isvalid.js

/**
 * Checks if the textarea is valid
 */
isValid() {
    const { node, maximum, textarea } = this;
    const { length: inputLength } = textarea.value;
  
    if (!node.hasAttribute('data-required')) return true;
  
    try {
      guardRequired(node, inputLength);
      guardMaxLength(node, inputLength, maximum);
    } catch (errorMessage) {
      this.errorMessage = errorMessage;
      return false;
    }
  
    return true;
}

guardRequired(node, inputLength) {
  if (inputLength === 0) {
    throw node.getAttribute('data-message_required');
  }
}

guardMaxLength(node, inputLength, maximum) {
  if (maximum && inputLength > maximum) {
    throw node.getAttribute('data-message_max');
  }
}