Add stats data helpers for average order value

Author: rachelmcr

WooCommerce/Classes/ViewRelated/Dashboard/Factories/StatsV4DataHelper.swift

@@ -37,6 +37,18 @@ final class StatsV4DataHelper {
         }
     }
 
+    /// Creates the text to display for the average order value.
+    ///
+    static func createAverageOrderValueText(orderStatsData: OrderStatsData, currencyFormatter: CurrencyFormatter, currencyCode: String) -> String {
+        if let value = averageOrderValue(orderStats: orderStatsData.stats) {
+            // If order value is an integer, no decimal points are shown.
+            let numberOfDecimals: Int? = value.isInteger ? 0 : nil
+            return currencyFormatter.formatAmount(value, with: currencyCode, numberOfDecimals: numberOfDecimals) ?? String()
+        } else {
+            return Constants.placeholderText
+        }
+    }
+
     // MARK: Views and Visitors Stats
 
     /// Creates the text to display for the visitor count.
@@ -104,6 +116,16 @@ private extension StatsV4DataHelper {
         }
     }
 
+    /// Retrieves the average order value for the provided order stats.
+    ///
+    static func averageOrderValue(orderStats: OrderStatsV4?) -> Decimal? {
+        if let orderStats {
+            return orderStats.totals.averageOrderValue
+        } else {
+            return nil
+        }
+    }
+
     /// Retrieves the total revenue from the provided order stats and, optionally, a specific interval.
     ///
     static func totalRevenue(at selectedIndex: Int?, orderStats: OrderStatsV4?, orderStatsIntervals: [OrderStatsV4Interval]) -> Decimal? {