Conditionally generate url for import

Windows compatible

lib/esm-utils.js

@@ -1,8 +1,16 @@
 const path = require('path');
+const url = require('url');
+
+const formattedImport = async file => {
+  if (path.isAbsolute(file)) {
+    return import(url.pathToFileURL(file));
+  }
+  return import(file);
+};
 
 exports.requireOrImport = async file => {
   if (path.extname(file) === '.mjs') {
-    return import(file);
+    return formattedImport(file);
   }
   // This is currently the only known way of figuring out whether a file is CJS or ESM.
   // If Node.js or the community establish a better procedure for that, we can fix this code.
@@ -12,7 +20,7 @@ exports.requireOrImport = async file => {
     return require(file);
   } catch (err) {
     if (err.code === 'ERR_REQUIRE_ESM') {
-      return import(file);
+      return formattedImport(file);
     } else {
       throw err;
     }