Full Stack Web Development with Raspberry Pi 3

Putting the functions together in a module

To create a module, place all the preceding functions in a single file and export them so that they can be used by other parts of our application:

    /*
    We have to first instantiate the "db" database instance    before using it in our functions
    */
    const sqlite3 = require('sqlite3')
    const path = require('path')
    const db = new     sqlite3.Database(path.resolve('./.sqlite.db'))

    const insertReading = (type, reading) => {
      db.run(`INSERT INTO ${type} VALUES (datetime('now'),        ${reading});`)
    }

    const fetchLatestReadings = (type, limit, callback) => {
      db.all(`SELECT * FROM temperature ORDER BY createdAt     DESC LIMIT ${limit}`, callback)
    }

    const fetchReadingsBetweenTime = (type, start, end,     callback) => {
      db.all ...