Add resolveFile helper function

Author: martinRenou

src/index.ts

@@ -1,6 +1,25 @@
 import initializeWasm from './helper';
 import { FilesData, IUnpackJSAPI } from './types';
 
+/**
+ * Resolve file content given its name (resolving symlinks if any)
+ * @param files the current FilesData
+ * @param filename the filename to resolve
+ * @returns the resolved file content
+ */
+export function resolveFile(files: FilesData, filename: string): Uint8Array {
+  if (!files[filename]) {
+    throw new Error(`File ${filename} does not exist.`);
+  }
+
+  if (typeof files[filename] === 'string') {
+    // It's a symlink
+    return resolveFile(files, files[filename]);
+  }
+
+  return files[filename];
+}
+
 export const fetchByteArray = async (url: string): Promise<Uint8Array> => {
   const response = await fetch(url);
   if (!response.ok) {