cache.js #1

'use strict';

function makeCache() {
  // object with no prototype
  var cache = Object.create(null);

  // force the jit to immediately realize this object is a dictionary. This
  // should prevent the JIT from going wastefully one direction (fast mode)
  // then going another (dict mode) after
  cache['foo'] = 1;
  delete cache['foo'];

  return cache;
}

module.exports = Cache;
function Cache() {
  this._store = makeCache();
}

Cache.prototype.set = function(key, value) {
  return this._store[key] = value;
};

Cache.prototype.get = function(key) {
  return this._store[key];
};

Cache.prototype.has = function(key) {
  return key in this._store;
};

Cache.prototype.delete = function(key) {
  delete this._store[key];
};

Object.defineProperty(Cache.prototype, 'size', {
  get: function() {
    return Object.keys(this._store).length;
  }
});