simple jquery snippet to override a native form's with an ajax call

Ajaxify.js

// requires jQuery!

const noop = () => {};
const constant = v => () => v;
const beTrue = constant(true); // () => true;
function $Ajaxify(form, ...callbacks) {

  if (typeof callbacks[0] === 'object') {
    var {
      onSuccess = noop, onError = noop, beforeSend = beTrue
    } = callbacks[0];
  } else {
    var [onSuccess = noop, onError = noop, beforeSend = beTrue] = callbacks;
  }

  jQuery(document).on('submit', form, {
    onSuccess,
    onError
  }, function onSubmit(evt) {
    console.log("im onsubmit");
    evt.preventDefault();
    evt.stopImmediatePropagation();
    evt.stopPropagation();

    if (!beforeSend.apply(this, ...arguments)) return false;

    var $form = jQuery(this);
    jQuery.ajax({
      type: $form.attr('method'),
      url: $form.attr('action'),
      data: $form.serialize(),
      success: evt.data.onSuccess.bind(this),
      error: evt.data.onError.bind(this)
    });
    // to stop propagation
    return false;
  });
}

app.js

// usage example
$Ajaxify("#someForm", {
      beforeSend: function() {
        // if beforeSend returns false, submit is prevented
      },
      onSuccess: function() {
      },
      onError: function() {
      }
    });

// also allows:

$Ajaxify("#myForm", () => "i'm onsubmit", () => "i'm onerror", () => "i'm beforeSend");