Make the build script transpile the utilities

NOTES

@@ -1,2 +0,0 @@
-In the src folder, you can use any version - it will be transpiled to ES2017 by esbuild.
-But in the utils folder, you have to use at most ES2017, because it is not transpiled.

esbuild.config.js

@@ -124,19 +124,12 @@ fs.writeFileSync(__dirname + "/generatedAssets/licenses/index.html", licensesPag
 
 // Bundle the source and copy the assets using esbuild and esbuild-plugin-copy
 esbuild.build({
-  entryPoints: ["src/index.js"], // Your entry file
+  entryPoints: ["src/index.js"],
   bundle: true,
-  outfile: "dist/svr.js", // Output file
+  outfile: "dist/svr.js",
   platform: "node",
   target: "es2017",
   plugins: [
-    esbuildCopyPlugin.copy({
-      resolveFrom: __dirname,
-      assets: {
-        from: ["./utils/**/*"],
-        to: ["./dist"],
-      }
-    }),
     esbuildCopyPlugin.copy({
       resolveFrom: __dirname,
       assets: {
@@ -156,6 +149,20 @@ esbuild.build({
     })
   ],
 }).then(() => {
+  const utilFilesAndDirectories = fs.existsSync(__dirname + "/utils") ? fs.readdirSync(__dirname + "/utils") : [];
+  const utilFiles = [];
+  utilFilesAndDirectories.forEach((entry) => {
+    if (fs.statSync(__dirname + "/utils/" + entry).isFile()) utilFiles.push(entry);
+  })
+
+  // Transpile utilities using esbuild
+  esbuild.build({
+    entryPoints: [utilFiles.map((filename) => "utils/" + filename)],
+    bundle: false,
+    outdir: "dist",
+    platform: "node",
+    target: "es2017",
+  }).then(() => {
     const archiveName = "svr.js." + version.toLowerCase().replace(/[^0-9a-z]+/g,".") + ".zip";
     const output = fs.createWriteStream(__dirname + "/out/" + archiveName);
     const archive = archiver("zip", {
@@ -164,6 +171,9 @@ esbuild.build({
     archive.pipe(output);
     archive.directory("dist/", false);
     archive.finalize();
+  }).catch((err) => {
+    throw err;
+  })
 }).catch((err) => {
   throw err;
 });