ValidateDetail.es6

_validate() {
  let valid = true;
  let { username, email } = this,state;
  let errorMessages = {
    username: [],
    email: []
  };
  
  // Null is the default value for the username attribute,
  // as declared in the constructor
  if (username === null || username === '') {
    valid = false;
    errorMessages['username'].push('Username is required');
 }
  
  if (email === null || email === '') {
    valid = false;
    errorMessages['email'].push('Email is required');
  }
  // Observe how if there are no validation errors, 
  // errorMessages will have empty arrays
  this.setState({
    errorMessages: errorMessages
  })
}