Function for reading input from Retrolink NES controller (https://www.gadgetreview.com/retrolink-usb-nes-controller-review) in the browser

retrolink-nes-controller.js

function pollNESController() {
  const gamepads = navigator.getGamepads ? navigator.getGamepads() : (navigator.webkitGetGamepads ? navigator.webkitGetGamepads : []);
  const controllerInput = {
    isPresent: false,
    dpad: '',
    select: 0,
    start: 0,
    a: 0,
    b: 0
  };
  const isPresent = gamepads.length > 0 && gamepads[0] != null;
  const getButton = (index) => {
  	console.log('test');
  	if(!isPresent) {
    	return false;
    }
    return gamepads[0].buttons[index].pressed;
  };
  controllerInput.isPresent = isPresent;
  if(getButton(14)) {
    controllerInput.dpad = 'left';
  }
  else if(getButton(15)) {
    controllerInput.dpad = 'right';
  }
  else if(getButton(12)) {
  	controllerInput.dpad = 'up';
  }
  else if(getButton(13)) {
  	controllerInput.dpad = 'down';
  }
  controllerInput.select = getButton(8);
  controllerInput.start = getButton(9);
  controllerInput.a = getButton(1);
  controllerInput.b = getButton(0);
  return controllerInput;
}