title: How to do for loop in javascript without blocking
body: <p>I have folowing script </p>
  
  <pre><code>var email_list = ['email1@email.com', 'email2@email.com',....'email100@email.com'];
  for(i=0;i&lt;email_list.length;i++){
    if(checkEmail(email_list[i])){
      //do processing save in db and email to email addresses.
    }
  }
  </code></pre>
  
  <p>This code will be blocking in nodejs how to make this non blocking?</p>