MeteorJS email form validation

Total novice here. I'm trying to do a client side form validation for a subscribe to newsletter form. My client side code is such.

Template.body.events({
    "submit .new-subscriber": function (event) {
      // This function is called when the new task form is submitted
      var newEmail = event.target.newEmail.value;
     if (newEmail is email?){

     Meteor.call("addNewSubscriber", newEmail);
     }

I'm not sure how to perform form validation here? Can I perform the same server side?