houdini/client/js/common/ff-form-validation/lib/email-regex.es6

// http://stackoverflow.com/questions/46155/validate-email-address-in-javascript
module.exports = /^(([^<>()\[\]\\.,;:\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,}))$/;