nodejs - key/value cache with efficient lru flush algorithm

gistfile1.txt

  my.Cache = function(ll) {
    this.l1 = {}; this.l2 = {}; this.ii = 0; this.ll = ll || 256;
  };
  my.Cache.prototype = {
    'flush': function() {this.l1 = {}; this.l2 = {}; this.ii = 0;},
    'get': function(kk, vv0) {
      this.ii += 1;
      return this.l1[kk] === undefined ? this.l1[kk] = vv0 : this.l2[kk] = this.l1[kk];
    },
    'set': function(kk, vv) {
      //// flush cache if counter ii > ll
      if((this.ii += 1) > this.ll) {this.l1 = this.l2; this.l2 = {}; this.ii = 0;}
      this.l1[kk] = this.l2[kk] = vv;
      //// return true if cache will be flushed on next write
      //// giving caller the opportunity to backup data
      return this.ii >= this.ll;
    }
  };