IndexDB to SQLite3

index.js

const sqlite3 = require('sqlite3')
const fs = require('fs')

let dbpath = 'common.db'
let finished = 0, total = 0

let mydb = new sqlite3.Database(dbpath)
if (fs.existsSync(dbpath)) {
   fs.unlinkSync(dbpath)
}

mydb.run('CREATE TABLE data(id INTEGER PRIMARY KEY AUTOINCREMENT, `database` TEXT, `table` TEXT, `key` TEXT, `value` TEXT)')

function onOpen(event)
{
    let storeNames = event.target.result.objectStoreNames
    Object.values(storeNames).forEach((name) => {
        total ++
        onStore(event.target.result, name)
    })
}

function onStore(cursor, storeName)
{
    let store = cursor.transaction([storeName], 'readonly').objectStore(storeName)
    store.openCursor().onsuccess = (event) => {
        let result = event.target.result
        if (result == null) {
            finished ++
            console.log('Done writing ' + storeName + ' (' + finished + ' / ' + total + ')')

            if (finished == total)
            {
                console.log('All done, closing window')
                mydb.close()
            }

            return
        }

        mydb.run('INSERT INTO data(`database`, `table`, `key`, `value`) VALUES(?, ?, ?, ?)',
            [cursor.name, storeName, result.key, JSON.stringify(result.value)],
            function (err) {
                if (err) {
                    return console.log(err.message);
                }
            })

        result.continue()
    }
}

setTimeout(() => {
    indexedDB.databases().then(result => {
        result.forEach((row) => {
            indexedDB.open(row.name).onsuccess = onOpen
        })
    })
}, 1000)