To turn on the led you need to load the gpio_api.js file.

LED Turn ON/OFF

Note : This below example was tested mongoose os with java script app demo-js in ESP8266 NodeMCU Dev Board(ESP-12E)

• This below example turn on the LED GPIO-4 (NodeMCU Dev Board digital pin 2)
• Set the GPIO pin mode as OUPUT uisng gpio set mode function ex: GPIO.set_mode(led, GPIO.MODE_OUTPUT)
• Turn off the LED call the gpio write function with low-0 ex : GPIO.write(led, 0) .
• Turn on the LED call the gpio write function with low-1 ex : GPIO.write(led, 1) .

Code

load('api_gpio.js');
 
// Configure LED
let led = 4; //lde pin GPIO04
GPIO.set_mode(led, GPIO.MODE_OUTPUT);
GPIO.write(led,1);

LED turn ON/OFF using button

• Use Boot button(GPIO-0)
• The example code used blink in-build LED, It’s connected to GPIO-10.
• You can change any other pin Ex : led = 4; // Get LED GPIO-04 pin; 
• Note : Code 1 and Two are same application and functionality. Main difference is calling function.

Code 1 :

• Used GPIO-0 pin (Boot button in NodeMCU Dev Board), as interrupt and used Button interrupt handler function.

// http://www.ArunEworld.com/Embedded/ESPressif/ESP8266/ESP8266_Mongoose-os/
// Tested By  : Arun(20170430)
// Example Name : AEW_LED-Blink_Using_Button.js
// Firmware  : Mongoose OS for ESP32
//*******************************//
// This example demonstrates how to react on a button press by toggling LED.
//
// To try this example,
//   1. Download <code>{{EJS1}}</code> tool from https://mongoose-os.com/software.html
//   2. Run <code>{{EJS2}}</code> tool and install Mongoose OS
//   3. In the UI, navigate to the <code>{{EJS3}}</code> tab and load this example

// Load Mongoose OS API
load('api_gpio.js');

// Configure LED
let led = ffi('int get_led_gpio_pin()')();  // Get built-in LED GPIO pin
GPIO.set_mode(led, GPIO.MODE_OUTPUT);

let pin = 0;   // GPIO 0 is typically a 'Flash' button
GPIO.set_button_handler(pin, GPIO.PULL_UP, GPIO.INT_EDGE_NEG, 200, function(x) {
  let value = GPIO.toggle(led);
  print('Button press, pin:', x, 'LED pin:', led, ' Value: ', value);
}, true);

print('Flash button is configured on GPIO pin ', pin);
print('Press the flash button now!');

Code 2:

• In this code i was used GPIO-0 pin (Boot button in NodeMCU dev Kit) as interrupt and used interrupt handler function.
• If your using interruot handler function then you need o enable the interrupt using GPIO.enable_int(pin)  function

load('api_gpio.js');

GPIO.set_mode(4, 1);
//GPIO.write(10, 0);


GPIO.set_int_handler(0, GPIO.INT_EDGE_NEG, function(pin) {
   print('Pin', 0, 'got interrupt');
   GPIO.toggle(4);
   
}, null);
GPIO.enable_int(0);