fix: URL constructor throws confusing error on invalid scheme (#5057)

2 files changed, 11 insertions, 3 deletions

diff --git a/cli/js/tests/url_test.ts b/cli/js/tests/url_test.ts
index 12e7cb26a..6529bf055 100644
--- a/cli/js/tests/url_test.ts
+++ b/cli/js/tests/url_test.ts
@@ -224,7 +224,7 @@ unitTest(function throwForInvalidPortConstructor(): void {
   ];
 
   for (const url of urls) {
-    assertThrows(() => new URL(url));
+    assertThrows(() => new URL(url), TypeError, "Invalid URL.");
   }
 
   // Do not throw for 0 & 65535
@@ -232,6 +232,14 @@ unitTest(function throwForInvalidPortConstructor(): void {
   new URL("https://baz.qat:0");
 });
 
+unitTest(function throwForInvalidSchemeConstructor(): void {
+  assertThrows(
+    () => new URL("invalid_scheme://baz.qat"),
+    TypeError,
+    "Invalid URL."
+  );
+});
+
 unitTest(function doNotOverridePortIfInvalid(): void {
   const initialPort = "3000";
   const ports = [
diff --git a/cli/js/web/url.ts b/cli/js/web/url.ts
index 1ae24ff87..cdbba36d9 100644
--- a/cli/js/web/url.ts
+++ b/cli/js/web/url.ts
@@ -370,7 +370,7 @@ export class URLImpl implements URL {
       throw new TypeError("Invalid URL.");
     }
 
-    const { port } = (urlParts.protocol ? urlParts : baseParts) as URLParts;
+    const { port } = !urlParts.protocol && baseParts ? baseParts : urlParts;
     if (this.#validatePort(port) === undefined) {
       throw new TypeError("Invalid URL.");
     }
@@ -389,7 +389,7 @@ export class URLImpl implements URL {
         hash: urlParts.hash,
       });
     } else {
-      throw new TypeError("URL requires a base URL.");
+      throw new TypeError("Invalid URL.");
     }
 
     this.#updateSearchParams();