Use eslint-config-pa11y for linting (#342)

* Use ESLint 9 and `eslint-config-pa11y`; rename config

* Ignore `public/js`, loosen rules for tests

* Allow free `max-len` in `data/*`

* Destructure more

* Fix whitespace and trailing commas

* Allow `fetch` in tests

* Use `path.join` instead of plain strings

* Remove obsolete `.eslintignore`

Author: danyalaytekin

.eslintignore

@@ -23,6 +23,7 @@ const hbs = require('express-hbs');
 const morgan = require('morgan');
 const {nanoid} = require('nanoid');
 const http = require('http');
+const path = require('path');
 const pkg = require('./package.json');
 
 module.exports = initApp;
@@ -85,7 +86,7 @@ function loadMiddleware(app) {
 	app.express.use(morgan(endLog));
 
 	// Public files
-	app.express.use(express.static(`${__dirname}/public`, {
+	app.express.use(express.static(path.join(__dirname, 'public'), {
 		maxAge: (process.env.NODE_ENV === 'production' ? 604800000 : 0)
 	}));
 
@@ -100,11 +101,11 @@ function loadViewEngine(app, config) {
 	app.express.engine('html', hbs.express4({
 		extname: '.html',
 		contentHelperName: 'content',
-		layoutsDir: `${__dirname}/view/layout`,
-		partialsDir: `${__dirname}/view/partial`,
-		defaultLayout: `${__dirname}/view/layout/default`
+		layoutsDir: path.join(__dirname, 'view', 'layout'),
+		partialsDir: path.join(__dirname, 'view', 'partial'),
+		defaultLayout: path.join(__dirname, 'view', 'layout', 'default')
 	}));
-	app.express.set('views', `${__dirname}/view`);
+	app.express.set('views', path.join(__dirname, 'view'));
 	app.express.set('view engine', 'html');
 
 	// View helpers

.eslintrc.js

@@ -0,0 +1,30 @@
+'use strict';
+
+const {defineConfig} = require('eslint/config');
+
+const configPa11y = require('eslint-config-pa11y');
+
+module.exports = defineConfig([
+	configPa11y,
+	{
+		ignores: [
+			'public/js/*'
+		]
+	},
+	{
+		files: ['test/**/*.js', 'test/**/*.cjs'],
+		rules: {
+			'prefer-arrow-callback': 'off',
+			'no-invalid-this': 'off',
+			'n/no-unsupported-features/node-builtins': ['error', {
+				ignores: ['fetch']
+			}]
+		}
+	},
+	{
+		files: ['data/*'],
+		rules: {
+			'max-len': 'off'
+		}
+	}
+]);