module: reduce url invocations in esm/load.js

PR-URL: nodejs#48337
Refs: nodejs/performance#92
Reviewed-By: Stephen Belanger <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: Geoffrey Booth <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Jacob Smith <[email protected]>

Author: anonrig

lib/internal/modules/esm/load.js

@@ -29,37 +29,42 @@ const {
 
 const DATA_URL_PATTERN = /^[^/]+\/[^,;]+(?:[^,]*?)(;base64)?,([\s\S]*)$/;
 
+/**
+ * @param {URL} url URL to the module
+ * @param {ESModuleContext} context used to decorate error messages
+ * @returns {{ responseURL: string, source: string | BufferView }}
+ */
 async function getSource(url, context) {
-  const parsed = new URL(url);
-  let responseURL = url;
+  const { protocol, href } = url;
+  let responseURL = href;
   let source;
-  if (parsed.protocol === 'file:') {
+  if (protocol === 'file:') {
     const { readFile: readFileAsync } = require('internal/fs/promises').exports;
-    source = await readFileAsync(parsed);
-  } else if (parsed.protocol === 'data:') {
-    const match = RegExpPrototypeExec(DATA_URL_PATTERN, parsed.pathname);
+    source = await readFileAsync(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 if (experimentalNetworkImports && (
-    parsed.protocol === 'https:' ||
-    parsed.protocol === 'http:'
+    protocol === 'https:' ||
+    protocol === 'http:'
   )) {
     const { fetchModule } = require('internal/modules/esm/fetch_module');
-    const res = await fetchModule(parsed, context);
+    const res = await fetchModule(url, context);
     source = await res.body;
     responseURL = res.resolvedHREF;
   } else {
     const supportedSchemes = ['file', 'data'];
     if (experimentalNetworkImports) {
       ArrayPrototypePush(supportedSchemes, 'http', 'https');
     }
-    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(href, source);
   }
   return { __proto__: null, responseURL, source };
 }
@@ -93,7 +98,7 @@ async function defaultLoad(url, context = kEmptyObject) {
   ) {
     source = null;
   } else if (source == null) {
-    ({ responseURL, source } = await getSource(url, context));
+    ({ responseURL, source } = await getSource(urlInstance, context));
   }
 
   return {