cache-manager.js

import LRU from 'lru-cache'

const options = {
  max: 40000,
  maxAge: 8000 * 60 * 60
}

const cache = LRU(options)

export function checkCache(key) {
  const cachedData = cache.get(key)

  return new Promise(function(resolve, reject) {
    if (cachedData !== undefined) {
      return resolve(cachedData)
    } else {
      reject()
    }
  })
}

export function setCache(key, data) {
  cache.set(key, data)
}

dummy-implementation.js

  _fetchRawPredictionTides(stationId) {
    const yesterday = moment()
      .add(-1, 'days')
      .format(API_DATE_FORMAT)
    const future = moment(yesterday, API_DATE_FORMAT)
      .add(7, 'days')
      .format(API_DATE_FORMAT)

    const params =
      '?begin_date=' +
      yesterday +
      '&end_date=' +
      future +
      '&station=' +
      stationId +
      '&interval=hilo&product=predictions&datum=mllw&units=english&time_zone=gmt&application=web_services&format=json'

    return checkCache(stationId).catch(() => {
      return request(`${process.env.NOAA_URL}`, params).then(json => {
        setCache(stationId, json)
        return json
      })
    })
  }