refactor(utils): simplify config port parsing in dev server detection

Let parsePortFromConfigFile return null when no port is found and apply
framework default ports in the detector layer instead.

Author: kacper-paczos

packages/utils/src/lib/dev-server/detect-dev-server-url.ts

@@ -59,7 +59,7 @@ export async function resolveDevServerUrlPrompt(
   return {
     default: detection.url,
     message:
-      detection.source != null && detection.source !== 'fallback'
+      detection.source !== 'fallback'
         ? `Target URL(s) (detected from ${detection.source}, comma-separated):`
         : 'Target URL(s) (comma-separated):',
   };

packages/utils/src/lib/dev-server/detectors.ts

@@ -168,9 +168,6 @@ const configFileDetector: DevServerDetector = {
 
     for (const file of files) {
       const filePath = path.join(targetDir, file);
-      if (!(await fileExists(filePath))) {
-        continue;
-      }
 
       for (const detector of CONFIG_FILE_DETECTORS) {
         if (!detector.pattern.test(file)) {
@@ -179,7 +176,6 @@ const configFileDetector: DevServerDetector = {
 
         const port =
           (await parsePortFromConfigFile(filePath, {
-            defaultPort: detector.defaultPort,
             sections: [...detector.sections],
           })) ?? detector.defaultPort;
 
@@ -191,7 +187,6 @@ const configFileDetector: DevServerDetector = {
       ) {
         const port =
           (await parsePortFromConfigFile(filePath, {
-            defaultPort: DEV_SERVER_PORTS.vueCli,
             sections: ['devServer'],
           })) ?? DEV_SERVER_PORTS.vueCli;
 

packages/utils/src/lib/dev-server/parse-config-port.ts

@@ -18,13 +18,7 @@ export function parseLoosePort(content: string): number | null {
 
 export async function parsePortFromConfigFile(
   filePath: string,
-  {
-    defaultPort,
-    sections = ['server', 'devServer'],
-  }: {
-    defaultPort: number;
-    sections?: string[];
-  },
+  { sections = ['server', 'devServer'] }: { sections?: string[] } = {},
 ): Promise<number | null> {
   try {
     const content = await readTextFile(filePath);
@@ -34,7 +28,7 @@ export async function parsePortFromConfigFile(
         return sectionPort;
       }
     }
-    return parseLoosePort(content) ?? defaultPort;
+    return parseLoosePort(content);
   } catch {
     return null;
   }

packages/utils/src/lib/dev-server/parse-config-port.unit.test.ts

@@ -1,4 +1,8 @@
-import { parseLoosePort, parsePortFromSection } from './parse-config-port.js';
+import {
+  parseLoosePort,
+  parsePortFromConfigFile,
+  parsePortFromSection,
+} from './parse-config-port.js';
 
 describe('parsePortFromSection', () => {
   it('should parse port from a named config section', () => {
@@ -21,4 +25,31 @@ describe('parseLoosePort', () => {
       parseLoosePort('const port = 1; export default { port: 4321 }'),
     ).toBe(4321);
   });
+
+  it('should return first port when multiple appear', () => {
+    expect(
+      parseLoosePort('const x = { port: 1234 }; const y = { port: 5678 }'),
+    ).toBe(1234);
+  });
+
+  it('should return null when no port is present', () => {
+    expect(parseLoosePort('export default {}')).toBeNull();
+  });
+});
+
+describe('parsePortFromConfigFile', () => {
+  it('should return null when file does not exist', async () => {
+    await expect(
+      parsePortFromConfigFile('/nonexistent/vite.config.ts'),
+    ).resolves.toBeNull();
+  });
+
+  it('should return null when file has no port', async () => {
+    await expect(
+      parsePortFromConfigFile(
+        new URL('./parse-config-port.unit.test.ts', import.meta.url).pathname,
+        { sections: ['server'] },
+      ),
+    ).resolves.toBeNull();
+  });
 });

packages/utils/src/lib/dev-server/types.ts

@@ -1,7 +1,7 @@
 export type DevServerDetectionResult = {
   url: string;
   port: number;
-  source: string | null;
+  source: string;
 };
 
 export type DevServerDetector = {