feat: upgrade ESLint to version 9 (#1558)

eslint.config.js

@@ -0,0 +1,66 @@
+// eslint.config.js
+
+import { defineConfig } from 'eslint-define-config';
+import ts from '@typescript-eslint/parser';
+import tsEslint from '@typescript-eslint/eslint-plugin';
+import stylisticEslint from '@stylistic/eslint-plugin';
+
+export default defineConfig([
+	{
+		ignores: ['**/*.test.js'],
+	},
+	{
+		files: ['**/*.ts', '**/*.tsx'],
+		languageOptions: {
+			parser: ts,
+			parserOptions: {
+				ecmaVersion: 2024,
+				sourceType: 'module',
+				project: './tsconfig.json',
+				ecmaFeatures: {
+					impliedStrict: true,
+				},
+			},
+			globals: {
+				// declare global variables here
+				browser: 'readonly',
+				es2024: true,
+				mocha: 'readonly',
+			},
+		},
+		plugins: {
+			'@typescript-eslint': tsEslint,
+			'@stylistic': stylisticEslint,
+		},
+		rules: {
+			'@typescript-eslint/no-var-requires': 'off', // allows require statements outside of imports
+			'@typescript-eslint/no-floating-promises': 'warn',
+			'no-unused-expressions': 'off',
+			'@typescript-eslint/no-unused-expressions': 'off',
+			'@typescript-eslint/no-unused-vars': [
+				'warn',
+				{
+					vars: 'all',
+					args: 'after-used',
+					ignoreRestSiblings: true,
+					caughtErrors: 'none', // ignore unused variables in catch blocks
+				},
+			],
+			'@typescript-eslint/no-namespace': 'off',
+			'@typescript-eslint/no-explicit-any': 'off',
+			'@typescript-eslint/no-this-alias': 'off',
+			'@typescript-eslint/naming-convention': [
+				'error',
+				{
+					selector: 'variable',
+					format: ['camelCase', 'PascalCase', 'UPPER_CASE'],
+				},
+			],
+			'@stylistic/semi': 'warn',
+			curly: 'warn',
+			eqeqeq: ['warn', 'always'],
+			'no-redeclare': 'warn',
+			'no-throw-literal': 'warn',
+		},
+	},
+]);