Fix position chart for missing historical data (#284)

* Fix position chart for missing historical data

* Update changelog

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Fixed
+
+- Fixed the position detail chart if there are missing historical data around the first buy date
+
 ## 1.36.0 - 09.08.2021
 
 ### Changed

apps/api/src/app/portfolio/portfolio.service.ts

@@ -362,8 +362,17 @@ export class PortfolioService {
       );
 
       const historicalDataArray: HistoricalDataItem[] = [];
-      let maxPrice = marketPrice;
-      let minPrice = marketPrice;
+      let maxPrice = orders[0].unitPrice;
+      let minPrice = orders[0].unitPrice;
+
+      if (!historicalData[aSymbol][firstBuyDate]) {
+        // Add historical entry for buy date, if no historical data available
+        historicalDataArray.push({
+          averagePrice: orders[0].unitPrice,
+          date: firstBuyDate,
+          value: orders[0].unitPrice
+        });
+      }
 
       if (historicalData[aSymbol]) {
         let j = -1;