snippet for LRU cache for object cache

lru.js

// Get list of cache keys sorted by timestamp.
var keysAsc = _.sortBy(_.pairs(cache), function (x) {
    return x[1].__time;  // Timestamp
}).map(function(x) {
    return x[0];  // URL
});

// Keep popping off expired keys until we're under the quota.
var i = 0;
while (JSON.stringify(cache).length >= settings.offline_cache_limit_request) {
    if (typeof keysAsc[i] !== 'undefined') {
        console.log('Quota exceeded; removing from request cache', keysAsc[i]);
        delete cache[keysAsc[i]];
    }
    i++;
}