From 9d6abf3164566e6c41af7e449794a2a147ed4201 Mon Sep 17 00:00:00 2001
From: Alexander Zobnin <alexanderzobnin@gmail.com>
Date: Fri, 29 Apr 2022 14:44:26 +0300
Subject: [PATCH] Fix EMA function crash when first point is null

---
 pkg/timeseries/moving_average.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pkg/timeseries/moving_average.go b/pkg/timeseries/moving_average.go
index 12c93eb..23788f9 100644
--- a/pkg/timeseries/moving_average.go
+++ b/pkg/timeseries/moving_average.go
@@ -77,8 +77,11 @@ func (ts TimeSeries) ExponentialMovingAverage(an float64) TimeSeries {
 	var a float64
 	var n int
 	ema := []TimePoint{ts[0]}
-	emaPrev := *ts[0].Value
 	var emaCurrent float64
+	var emaPrev float64 = 0
+	if ts[0].Value != nil {
+		emaPrev = *ts[0].Value
+	}
 
 	if an > 1 {
 		// Calculate a from window size