chore: update ESLint to v9 and switch to flat config

eslint.config.mjs

@@ -0,0 +1,52 @@
+import js from '@eslint/js';
+import globals from 'globals';
+
+/** @type {import('eslint').Linter.FlatConfig[]} */
+export default [
+  // global ignores
+  {
+    ignores: [
+      '.yarn/**',
+      'node_modules/**',
+      'dist/**',
+      'test/regression-fixtures/**',
+      'test/regression-diffs/**',
+      'test/cli/output/**',
+      'coverage/**',
+    ],
+  },
+  {
+    languageOptions: {
+      ecmaVersion: 2021,
+      sourceType: 'module',
+      globals: {
+        ...globals.nodeBuiltin,
+      },
+    },
+    linterOptions: {
+      reportUnusedDisableDirectives: 'error',
+    },
+  },
+  js.configs.recommended,
+  {
+    files: ['**/*.js', '**/*.mjs'],
+    rules: {
+      strict: 'error',
+    },
+  },
+  {
+    files: ['**/*.cjs'],
+    languageOptions: {
+      sourceType: 'commonjs',
+    },
+  },
+  {
+    files: ['**/*.test.js'],
+    languageOptions: {
+      sourceType: 'module',
+      globals: {
+        ...globals.jest,
+      },
+    },
+  },
+];

lib/svgo-node.js

@@ -34,7 +34,7 @@ export const loadConfig = async (configFile, cwd = process.cwd()) => {
     }
   }
   let dir = cwd;
-  // eslint-disable-next-line no-constant-condition
+
   while (true) {
     const js = path.join(dir, 'svgo.config.js');
     if (await isFile(js)) {

lib/svgo/coa.js

@@ -20,7 +20,7 @@ const regSVGFile = /\.svg$/i;
 export function checkIsDir(filePath) {
   try {
     return fs.lstatSync(filePath).isDirectory();
-  } catch (e) {
+  } catch {
     return filePath.endsWith(path.sep);
   }
 }

package.json

@@ -86,8 +86,8 @@
   },
   "scripts": {
     "test": "NODE_OPTIONS=--experimental-vm-modules jest --maxWorkers=4 --coverage",
-    "lint": "eslint --ignore-path .gitignore . && prettier --check . --ignore-path .gitignore",
-    "fix": "eslint --ignore-path .gitignore --fix . && prettier --write . --ignore-path .gitignore",
+    "lint": "eslint . && prettier --check . --ignore-path .gitignore",
+    "fix": "eslint --fix . && prettier --write . --ignore-path .gitignore",
     "typecheck": "tsc",
     "generate-bundles": "rollup -c",
     "test-bundles": "yarn generate-bundles && node ./test/svgo.cjs && node ./test/browser.js",
@@ -110,14 +110,16 @@
     "picocolors": "^1.0.0"
   },
   "devDependencies": {
+    "@eslint/js": "^9.2.0",
     "@rollup/plugin-commonjs": "^25.0.7",
     "@rollup/plugin-node-resolve": "^15.2.3",
     "@rollup/plugin-terser": "^0.4.4",
     "@types/css-tree": "^2.3.7",
     "@types/csso": "^5.0.4",
     "@types/jest": "^29.5.12",
     "@types/node": "^20.12.11",
-    "eslint": "^8.57.0",
+    "eslint": "^9.2.0",
+    "globals": "^14.0.0",
     "jest": "^29.7.0",
     "node-fetch": "^2.7.0",
     "pixelmatch": "^5.3.0",

plugins/_path.js

@@ -262,7 +262,7 @@ export const intersects = function (path1, path2) {
         direction = minus(simplex[0]); // set the direction to point towards the origin
 
       var iterations = 1e4; // infinite loop protection, 10 000 iterations is more than enough
-      // eslint-disable-next-line no-constant-condition
+
       while (true) {
         if (iterations-- == 0) {
           console.error(

plugins/inlineStyles.js

@@ -190,7 +190,7 @@ export const fn = (root, params) => {
                 matchedElements.push(node);
               }
             }
-          } catch (selectError) {
+          } catch {
             continue;
           }
           // nothing selected

test/regression.js

@@ -105,7 +105,7 @@ const runTests = async (list) => {
       let file;
       try {
         file = await fs.readFile(path.join(fixturesDir, name), 'utf-8');
-      } catch (error) {
+      } catch {
         res.statusCode = 404;
         res.end();
         return;