מדידת begin_checkout ב-WooCommerce

add_action( 'woocommerce_before_checkout_form', 'doffice_ga4_begin_checkout', 20 );

/**
 * Assembles a GA4 "begin_checkout" event in PHP at checkout page load,
 * then prints an inline script that pushes it to the dataLayer.
 * The DATA is built server-side, but the EVENT itself fires in the browser.
 * This guide targets the CLASSIC checkout only (not Cart & Checkout Blocks).
 */
function doffice_ga4_begin_checkout() {
    // Bail if WooCommerce isn't active, or we're in the admin.
    if ( ! function_exists( 'WC' ) || is_admin() ) {
        return;
    }
    // Run only on the front-end checkout page.
    if ( ! function_exists( 'is_checkout' ) || ! is_checkout() ) {
        return;
    }
    if ( ! WC()->cart || WC()->cart->is_empty() ) {
        return;
    }

    $items = array();

    foreach ( WC()->cart->get_cart() as $cart_item ) {
        $product    = $cart_item['data'];
        $product_id = $cart_item['product_id'];
        $qty        = max( 1, (int) $cart_item['quantity'] );
        $categories = wp_get_post_terms( $product_id, 'product_cat', array( 'fields' => 'names' ) );

        // line_total is the price AFTER discounts (what the customer actually pays).
        $line_total = (float) $cart_item['line_total'];

        $item = array(
            'item_id'       => $product->get_sku() ? $product->get_sku() : (string) $product_id,
            'item_name'     => $product->get_name(),
            'item_category' => ! empty( $categories ) ? $categories[0] : '',
            // GA4 expects the PER-UNIT price (before multiplying by quantity).
            'price'         => round( $line_total / $qty, 2 ),
            'quantity'      => $qty,
        );

        // item_variant is sent ONLY for variable products.
        if ( $product->is_type( 'variation' ) ) {
            $item['item_variant'] = wc_get_formatted_variation( $product, true );
        }

        // item_brand (OPTIONAL). "product_brand" is NOT built into WooCommerce; it
        // comes from a brands plugin (WooCommerce Brands / Perfect Brands / YITH...).
        // Change the taxonomy name below if your store uses a different one.
        $brands = wp_get_post_terms( $product_id, 'product_brand', array( 'fields' => 'names' ) );
        if ( ! is_wp_error( $brands ) && ! empty( $brands ) ) {
            $item['item_brand'] = $brands[0];
        }

        $items[] = $item;
    }

    // Let WooCommerce compute the total. It already handles tax, shipping, fees,
    // coupons, compound tax and currency switchers, so we don't add them by hand.
    $totals = WC()->cart->get_totals();

    $ecommerce = array(
        'currency' => get_woocommerce_currency(),   // store currency, ISO 4217 (e.g. "ILS")
        'value'    => round( (float) $totals['total'], 2 ),
        'items'    => $items,
    );

    // Applied coupon(s), if any.
    $coupons = WC()->cart->get_applied_coupons();
    if ( ! empty( $coupons ) ) {
        $ecommerce['coupon'] = implode( ', ', $coupons );
    }

    // Stable event_id for later Meta Pixel + CAPI deduplication (GA4 ignores it).
    // Tied to the customer + cart state, so it stays stable while the cart is unchanged.
    $event_id = 'checkout_' . md5( WC()->session->get_customer_id() . WC()->cart->get_cart_hash() );

    $datalayer = array(
        'event'     => 'begin_checkout',
        'event_id'  => $event_id,
        'ecommerce' => $ecommerce,
    );

    echo '<script>';
    echo 'window.dataLayer = window.dataLayer || [];';
    echo 'window.dataLayer.push({ ecommerce: null });';
    echo 'window.dataLayer.push(' . wp_json_encode( $datalayer ) . ');';
    echo '</script>';
}

window.dataLayer.filter(e => e.event === "begin_checkout")

// Expected on the checkout page:
[
  {
    event: "begin_checkout",
    event_id: "checkout_9f8e7d6c5b4a...",
    ecommerce: {
      currency: "ILS",
      value: 712.40,
      coupon: "WELCOME10",
      items: [
        { item_id: "SKU-1", item_name: "...", price: 349.90, quantity: 2, item_variant: "Color: Blue, Size: L" }
      ]
    }
  }
]