title: Reactive form validation in angular 5 with bootstrap 4
body: <p>I am working to develop a secure form using angular 5 and Bootstrap 4. How can I validate form runtime before form submission? Please guide or share any article regarding reactive validation in angular 5. Where I can learn validation about the text, number, email, description etc.</p>
  
  <p>This is my first question at StackOverflow. Thank you.</p>