Support TypeScript 5 (#712)

.gitignore

@@ -6,5 +6,7 @@ test/fixtures/project/node_modules/.cache
 test/fixtures/typescript/extends-module/node_modules/.cache
 !test/fixtures/typescript/extends-tsconfig-bases/node_modules
 test/fixtures/typescript/extends-tsconfig-bases/node_modules/.cache
+!test/fixtures/typescript/extends-array/node_modules
+test/fixtures/typescript/extends-array/node_modules/.cache
 .nyc_output
 coverage

lib/options-manager.js

@@ -2,7 +2,6 @@ import {existsSync, promises as fs} from 'node:fs';
 import process from 'node:process';
 import os from 'node:os';
 import path from 'node:path';
-import {createRequire} from 'node:module';
 import arrify from 'arrify';
 import {mergeWith, flow, pick} from 'lodash-es';
 import {findUpSync} from 'find-up';
@@ -11,12 +10,12 @@ import prettier from 'prettier';
 import semver from 'semver';
 import {cosmiconfig, defaultLoaders} from 'cosmiconfig';
 import micromatch from 'micromatch';
-import JSON5 from 'json5';
 import stringify from 'json-stable-stringify-without-jsonify';
 import {Legacy} from '@eslint/eslintrc';
 import createEsmUtils from 'esm-utils';
 import MurmurHash3 from 'imurmurhash';
 import slash from 'slash';
+import {getTsconfig} from 'get-tsconfig';
 import {
 	DEFAULT_IGNORES,
 	DEFAULT_EXTENSION,
@@ -159,26 +158,20 @@ const handleTSConfig = async options => {
 	options.tsConfig = {};
 	options.tsConfigPath = '';
 
-	const {project: tsConfigProjectPath, tsconfigRootDir} = options.parserOptions || {};
+	const {project: tsConfigProjectPath} = options.parserOptions || {};
 
 	if (tsConfigProjectPath) {
 		options.tsConfigPath = path.resolve(options.cwd, tsConfigProjectPath);
-		options.tsConfig = JSON5.parse(await fs.readFile(options.tsConfigPath));
+		options.tsConfig = tsConfigResolvePaths(getTsconfig(options.tsConfigPath).config, options.tsConfigPath);
 	} else {
-		const tsConfigExplorer = cosmiconfig([], {
-			searchPlaces: ['tsconfig.json'],
-			loaders: {'.json': (_, content) => JSON5.parse(content)},
-			stopDir: tsconfigRootDir,
-		});
-		const searchResults = (await tsConfigExplorer.search(options.filePath)) || {};
-		options.tsConfigPath = searchResults.filepath;
-		options.tsConfig = searchResults.config;
-	}
-
-	if (options.tsConfig) {
-		// If the tsconfig extends from another file, we need to ensure that the file is covered by the tsconfig
-		// or not. The basefile could have includes/excludes/files properties that should be applied to the final tsconfig representation.
-		options.tsConfig = await recursiveBuildTsConfig(options.tsConfig, options.tsConfigPath);
+		const {config: tsConfig, path: filepath} = getTsconfig(options.filePath) || {};
+		options.tsConfigPath = filepath;
+		options.tsConfig = tsConfig;
+		if (options.tsConfigPath) {
+			options.tsConfig = tsConfigResolvePaths(tsConfig, options.tsConfigPath);
+		} else {
+			delete options.tsConfig;
+		}
 	}
 
 	let hasMatch;
@@ -637,46 +630,6 @@ const getOptionGroups = async (files, options) => {
 	return optionGroups;
 };
 
-async function recursiveBuildTsConfig(tsConfig, tsConfigPath) {
-	tsConfig = tsConfigResolvePaths(tsConfig, tsConfigPath);
-
-	if (!tsConfig.extends || (typeof tsConfig.extends === 'string' && tsConfig.extends.includes('node_modules'))) {
-		return tsConfig;
-	}
-
-	// If any of the following are missing, then we need to look up the base config as it could apply
-	const require = createRequire(tsConfigPath);
-
-	let basePath;
-	try {
-		basePath = require.resolve(tsConfig.extends);
-	} catch (error) {
-		// Tsconfig resolution is odd, It allows behavior that is not exactly like node resolution
-		// therefore we attempt to smooth this out here with this hack
-		try {
-			basePath = require.resolve(path.join(tsConfig.extends, 'tsconfig.json'));
-		} catch {
-			// Throw the orginal resolution error to let the user know their extends block is invalid
-			throw error;
-		}
-	}
-
-	const baseTsConfig = JSON5.parse(await fs.readFile(basePath));
-
-	delete tsConfig.extends;
-
-	tsConfig = {
-		compilerOptions: {
-			...baseTsConfig.compilerOptions,
-			...tsConfig.compilerOptions,
-		},
-		...baseTsConfig,
-		...tsConfig,
-	};
-
-	return recursiveBuildTsConfig(tsConfig, basePath);
-}
-
 // Convert all include, files, and exclude to absolute paths
 // and or globs. This works because ts only allows simple glob subset
 const tsConfigResolvePaths = (tsConfig, tsConfigPath) => {

package.json

@@ -81,10 +81,10 @@
 		"find-cache-dir": "^4.0.0",
 		"find-up": "^6.3.0",
 		"get-stdin": "^9.0.0",
+		"get-tsconfig": "^4.5.0",
 		"globby": "^13.1.2",
 		"imurmurhash": "^0.1.4",
 		"json-stable-stringify-without-jsonify": "^1.0.1",
-		"json5": "^2.2.1",
 		"lodash-es": "^4.17.21",
 		"meow": "^11.0.0",
 		"micromatch": "^4.0.5",
@@ -93,7 +93,7 @@
 		"semver": "^7.3.8",
 		"slash": "^5.0.0",
 		"to-absolute-glob": "^2.0.2",
-		"typescript": "^4.9.3"
+		"typescript": "^5.0.3"
 	},
 	"devDependencies": {
 		"ava": "^5.1.0",

test/fixtures/typescript/extends-array/package.json

@@ -0,0 +1,3 @@
+{
+	"xo": {}
+}

test/fixtures/typescript/extends-array/tsconfig.json

@@ -0,0 +1,6 @@
+{
+	"extends": [
+		"@sindresorhus/tsconfig",
+		"@tsconfig/node16"
+	],
+}

test/options-manager.js

@@ -691,6 +691,15 @@ test('mergeWithFileConfig: tsconfig can properly extend tsconfig base node_modul
 	t.is(options.tsConfigPath, expectedConfigPath);
 });
 
+test('mergeWithFileConfig: tsconfig can properly resolve extends arrays introduced in ts 5', async t => {
+	const cwd = path.resolve('fixtures', 'typescript', 'extends-array');
+	const expectedConfigPath = path.join(cwd, 'tsconfig.json');
+	const filePath = path.resolve(cwd, 'does-not-matter.ts');
+	await t.notThrowsAsync(manager.mergeWithFileConfig({cwd, filePath}));
+	const {options} = await manager.mergeWithFileConfig({cwd, filePath});
+	t.is(options.tsConfigPath, expectedConfigPath);
+});
+
 test('applyOverrides', t => {
 	t.deepEqual(
 		manager.applyOverrides(