SmsCounter.count is not a function

[leandroluccerini-fintel]

This is my simple code.
On keypress it results in

SmsCounter.count is not a function

Can you help?

var SmsCounter = require('sms-counter');

$(document).ready(function () {
    $('#simple_sms_message').keypress(function () {
        var text = $(this).val();
        var cc = SmsCounter.count(text);
        $("#numChars").html(cc.length);
        $("#numsms").html(cc.messages);
    });

});

Thank you