Refactoring files.ts to reduce nesting

src/files.ts

@@ -13,43 +13,55 @@ import { Statement } from 'meriyah/dist/src/estree';
  *
  * @returns {string} absolute path or an empty string if no caller
  */
-export const getCallerFilePath = (): string => {
+export const getCallerDirname = (): string => {
   const orig = Error.prepareStackTrace;
   Error.prepareStackTrace = (_, stack) => stack;
   const err = new Error();
-  Error.captureStackTrace(err, getCallerFilePath);
+  Error.captureStackTrace(err, getCallerDirname);
   const stack = err.stack as any;
   Error.prepareStackTrace = orig;
-  return stack[1].getFileName();
+  const callerFilePath = stack[1].getFileName();
+  /* istanbul ignore next */
+  return path.dirname(
+    callerFilePath.startsWith('file://')
+      ? callerFilePath.substring(7)
+      : callerFilePath
+  );
 };
 
 /**
  * Find the module file path by checking for available extensions
  * as defined by VALID_FILE_EXTENSIONS
  *
- * @param {string} modulePath - The path to the module
- * @param {string} basePath - The base path for the module
- * @returns {string} The resolved file path
- * @throws {Error} If the file is not found
+ * @param {string} filePath The absolute path to the file
+ * @returns {string} The resolved file path with appended extension
+ * @throws {Error} If the file path does not match any valid extensions
  */
-export const findModuleFile = (modulePath: string, basePath: string): string => {
-  const filePath = path.join(basePath, modulePath);
-  if (fs.existsSync(filePath)) {
-    return filePath;
-  }
-  if (!path.extname(filePath)) {
-    for (const ext of VALID_FILE_EXTENSIONS) {
-      const extFilePath = path.join(basePath, `${modulePath}${ext}`);
-      if (fs.existsSync(extFilePath)) {
-        return extFilePath;
-      }
+const findFileWithExtensions = (filePath: string): string => {
+  for (const ext of VALID_FILE_EXTENSIONS) {
+    const extFilePath = `${filePath}${ext}`;
+    if (fs.existsSync(extFilePath)) {
+      return extFilePath;
     }
   }
   throw new Error(
     `No such file '${filePath}' with matching extensions [${VALID_FILE_EXTENSIONS}]`
   );
 };
 
+/**
+ * Find the module file path
+ *
+ * @param {string} modulePath - The path to the module
+ * @param {string} basePath - The base path for the module
+ * @returns {string} The resolved file path
+ * @throws {Error} If the file is not found
+ */
+export const findModuleFile = (basePath: string, modulePath: string): string => {
+  const filePath = path.join(basePath, modulePath);
+  return fs.existsSync(filePath) ? filePath : findFileWithExtensions(filePath);
+};
+
 /**
  * Appends the name of the node given to the appropriate symbol
  *

src/jewire.ts

@@ -1,8 +1,7 @@
-import path from 'path';
 import rewire from 'rewire';
 import entityClone from './clone';
 import { Options } from './types';
-import { findModuleFile, getCallerFilePath, getModuleHiddenExports } from './files';
+import { findModuleFile, getCallerDirname, getModuleHiddenExports } from './files';
 
 /**
  * Leverages rewire to extract hidden exports from a JavaScript module, but
@@ -16,8 +15,8 @@ import { findModuleFile, getCallerFilePath, getModuleHiddenExports } from './fil
  */
 const jewire = (relativePath: string, options: Options = {}): Record<string, any> => {
   const filePath = findModuleFile(
-    relativePath,
-    options.basePath ?? path.dirname(getCallerFilePath())
+    options.basePath ?? getCallerDirname(),
+    relativePath
   );
   const hiddenExportInfo = getModuleHiddenExports(filePath);
   const hiddenExports = Object.values(hiddenExportInfo.symbols).flat();