basic vanilla JS minibasket, some ES6

minibasket.js

var _btn = document.getElementsByClassName("buy"),
    _basketItems = document.getElementById("basketItems"),
    _basketArr = [];

if(_basketItems !== null) {
    _basketItems.addEventListener("click", getBtn);
}

for (var i=0; i<_btn.length; i++) {
    _btn[i].addEventListener("click", btnClicked);
}

function btnClicked() {

    var 	_price = parseFloat(this.getAttribute("data-price")),
        	_name = this.getAttribute("data-name"),
        	_sku = this.getAttribute("data-sku");

    addToBasket(_price, _name, _sku);
    showProducts();
    basketTotal();
}

function basketTotal(_price, _name, _sku) {

    var grandTotal = _basketArr.reduce(function(total, product) {
        return total += product.Price * product.qty;
    }, 0);

    document.getElementById("total").innerHTML = grandTotal;

}

function addProduct(_price, _name, _sku) {
    _basketArr.push( {
        "Price" : _price, 
        "Name" : _name,
        "Sku" : _sku,
        "qty" : 1
    });
}

function showProducts() {
    var basket = document.getElementById("basketItems");
    basket.innerHTML = "";
    _basketArr.forEach(function(product) {
        basket.innerHTML += createProduct(product);
    });
}

function createProduct(product) {
    return '<ul data-sku="' + product.Sku+ '"><li>Sku: <span class="skus">' + product.Sku + '</span></li>' + '<li>' + product.Name + '</li>' + '<li>Price: ' + product.Price + '</li>' + '<li>' + ' qty: ' + product.qty + '</li><button class="remove" data-sku="'+product.Sku+'">Remove</button></ul>';
}

function addToBasket(price, name, sku) {

    var inBasket = _basketArr.filter(product => sku === product.Sku);
    if(inBasket.length) {
        inBasket[0].qty++;
    }
    else {
        addProduct(price, name, sku)    
    }

}

function getBtn() {
    var elm = event.target,
        esku = elm.getAttribute("data-sku");

    removeProduct(esku);
}

function removeProduct(rsku) {
    _basketArr.forEach(function(product, i) {
        if(product.Sku == rsku) {
            if(product.qty > 1) {
                product.qty--;
            } else {
                _basketArr.splice(i, 1);
            }
            basketTotal();
            showProducts();
        }
    });
}