This is the cartjs from Weezie

cart.js

import $ from 'jquery'
import {bus} from '../helpers/bus.js'
import * as template from '../templates/cart.js'

const render = (cart = window.Cart.cart, item) => {
  template.confirm(item)
  template.count(cart.item_count)
  template.items(cart.items)
  template.totals(cart.total_price)
  bus.emit('cart:bind')
}

const addClick = e => {
  e.preventDefault()
  let input = document.querySelector(`.js-product-quantity[data-product="${e.target.dataset.product}"]`)
  let quant = input.value
  let id = e.target.dataset.add
  let embroidery = document.querySelector(`.js-embroidery-input[data-product="${e.target.dataset.product}"]`)
  let embroideryText = document.querySelector(`.js-embroidery-input[data-product="${e.target.dataset.product}"]`)
  let embroideryColor = document.querySelector(`.js-select-embroidery-color.is-active[data-product="${e.target.dataset.product}"]`)
  let embroideryStyle = document.querySelector(`.js-select-embroidery-style.is-active[data-product="${e.target.dataset.product}"]`)
  let options
  embroidery
    // ? options = {embroiderytext: embroidery.value, embroiderycolor: 'color', embroiderystyle: 'style'}
    ? options = {embroiderytext: embroideryText.value, embroiderycolor: embroideryColor.dataset.value, embroiderystyle: embroideryStyle.dataset.value}
    : options = {}
  bus.emit('cart:add', id, quant, options)
}

const removeClick = e => {
  e.preventDefault()
  let id = e.target.dataset.remove
  bus.emit('cart:remove', id)
}

const quantityChange = e => {
  let id = e.target.dataset.product
  let quant = e.target.value
  bus.emit('cart:quantity', id, quant)
}

const add = (id, quant, props = {}) => {
  let ids = window.Cart.cart.items.map(item => item.id)
  if(ids.includes(parseInt(id))) {
    bus.emit('cart:update', id, quant)
    return
  }
  window.Cart.addItem(id, quant, props, {
    "success": function(data, textStatus, jqXHR) {
    }
  })
}

const remove = (id) => {
  window.Cart.removeItemById(id, {}, {
    "success": function(data, textStatus, jqXHR) {
    }
  })
}

const update = (id, quant) => {
  let target = window.Cart.cart.items.filter(item => item.id == id)
  let newQuant = target[0].quantity + parseInt(quant)
  window.Cart.updateItemById(id, newQuant, {}, {
    "success": function(data, textStatus, jqXHR) {
    }
  })
}

const quantity = (id, quant) => {
  window.Cart.updateItemById(id, quant, {}, {
    "success": function(data, textStatus, jqXHR) {
    }
  })
}

const note = message => {
  window.Cart.setNote(message)
}

const bind = () => {
  let addButtons = Array(...document.querySelectorAll('.js-add-to-cart'))
  addButtons.forEach(button => {
    button.removeEventListener('click', addClick)
    button.addEventListener('click', addClick)
  })
  let removeButtons = Array(...document.querySelectorAll('.js-remove-from-cart'))
  removeButtons.forEach(button => {
    button.removeEventListener('click', removeClick)
    button.addEventListener('click', removeClick)
  })
  let quantity = Array(...document.querySelectorAll('.js-quantity'))
  quantity.forEach(node => {
    node.removeEventListener('change', quantityChange)
    node.addEventListener('change', quantityChange)
  })
  $(document).on('cart.requestComplete', function(event, cart) {
    bus.emit('cart:render', window.Cart.cart)
  })
}

export const listen = () => {
  bus.register({
    channel: 'cart:add',
    emits: 'ID, N',
    description: 'Adds `N` items of the product `ID` to the cart.'
  })
  bus.register({
    channel: 'cart:remove',
    emits: 'ID',
    description: 'Removes all items of of the product `ID`.'
  })
  bus.register({
    channel: 'cart:update',
    emits: 'ID, N',
    description: 'Sets the count of the items with the product `ID` to `N`.'
  })
  bus.register({
    channel: 'cart:quantity',
    emits: 'ID, N',
    description: 'Sets the count of the items with the product `ID` to `N`.'
  })
  bus.register({
    channel: 'cart:note',
    emits: 'Message',
    description: 'Sets a note on the Cart to `Message`'
  })
  bus.register({
    channel: 'cart:bind',
    emits: 'n/a',
    description: 'Binds DOM nodes for Cart UI.'
  })
  bus.register({
    channel: 'cart:render',
    emits: 'Cart',
    description: 'Renders the templates with the Cart object and attaches to a DOM node.'
  })

  bus.on('cart:add', add)
  bus.on('cart:remove', remove)
  bus.on('cart:update', update)
  bus.on('cart:quantity', quantity)
  bus.on('cart:note', note)
  bus.on('cart:bind', bind)
  bus.on('cart:render', render)

  bus.emit('cart:bind')
}