Add simple script to compile es6 to es5 using babel-core

build/build-modules-js/compile-es6.js

@@ -0,0 +1,27 @@
+const glob = require('glob');
+const fs = require('fs');
+const babel = require('babel-core');
+
+const pattern = './**/*.es6.js';
+const options = {
+  ignore: './node_modules/**',
+};
+
+/**
+ * Compiles es6 files to es5.
+ * @param filePath
+ */
+const compileFile = (filePath) => {
+  babel.transformFile(filePath, {}, (error, result) => {
+    if (error) process.exit(1);
+    const fileName = filePath.slice(0, -7);
+    fs.writeFile(`${fileName}.js`, result.code);
+  });
+};
+
+// Compile all files of the given pattern
+glob(pattern, options, (error, files) => {
+  if (error) process.exit(1);
+  files.forEach(compileFile);
+});
+