GPIO Pin BTN LED naming conventions specific to ESP8266

Mon 2017.01.30

Attempting to learn the BTN and LED naming conventions for the ESP8266
What worked on the Pico causes 'Uncaught ReferenceError' errors when deployed to the ESP8266

Works on the Pico
if( digitalRead(BTN) == 1 )

Uncaught ReferenceError: "BTN" is not defined

Tried BTN0

Ultimately trying to read and write data to a pin and toggle on and off, the onboard and offboard LED's on ESP8266

While this tutorial worked on Pico had the same reference error issue with the LED constants on ESP8266 https://www.espruino.com/Control+LED+wit­h+Button

Uncaught ReferenceError: "LED1" is not defined

Tried LED and LED0

Looked over reference page: http://www.espruino.com/Reference#t_Pin

Pin class This is the built-in class for Pins, such as D0,D1,LED1, or BTN

Looking over the ESP8266 tutorial, no references appear to be made here either
http://www.espruino.com/EspruinoESP8266

Tried searching the Espruino on ESP8266 forum and I attempted the links below, but with no results

http://forum.espruino.com/microcosms/925­/
https://github.com/search?utf8=%E2%9C%93­&q=espruino
https://github.com/espruino/Espruino/tre­e/master/libs

Can someone point me to a Espruino reference link that spells out the convention please.