier = require('eslint-plugin-prettier');
 const globals = require('globals');
 const js = require('@eslint/js');
-const { FlatCompat } = require('@eslint/eslintrc');
-
-const compat = new FlatCompat({
-  baseDirectory: __dirname,
-  recommendedConfig: js.configs.recommended,
-  allConfig: js.configs.all
-});
 
 module.exports = [
   {
     ignores: ['**/dist/', '**/node_modules/', '**/test/', '**/tools/']
   },
-  ...compat.extends('eslint:recommended'),
+  js.configs.recommended,
   {
     plugins: {
       prettier

lib/dom/performance/firstContentfulPaint.js

@@ -1,7 +1,7 @@
 (function (util) {
   'use strict';
   let score = 100;
-  let advice = '';
+  let advice;
   const good = 1800;
   const needImprovement = 3000;
 

lib/dom/performance/interactionToNextPaint.js

@@ -14,7 +14,7 @@
   //   needs improvement   200–500 ms
   //   poor                > 500 ms
   let score = 100;
-  let advice = '';
+  let advice;
   const offending = [];
   const good = 200;
   const needImprovement = 500;

lib/har/performance/avoidRenderBlocking.js

@@ -20,7 +20,6 @@ export default {
     ) {
       if (page.renderBlocking && Object.keys(page.renderBlocking).length > 0) {
         // we use Chrome(ium) and have render blocking info
-        advice = '';
         for (let asset of page.assets) {
           if (
             (asset.renderBlocking && asset.renderBlocking === 'blocking') ||

lib/har/privacy/thirdPartyPrivacy.js

@@ -25,7 +25,7 @@ export default {
         : 0;
 
     let score = 100 - Math.round(thirdPartyPercent);
-    let advice = '';
+    let advice;
     if (thirdPartyPercent === 100) {
       advice =
         'The page has 100% of third party requests! Something is probably wrong? Verify that you test the right page.';

lib/technologies/wappalyzer.js

@@ -357,7 +357,7 @@ export function analyze(items, technologies = state.technologies) {
       .flat()
       .filter((t) => t);
   } catch (error) {
-    throw new Error(error.message || error.toString());
+    throw new Error(error.message || error.toString(), { cause: error });
   }
 }
 
@@ -380,7 +380,7 @@ function resolveExcludes(resolved) {
 }
 
 function resolveImplies(resolved) {
-  let done = false;
+  let done;
   do {
     done = true;
     resolved.forEach(({ technology, confidence, lastUrl }) => {