Simple Analytics tracking with a Shopify Custom Pixel. Add this as JS in the Customer Events custom pixel. Since Simple Analytics is privacy aware, you can enable to fire the pixel always. Replace the hostname with your own, after adding it to Simple Analytics. It uses the Server Side API for the sandboxed events.

pixel.js

var SA_HOSTNAME = 'yourhostname.nl';
var SA_ENDPOINT = 'https://queue.simpleanalyticscdn.com/events';

// Send a pageview or event to Simple Analytics via the server-side API
function saPost(payload) {
  var data = Object.assign({
    hostname: SA_HOSTNAME,
    https: true,
    ua: navigator.userAgent,
    referrer: document.referrer || '',
    viewport_width: window.innerWidth,
    viewport_height: window.innerHeight,
    language: navigator.language
  }, payload);

  fetch(SA_ENDPOINT, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(data),
    keepalive: true
  });
}

// Page view on every page load
analytics.subscribe('page_viewed', function(event) {
  saPost({
    type: 'pageview',
    event: 'pageview',
    path: event.context.document.location.pathname
  });
});

// Checkout started
analytics.subscribe('checkout_started', function(event) {
  saPost({
    type: 'event',
    event: 'begin_checkout',
    path: event.context.document.location.pathname,
    metadata: {
      value: event.data.checkout.totalPrice.amount,
      currency: event.data.checkout.totalPrice.currencyCode
    }
  });
});

// Purchase completed
analytics.subscribe('checkout_completed', function(event) {
  saPost({
    type: 'event',
    event: 'purchase',
    path: event.context.document.location.pathname,
    metadata: {
      value: event.data.checkout.totalPrice.amount,
      currency: event.data.checkout.totalPrice.currencyCode,
      order_id: event.data.checkout.order.id
    }
  });
});

// Product added to cart
analytics.subscribe('product_added_to_cart', function(event) {
  var item = event.data.cartLine.merchandise;
  saPost({
    type: 'event',
    event: 'add_to_cart',
    path: event.context.document.location.pathname,
    metadata: {
      product_id: item.product.id,
      product_title: item.product.title,
      price: item.price.amount,
      currency: item.price.currencyCode
    }
  });
});

// Product page viewed
analytics.subscribe('product_viewed', function(event) {
  var product = event.data.productVariant.product;
  saPost({
    type: 'event',
    event: 'view_item',
    path: event.context.document.location.pathname,
    metadata: {
      product_id: product.id,
      product_title: product.title,
      price: event.data.productVariant.price.amount,
      currency: event.data.productVariant.price.currencyCode
    }
  });
});

// Collection page viewed
analytics.subscribe('collection_viewed', function(event) {
  saPost({
    type: 'event',
    event: 'view_item_list',
    path: event.context.document.location.pathname,
    metadata: {
      collection_id: event.data.collection.id,
      collection_title: event.data.collection.title
    }
  });
});