index.js

// main process then
const { app } = require('electron')
const fs = require('fs')

const directory = app.getPath('home') // /home folder on OS X
const cacheDirectory = `${directory}/twitch-bot-cache` // /home/twitch-bot-cache/
const cacheDataFile = `${cacheDirectory}/data.json` // /home/twitch-bot-cache/data.json

// "cached now" object
let caches = {}

// if cacheDirectory isn't available, we create it
if (fs.existsSync(cacheDirectory) === false) {
  fs.mkdirSync(cacheDirectory)
}

// fsCache object, contains functions, etc.
export const fsCache = {
  key(name, value) {
    // example: fsCache.key('button', 'is green'), fsCache.key('super_button', { is: 'green' })
    caches[name] = value
    // rewrites cache file with new data
    fs.writeFileSync(cacheDataFile, JSON.stringify(caches, null, 2))
  }
}

export function readFromCache(file, callback) {
  try {
    // read cache file
    const cacheContent = fs.readFileSync(
      `${cacheDirectory}/${file}.json`,
      'utf-8'
    )
    
    // run callback with file content (cached data, etc.)
    callback(cacheContent)
  } catch (err) {
    console.log('Error in Cache:', err)
  }
}