Full commit for review

api/modules/formatHandler.js

@@ -0,0 +1,31 @@
+const dns = require('dns');
+
+function isEmailDomainValid(email) {
+	const domain = email.split('@')[1];
+	return new Promise((resolve, reject) => {
+		dns.lookup(domain, (err, address) => {
+			if (err) {
+				reject(err);
+			}
+			else {
+				const isIPAddress = /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/.test(address);
+				resolve(isIPAddress);
+			}
+		});
+	});
+}
+
+function isValidEmail(email) {
+	const emailRegex = /\S+@\S+\.\S+/;
+	return emailRegex.test(email);
+}
+
+function isNumber(x) {
+	return /^-?[\d.]+(?:e-?\d+)?$/.test(x);
+}
+
+module.exports = {
+	isEmailDomainValid,
+	isValidEmail,
+	isNumber,
+};