esm: align sync and async load implementations

Refs: #48272
PR-URL: #49152
Refs: #47999
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Jacob Smith <jacob@frende.me>

lib/internal/modules/esm/load.js

@@ -70,25 +70,30 @@ async function getSource(url, context) {
   return { __proto__: null, responseURL, source };
 }
 
+/**
+ * @param {URL} url URL to the module
+ * @param {ESModuleContext} context used to decorate error messages
+ * @returns {{ responseURL: string, source: string | BufferView }}
+ */
 function getSourceSync(url, context) {
-  const parsed = new URL(url);
-  const responseURL = url;
+  const { protocol, href } = url;
+  const responseURL = href;
   let source;
-  if (parsed.protocol === 'file:') {
-    source = readFileSync(parsed);
-  } else if (parsed.protocol === 'data:') {
-    const match = RegExpPrototypeExec(DATA_URL_PATTERN, parsed.pathname);
+  if (protocol === 'file:') {
+    source = readFileSync(url);
+  } else if (protocol === 'data:') {
+    const match = RegExpPrototypeExec(DATA_URL_PATTERN, url.pathname);
     if (!match) {
-      throw new ERR_INVALID_URL(url);
+      throw new ERR_INVALID_URL(responseURL);
     }
     const { 1: base64, 2: body } = match;
     source = BufferFrom(decodeURIComponent(body), base64 ? 'base64' : 'utf8');
   } else {
     const supportedSchemes = ['file', 'data'];
-    throw new ERR_UNSUPPORTED_ESM_URL_SCHEME(parsed, supportedSchemes);
+    throw new ERR_UNSUPPORTED_ESM_URL_SCHEME(url, supportedSchemes);
   }
   if (policy?.manifest) {
-    policy.manifest.assertIntegrity(parsed, source);
+    policy.manifest.assertIntegrity(url, source);
   }
   return { __proto__: null, responseURL, source };
 }
@@ -159,14 +164,18 @@ function defaultLoadSync(url, context = kEmptyObject) {
     source,
   } = context;
 
-  format ??= defaultGetFormat(new URL(url), context);
+  const urlInstance = new URL(url);
+
+  throwIfUnsupportedURLScheme(urlInstance, false);
+
+  format ??= defaultGetFormat(urlInstance, context);
 
   validateAssertions(url, format, importAssertions);
 
   if (format === 'builtin') {
     source = null;
   } else if (source == null) {
-    ({ responseURL, source } = getSourceSync(url, context));
+    ({ responseURL, source } = getSourceSync(urlInstance, context));
   }
 
   return {