Moved isEmailValid

src/components/TestForm/emailValidator.ts

+export const isEmailValid = (email: string): boolean => {
+  /**
+   * The following is the RFC 5322 valid email regex
+   * Hinted from question https://stackoverflow.com/questions/201323/how-to-validate-an-email-address-using-a-regular-expression
+   * More on http://emailregex.com/
+   */
+  // eslint-disable-next-line
+  const VALID_EMAIL_REGEX = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
+  return VALID_EMAIL_REGEX.test(String(email).toLowerCase());
+};

src/components/TestForm/index.tsx

@@ -2,6 +2,7 @@ import React, { useState } from 'react';
 import { createStyles, makeStyles, Theme } from '@material-ui/core/styles';
 import TextField from '@material-ui/core/TextField';
 import Button from '@material-ui/core/Button';
+import { isEmailValid } from './emailValidator';
 
 const useStyles = makeStyles((theme: Theme) =>
   createStyles({
@@ -34,21 +35,10 @@ export const Form: React.FC = () => {
   };
   const [formValues, setFormValues] = useState<formData>(defaultValues);
 
-  const isEmailValid = (): boolean => {
-    /**
-     * The following is the RFC 5322 valid email regex
-     * Hinted from question https://stackoverflow.com/questions/201323/how-to-validate-an-email-address-using-a-regular-expression
-     * More on http://emailregex.com/
-     */
-    // eslint-disable-next-line
-    const VALID_EMAIL_REGEX = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
-    return VALID_EMAIL_REGEX.test(String(formValues.email).toLowerCase());
-  };
-
   const handleSubmit = (event: React.FormEvent): void => {
     event.preventDefault();
     const errors: Array<string> = [];
-    if (!isEmailValid()) {
+    if (!isEmailValid(formValues.email)) {
       errors.push('email');
       console.log('Email address not valid');
     } else {