db.js

//"use strict";
var database = 'rpt';
var table = 'users';


window.indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB;
window.IDBTransaction = window.IDBTransaction || window.webkitIDBTransaction || window.msIDBTransaction || {
    READ_WRITE: "readwrite"
};
window.IDBKeyRange = window.IDBKeyRange || window.webkitIDBKeyRange || window.msIDBKeyRange;


// open database
let request = window.indexedDB.open(database, 4);

request.onerror = function(event) {
    console.log('db connection error');
};

request.addEventListener('error', (event) => {
    console.log('db request error: ' + request.error);
});

request.onblocked = function(event) {
    console.log('db blocked!');
    console.log(event);
};

// create data structure
request.onupgradeneeded = function(event) {
    console.log('db upgrade');
    db = event.target.result;

    if (db.objectStoreNames.contains(table)) {
        //console.log('deletedb');

        // This may speed up the db delete. Worth checking out.
        // indexedDB.deleteDatabase('rpt')
        db.deleteObjectStore(table);
    }

    var os = db.createObjectStore(table, {
        keyPath: 'name'
    });
    os.createIndex('about', 'about', {
        unique: false
    });
    os.createIndex('comments', 'comments', {
        unique: false
    });
    os.createIndex('stats', 'stats', {
        unique: false
    });
};


// connected to database
request.onsuccess = function(event) {
    //console.log('db success');
    db = event.target.result;
};




function handleQuota(data) {
    let quota = round(data.quota / 1024 / 1024);
    let usage = round(data.usage / 1024 / 1024);

    if (usage > quota * .95) {
        console.log('db usage:', usage, 'MB');
        console.log('db quota:', quota, 'MB');
        console.log('');
        overQuota();
    }
}


function overQuota() {
    //console.log('overQuota');


    let os = db.transaction([table], 'readwrite').objectStore(table);
    //let index = os.index('about');
    let req = os.openCursor();

    // errors
    req.onerror = function(e) {
        console.log('overQuota db error: ' + table + '!');
    };

    req.onsuccess = function(e) {
        if (req.result) {
            let user = req.result.value;

            let day = 60 * 60 * 24;
            let maxAge = Date.now() - (day * 10);

            if (user.about.updated < maxAge) {
                //console.log(maxAge, user.about.updated, user.name);

                let delReq = os.delete(user.name);
                delReq.onerror = function() {
                    console.log('db error: failed to delete', user.name);
                }
                delReq.onsuccess = function() {
                    //console.log('deleted', user.name);
                }
            }


            req.result.continue();
        }
    };
}