Email Validation through api(Note : this will work in both record.js and create-actions.js as well)

record.js

 var emailAddress="test@test.com";  
   var self = this,  
       data = {  
             results: [],  
       },  
       options = {},  
       callbacks = {},  
       url;  
       // add the search term to the URL params  
       options.q = emailAddress;  
  
      // the first 10 results should be enough  
      //we can use 2 or 5 any number which is very less.  
      options.max_num = 10;  
                                      
      // build the URL for fetching recipients that match the search term  
      url = app.api.buildURL('Mail', 'recipients/find', null, options);  
      // create the callbacks  
      callbacks.success = function(result) {                                         
          var email_count=result.records.length; //Assigning the count of returned email addresses.  
          if(email_count>0){  
               console.log("This is duplicate email address"); 
          }  
          else{  
             console.log("This is new email address");
          }  
      };  
      callbacks.error = function() {  
          console.log("api error");                                          
      };                                      
      app.api.call('read', url, null, callbacks);