async_example.js

async.each(myContacts, function(contact, messageToSend, callback) {

    const message = {
      from: "+18442849820", 
      to: `+1${contact.number}`,
      text: messageToSend,
      callbackUrl: 'https://happie-match.herokuapp.com/messageCallback'
    };
  
    client.Message.send(message)
      .then(function(message) {
          console.log("Message sent with ID " + message.id);
          callback();
      })
      .catch(function(err) {
          console.log(err.message);
          callback(err);
      });
  
    
}, function(err) {
   
    if( err ) {
      // One of the iterations produced an error.
      // All processing will now stop.
      console.log('There was an error sending SMS');
      console.log(err);
    } else {
      console.log('All SMS sent');
    }
});