day 11

day11/utils/index.js

@@ -0,0 +1,10 @@
+function capitalizeFirstLetter(target) {
+  if (typeof target !== 'string') {
+    throw new Error('Parameter should be a string.');
+  }
+  return target?.substring(0, 1).toUpperCase() + target?.substring(1)?.toLocaleLowerCase();
+}
+
+module.exports = {
+  capitalizeFirstLetter,
+};