chore(cli): improve typescript detection (#710)

Co-authored-by: Manuel <30698007+manuel3108@users.noreply.github.com>

Author: jycouet

.changeset/orange-rules-hug.md

@@ -0,0 +1,5 @@
+---
+"sv": patch
+---
+
+chore(cli): improve `typescript` detection

packages/cli/commands/add/utils.ts

@@ -110,6 +110,7 @@ export function fileExists(cwd: string, filePath: string): boolean {
 export const commonFilePaths = {
 	packageJson: 'package.json',
 	svelteConfig: 'svelte.config.js',
+	jsconfig: 'jsconfig.json',
 	tsconfig: 'tsconfig.json',
 	viteConfig: 'vite.config.js',
 	viteConfigTS: 'vite.config.ts'

packages/cli/commands/add/workspace.ts

@@ -5,7 +5,6 @@ import { common, object, type AstTypes } from '@sveltejs/cli-core/js';
 import { parseScript } from '@sveltejs/cli-core/parsers';
 import { detect } from 'package-manager-detector';
 import type { OptionValues, PackageManager, Workspace } from '@sveltejs/cli-core';
-import { TESTING } from '../../utils/env.ts';
 import { commonFilePaths, getPackageJson, readFile } from './utils.ts';
 import { getUserAgent } from '../../utils/package-manager.ts';
 
@@ -20,18 +19,17 @@ export async function createWorkspace({
 	packageManager
 }: CreateWorkspaceOptions): Promise<Workspace<any>> {
 	const resolvedCwd = path.resolve(cwd);
-	const viteConfigPath = path.join(resolvedCwd, commonFilePaths.viteConfigTS);
-	let usesTypescript = fs.existsSync(viteConfigPath);
 
-	const viteConfigFile = usesTypescript ? commonFilePaths.viteConfigTS : commonFilePaths.viteConfig;
+	// Will go up and prioritize jsconfig.json as it's first in the array
+	const tjsconfig = find.any([commonFilePaths.jsconfig, commonFilePaths.tsconfig], { cwd });
+	// If the file is not ending with jsconfig.json, then we are using typescript
+	const usesTypescript = !tjsconfig?.endsWith(commonFilePaths.jsconfig);
 
-	if (TESTING) {
-		// while executing tests, we only look into the direct `cwd`
-		// as we might detect the monorepo `tsconfig.json` otherwise.
-		usesTypescript ||= fs.existsSync(path.join(resolvedCwd, commonFilePaths.tsconfig));
-	} else {
-		usesTypescript ||= find.up(commonFilePaths.tsconfig, { cwd }) !== undefined;
-	}
+	// This is not linked with typescript detection
+	const viteConfigPath = path.join(resolvedCwd, commonFilePaths.viteConfigTS);
+	const viteConfigFile = fs.existsSync(viteConfigPath)
+		? commonFilePaths.viteConfigTS
+		: commonFilePaths.viteConfig;
 
 	let dependencies: Record<string, string> = {};
 	let directory = resolvedCwd;