weather.js

const superagent = require('superagent');
const cache = {};

function getWeather(request, response) {
  const key = `weather-${request.query.lat}${request.query.lon}`;
  if(!cache[key] || (Date.now() - cache[key].timestamp) > 50000){
    const url = 'https://api.openweathermap.org/data/2.5/onecall';
    const query = {
      appid: process.env.WEATHER_API_KEY,
      lat: request.query.lat,
      lon: request.query.lon,
      }
      superagent.get(url)
        .query(query)
        .then(weatherResponse => {
          const dailyForecasts = weatherResponse.body.daily.map(day => new Forecast(day));
          cache[key] = {};
          cache[key].timestamp = Date.now();
          cache[key].data = dailyForecasts;
          console.log('cache miss');
          response.status(200).send(dailyForecasts);
        })
  } else {
      let cachedData = cache[key].data;
      console.log('Cache hit');
      response.status(200).send(cachedData);
    }
}

function Forecast(day) {
  // Assuming we are passing in weatherResponse.body.daily[i] as the day
  const milli = day.dt * 1000;
  const dateObject = new Date(milli);
  this.date = dateObject.toISOString().substr(0, 10);
  this.description = day.weather[0].description;
}

module.exports = getWeather;