title: What is the meaning of this code in React Native and Typescript?
body: <p>I have read some codes of my company's project and see something strange and do not know what it is.</p>
  <p>What is the meaning of the last '&amp;' and an object { invalidMail?: string, ... }?</p>
  <pre><code>const InputValidation: React.ForwardRefExoticComponent&lt;
    React.PropsWithoutRef&lt;IInputValidationProps&gt; &amp; React.RefAttributes&lt;TextInput&gt;
  &gt; &amp; {
    invalidMail?: string;
    invalidNumber?: string;
    invalidPhone?: string;
    isRequired?: string;
    notPositiveNumber?: string;
    lessThanMinLength?: string;
  } = forwardRef&lt;TextInput, IInputValidationProps&gt;((props, ref) =&gt; { ... }
  
  InputValidation.invalidMail = 'Mail không hợp lệ';
  InputValidation.invalidNumber = 'Số không hợp lệ';
  InputValidation.invalidPhone = 'Số điện thoại không hợp lệ';
  InputValidation.isRequired = 'Bắt buộc';
  InputValidation.notPositiveNumber = 'Không nhận giá trị âm';
  InputValidation.lessThanMinLength = 'Số kí tự tối thiểu ';
  </code></pre>
  <p>Does anybody know how this code affect InputValidation component? Thank in advance.</p>