```
// Uplink formatter (decoder.js)

function decodeUplink(input) {
  var adc = 0;
  var button = 0;
  button = input.bytes[0];
  adc = input.bytes[1];
  return {
    data: {
      adc: adc << 4,
      button: button
      // bytes: input.bytes,
    }
    // warnings: [],
    // errors: []
  };
}
```


```
// -------------------------------------------------------------------
```

```
// Downlink formatter (encoder.js)

// Called when a downlink with decoded payload is scheduled to be sent to
// device. The result is an encoded array of bytes.
// input is either { "led": "on" } or { "led": "off" }

var led_state = ["off", "on"];

function encodeDownlink(input) {
    var b = 0;
    if (input.data.led == "on") {
        b = 1
    }
    return {
        bytes: [b],
        fPort: 1,
        warnings: [],
        errors: []
    };
}

// Decodes the binary payload back to decoded payload.
function decodeDownlink(input) {
    return {
        data: {
            // bytes: input.bytes
            led: led_state[input.bytes[0]]
        },
        warnings: [],
        errors: []
    }
}
```