From 3b9db65ea33890e9fa5e911ea4170e4b31fd03be Mon Sep 17 00:00:00 2001
From: "Earle F. Philhower, III" <earlephilhower@yahoo.com>
Date: Sun, 14 Apr 2019 15:33:15 -0700
Subject: [PATCH] Add String::toDouble from upstream Arduino core (#5986)

Fixes #5985
---
 cores/esp8266/WString.cpp | 11 +++++++++--
 cores/esp8266/WString.h   |  1 +
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/cores/esp8266/WString.cpp b/cores/esp8266/WString.cpp
index d949e2904..69444696a 100644
--- a/cores/esp8266/WString.cpp
+++ b/cores/esp8266/WString.cpp
@@ -829,17 +829,24 @@ void String::trim(void) {
 // /*********************************************/
 
 long String::toInt(void) const {
-    if(buffer())
+    if (buffer())
         return atol(buffer());
     return 0;
 }
 
 float String::toFloat(void) const {
-    if(buffer())
+    if (buffer())
         return atof(buffer());
     return 0;
 }
 
+double String::toDouble(void) const
+{
+    if (buffer())
+        return atof(buffer());
+    return 0.0;
+}
+
 // global empty string to allow returning const String& with nothing
 
 const String emptyString;
diff --git a/cores/esp8266/WString.h b/cores/esp8266/WString.h
index aecf9b4a6..11b12aa08 100644
--- a/cores/esp8266/WString.h
+++ b/cores/esp8266/WString.h
@@ -241,6 +241,7 @@ class String {
         // parsing/conversion
         long toInt(void) const;
         float toFloat(void) const;
+	double toDouble(void) const;
 
     protected:
         // Contains the string info when we're not in SSO mode