Signup data is reaching the server code

common/utilities/validate-username.js

@@ -0,0 +1,23 @@
+module.exports = username => {
+	if (!username) {
+		return false;
+	}
+
+	if (username.length < 8 && username.length > 100) {
+		return false;
+	}
+	
+	if (!isAlpha(username)) {
+		return false;
+	}
+	
+	return true;
+}
+
+const isAlpha = (str) => {
+	//starting from beginning ^
+	//to the end $
+	//check first letter is alpha or underscore [A-Za-z_]
+	//check the remaining 0 or more (*) letters are alpha, numeric or underscore [A-Za-z0-9_]
+	return /^[A-Za-z_][A-Za-z0-9_]*$/.test(str);
+}