Get global module variable in vanilla javascript

So i have below module created according to an example i found.

I initialize it with

equipment_booking = new equipment({
    equipment: '#equipment_order',
    type: '#equipment_type_order',
    validation: '#equipment_validation_order',
    submit: "#submit_booking"
});

What I want to do is access the typeVar from outside the module. I found out that I need to use the this. in front of it. And indeed I could access it. However I can’t seem to access it inside the module functions. How would I accomplish this? This is a part of the module I have written. I have tried different ways in the checkInput function. Any help or suggestions are realy appriciated.

var equipment = (function() {
    function equipment(options) {
        // Set the standard options
        var o = {
            equipment: null,
            type: null,
            validation: null,
            submit: null
        };

        // Get some other needed variables
        number = "";
        this.typeVar = 0;
        var error = [{
            code: 0,
            msg: ""
        }];

        // Then we can override the given options to the standard options
        for (var k in options) {
            if (options.hasOwnProperty(k)) {
                o[k] = document.querySelector(options[k]);
            }
        }

        // Add the eventlisteners
        o.equipment.addEventListener('keydown', checkInput);
        o.equipment.addEventListener('blur', validateInput);
        o.type.addEventListener('change', validateInput);

        function checkInput(e) {
            console.log("CheckInput called"); // This console.log is called
            console.log(typeVar);             // Error: typeVar is not defined
            console.log(this.typeVar);        // Undefined
            e.preventDefault();               // The e works
        }

        function validateInput() {
            // Validating input
        }
    }
    return equipment;
})();