Validates Email address against regular expression and a list of "allowed" email domains.

react.validate-email.tsx

export function isValidEmail(email: string, acceptedDomains?: string[]) {
	const emailformat = /^(([^<>()[\]\.,;:\s@\"]+(\.[^<>()[\]\.,;:\s@\"]+)*)|(\".+\"))@(([^<>()[\]\.,;:\s@\"]+\.)+[^<>()[\]\.,;:\s@\"]{2,})$/i
	let isValid = false

	if (email.match(emailformat)) {
		isValid = true
		if (acceptedDomains !== undefined) {
			isValid = acceptedDomains.some(function(domain) {
				return email.endsWith(domain)
			})
		}
	} else {
		isValid = false
	}
	return isValid
}