From 14269ff8eb5224104dcac42fa644ebc1a3c00485 Mon Sep 17 00:00:00 2001
From: Pavlo Aksonov <aksonov@gmail.com>
Date: Thu, 13 Sep 2018 15:31:15 +0200
Subject: [PATCH] allow to hide back button by providing left={()=>null}

---
 src/navigationStore.js | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/navigationStore.js b/src/navigationStore.js
index 45edbf540..9101da282 100644
--- a/src/navigationStore.js
+++ b/src/navigationStore.js
@@ -297,12 +297,14 @@ function createNavigationOptions(params) {
       || navigationParams.backTitle
       || ((drawerImage || drawerIcon) && !hideDrawerButton && drawerPosition !== 'right')
     ) {
-      res.headerLeft = getValue(navigationParams.left || navigationParams.leftButton || params.renderLeftButton, { ...params, ...navigationParams, ...screenProps })
+      const leftButton = navigationParams.left || navigationParams.leftButton || params.renderLeftButton;
+      res.headerLeft = getValue(leftButton, { ...params, ...navigationParams, ...screenProps })
         || (((onLeft && (leftTitle || navigationParams.leftTitle || leftButtonImage || navigationParams.leftButtonImage)) || drawerImage || drawerIcon) && (
           <LeftNavBarButton {...params} {...navigationParams} {...componentData} />
         ))
         || res.headerLeft
-        || (init ? null : (renderBackButton && renderBackButton(state)) || <BackNavBarButton {...state} />);
+        || (init ? null : (!leftButton && renderBackButton && renderBackButton(state)) || (!leftButton && <BackNavBarButton {...state} />))
+        || null;
     }
 
     if (back) {