This library permits to retrieve weather information from the device.
You can choose your favourite weather provider between Yahoo, OpenWeatherMap, DarkSky and WeatherUnderground Weatherbit

npm i fitbit-weather

Create an index.js file in the companion folder if you don't already have one.
Add the following code in this file :

import * as weather from 'fitbit-weather/companion'

weather.setup({ provider : weather.Providers.yahoo, apiKey : 'YOUR_KEY' })

Add the following code in your app/index.js file

import * as weather from 'fitbit-weather/app'

weather.fetch(30 * 60 * 1000) // return the cached value if it is less than 30 minutes old 
  .then(weather => console.log(JSON.stringify(weather)))
  .catch(error => console.log(JSON.stringify(error)))

• companion.setup({ provider, apiKey}) : configure the provider / apiKey used to fetch the weather
• app.fetch(maximumAge = 0) : retrieve the weather, if given the parameter is the maximum age in milliseconds of a possible cached weather data that is acceptable to return. Default is 0
• app.get() : returns immediately the last cached weather data (the value can be undefined when no data has been received)

  {
    "temperatureC":15,
    "temperatureF":59,
    "location":"Castelnau-D'Estretefonds",
    "description":"Mostly Clear",
    "isDay":false,
    "conditionCode":0,
    "realConditionCode":"this is the real conditioncode returned by the provider",
    "sunrise":1507442496594,
    "sunset":1507483356594,
    "timestamp":1507496916594
  }

const Conditions = {
  ClearSky        : 0,
  FewClouds       : 1,
  ScatteredClouds : 2,
  BrokenClouds    : 3,
  ShowerRain      : 4,
  Rain            : 5,
  Thunderstorm    : 6,
  Snow            : 7,
  Mist            : 8,
  Unknown         : 1000,
}

const Providers = {
  yahoo           : "yahoo",
  openweathermap  : "owm",
  wunderground    : "wu",
  darksky         : "darksky",
  weatherbit      : "weatherbit"
}

I'm not a javascript expert so every comment/code reactoring/best practice is appreciated. Don't hesitate to make PR and tell me what's wrong.