module: be lazy when creating CJS facades

This should remove the penalty for loading CJS that is never imported. PR-URL: nodejs#17153 Reviewed-By: Jeremiah Senkpiel <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Timothy Gu <[email protected]> Reviewed-By: James M Snell <[email protected]>
thw0rted · Nov 28, 2017 · 2219859 · 2219859
1 parent b44efde
commit 2219859
Showing 1 changed file with 11 additions and 5 deletions.
diff --git a/lib/module.js b/lib/module.js
@@ -575,15 +575,21 @@ Module.prototype.load = function(filename) {
   if (ESMLoader) {
     const url = getURLFromFilePath(filename);
     const urlString = `${url}`;
+    const exports = this.exports;
     if (ESMLoader.moduleMap.has(urlString) !== true) {
-      const ctx = createDynamicModule(['default'], url);
-      ctx.reflect.exports.default.set(this.exports);
-      ESMLoader.moduleMap.set(urlString,
-                              new ModuleJob(ESMLoader, url, async () => ctx));
+      ESMLoader.moduleMap.set(
+        urlString,
+        new ModuleJob(ESMLoader, url, async () => {
+          const ctx = createDynamicModule(
+            ['default'], url);
+          ctx.reflect.exports.default.set(exports);
+          return ctx;
+        })
+      );
     } else {
       const job = ESMLoader.moduleMap.get(urlString);
       if (job.reflect)
-        job.reflect.exports.default.set(this.exports);
+        job.reflect.exports.default.set(exports);
     }
   }
 };