Apply suggestions from code review

Co-authored-by: Titus <tituswormer@gmail.com>

lib/server.js

@@ -33,9 +33,10 @@ function filterHeaders(allowedHeaders) {
     const filteredHeaders = {}
 
     for (const [key, bool] of allowedHeaders.entries()) {
-      if (incomingHeaders.has(key.toLowerCase()) && bool) {
-        // @ts-ignore
-        filteredHeaders[key] = incomingHeaders.get(key.toLowerCase())
+      const value = incomingHeaders.get(key.toLowerCase())
+
+      if (value !== null && value !== undefined && bool) {
+        filteredHeaders[key] = value
       }
     }
 
@@ -79,8 +80,7 @@ export class Server extends EventEmitter {
       return this.write(res, 405, 'Method not allowed')
     }
 
-    // @ts-ignore req.url is fine
-    const paths = url.parse(req.url)?.path?.split('/')
+    const paths = url.parse(req.url || '')?.path?.split('/')
 
     if (!paths || paths.length < 3) {
       return this.write(res, 404, 'Malformed request')
@@ -96,8 +96,8 @@ export class Server extends EventEmitter {
     try {
       var validUrl = await SafeHttpClient.checkUrl(decodedUrl)
     } catch (err) {
-      // @ts-ignore err does have message
-      return this.write(res, 400, err.message)
+      const exception = /** @type {Error} */ (err)
+      return this.write(res, 400, exception.message)
     }
 
     const controller = new AbortController()