expando-url.js

// testing the effect of using an ES5 Getter
// to get the parsedUrl on an object

var url = require("url")

function AutoParseUrl (u) {
  this.url = u
}
Object.defineProperty(AutoParseUrl.prototype, "parsedUrl", {get:function () {
  return url.parse(this.url)
}, enumerable:true })

function AutoParseCache (u) {
  this.url = u
}
Object.defineProperty(AutoParseCache.prototype, "parsedUrl", {get:function () {
  if (this._parsedUrl) return this._parsedUrl
  return this._parsedUrl = url.parse(this.url)
}, enumerable:true })

function AutoParseUrlQuery (u) {
  this.url = u
}
Object.defineProperty(AutoParseUrlQuery.prototype, "parsedUrl", {get:function () {
  return url.parse(this.url, true)
}, enumerable:true })

function AutoParseCacheQuery (u) {
  this.url = u
}

Object.defineProperty(AutoParseCacheQuery.prototype, "parsedUrl", {get:function () {
  if (this._parsedUrl) return this._parsedUrl
  return this._parsedUrl = url.parse(this.url, true)
}, enumerable:true });

Object.defineProperty(AutoParseCacheQuery.prototype, 'selfShadowingGetter', {
  get: function () {
    var parsed= url.parse(this.url, true);
    this.__proto__= null;                          // cut momentarily the prototype chain
    this.selfShadowingGetter= parsed;              // shadow the getter
    this.__proto__= AutoParseCacheQuery.prototype; // restore the prototype chain
    return parsed;
  },
  enumerable:true
});

function NoAutoParse (u) {
  this.url = u
}

var u = "/path/to?something=foo#hash-bazoo"
exports.compare =
  { "selfShadowingGetter_NoCache" : function () {
      var req = new AutoParseCacheQuery(u)
      return [req.selfShadowingGetter, req.selfShadowingGetter, req.selfShadowingGetter, req.selfShadowingGetter]
    }
  , "selfShadowingGetter_Cache" : function () {
      var req = new AutoParseCacheQuery(u);
      var up= req.selfShadowingGetter;
      return [up, up, up, up];
    }
  , "auto" : function () {
      var req = new AutoParseUrl(u)
      return [req.parsedUrl, req.parsedUrl, req.parsedUrl, req.parsedUrl]
    }
  , "autoCache" : function () {
      var req = new AutoParseCache(u)
      return [req.parsedUrl, req.parsedUrl, req.parsedUrl, req.parsedUrl]
    }
  , "autoQuery" : function () {
      var req = new AutoParseUrlQuery(u)
      return [req.parsedUrl, req.parsedUrl, req.parsedUrl, req.parsedUrl]
    }
  , "autoCacheQuery" : function () {
      var req = new AutoParseCacheQuery(u)
      return [req.parsedUrl, req.parsedUrl, req.parsedUrl, req.parsedUrl]
    }
  , "noAuto" : function () {
      var req = new NoAutoParse(u)
      return [url.parse(req.url), url.parse(req.url), url.parse(req.url)
             ,url.parse(req.url)]
    }
  , "noAutoCache" : function () {
      var req = new NoAutoParse(u)
        , up = url.parse(req.url)
      return [up, up, up, up]
    }
  , "noAutoCacheQuery" : function () {
      var req = new NoAutoParse(u)
        , up = url.parse(req.url, true)
      return [up, up, up, up]
    }
  , "noAutoQuery" : function () {
      var req = new NoAutoParse(u)
      return [url.parse(req.url, true), url.parse(req.url, true)
             ,url.parse(req.url, true), url.parse(req.url, true)]
    }
  }

require("bench").runMain()

/*

$ node /Users/jorge/Desktop/shadowingGetter.js 
benchmarking /Users/jorge/Desktop/shadowingGetter.js
Please be patient.
Scores: (bigger is better)

noAutoCache
Raw:
 > 522.9540918163673
 > 503.4965034965035
 > 506.98602794411175
 > 521.9560878243512
 > 519.9600798403194
Average (mean) 515.0705581843306

autoCache
Raw:
 > 281.71828171828173
 > 274.9003984063745
 > 271.9123505976096
 > 276.72327672327674
 > 279.72027972027973
Average (mean) 276.99491743316446

noAuto
Raw:
 > 133.46613545816734
 > 129.74051896207584
 > 129.22465208747514
 > 136.45418326693226
 > 130.60817547357925
Average (mean) 131.89873304964595

auto
Raw:
 > 103.8961038961039
 > 103.8961038961039
 > 104.16666666666667
 > 106.46766169154229
 > 102.2840119165839
Average (mean) 104.14210961340014

noAutoCacheQuery
Raw:
 > 21.379980563654033
 > 22.33009708737864
 > 22.482893450635387
 > 22.395326192794546
 > 22.136669874879694
Average (mean) 22.14499343386846

autoCacheQuery
Raw:
 > 20.408163265306122
 > 21.40077821011673
 > 21.215043394406944
 > 21.42161635832522
 > 21.42161635832522
Average (mean) 21.17344351729605

selfShadowingGetter_Cache
Raw:
 > 20.0381679389313
 > 20.192307692307693
 > 20.211742059672762
 > 20.23121387283237
 > 20.669291338582678
Average (mean) 20.26854458046536

selfShadowingGetter_NoCache
Raw:
 > 19.41747572815534
 > 19.398642095053347
 > 19.305019305019304
 > 19.398642095053347
 > 19.49317738791423
Average (mean) 19.40259132223911

noAutoQuery
Raw:
 > 5.405405405405405
 > 5.571030640668524
 > 5.58659217877095
 > 5.612722170252573
 > 5.591798695246971
Average (mean) 5.553509818068885

autoQuery
Raw:
 > 5.29567519858782
 > 5.504587155963303
 > 5.46448087431694
 > 5.509641873278237
 > 5.560704355885079
Average (mean) 5.467017891606276

Winner: noAutoCache
Compared with next highest (autoCache), it's:
46.22% faster
1.86 times as fast
0.27 order(s) of magnitude faster

Compared with the slowest (autoQuery), it's:
98.94% faster
94.21 times as fast
1.97 order(s) of magnitude faster


*/