Deep Copy vs JSON Stringify / JSON Parse

JavaScript performance comparison

Revision 21 of this test case created by

Preparation code

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.4.0/lodash.js"></script>

      
<script>
Benchmark.prototype.setup = function() {
  function recursiveDeepCopy(o) {
    var newO,
      i;
  
    if (typeof o !== 'object') {
      return o;
    }
    if (!o) {
      return o;
    }
  
    if ('[object Array]' === Object.prototype.toString.apply(o)) {
      newO = [];
      for (i = 0; i < o.length; i += 1) {
        newO[i] = recursiveDeepCopy(o[i]);
      }
      return newO;
    }
  
    newO = {};
    for (i in o) {
      if (o.hasOwnProperty(i)) {
        newO[i] = recursiveDeepCopy(o[i]);
      }
    }
    return newO;
  }
  
  function recursiveDeepCopyNoTouch(o) {
    var i;
  
    if (typeof o !== 'object') {
      return o;
    }
    if (!o) {
      return o;
    }
  
    if ('[object Array]' === Object.prototype.toString.apply(o)) {
      for (i = 0; i < o.length; i += 1) {
        recursiveDeepCopy(o[i]);
      }
      return o;
    }
  
    for (i in o) {
      if (o.hasOwnProperty(i)) {
        recursiveDeepCopy(o[i]);
      }
    }
    return o;
  }
  
  function deepCopy(o) {
    var copy = o,
      k;
  
    if (o && typeof o === 'object') {
      copy = Object.prototype.toString.call(o) === '[object Array]' ? [] : {};
      for (k in o) {
        copy[k] = deepCopy(o[k]);
      }
    }
  
    return copy;
  }
  
  function clone(obj) {
    if (obj == null || typeof(obj) != 'object')
      return obj;
  
    var temp = new obj.constructor();
    for (var key in obj)
      temp[key] = clone(obj[key]);
  
    return temp;
  }
  
  var uc = {
    "list": {
      "0oVwOM": {
        "id": "0oVwOM",
        "parent": "pTlmbh",
        "name": "New node",
        "created_at": 1384289621
      },
      "aHxe8k": {
        "id": "aHxe8k",
        "parent": "Fhs2hL",
        "name": "hjkhjkhjk",
        "created_at": 1384354593
      },
      "Fhs2hL": {
        "id": "Fhs2hL",
        "parent": "root",
        "name": "test",
        "created_at": 1383403881
      },
      "HYPSgv": {
        "id": "HYPSgv",
        "parent": "0oVwOM",
        "name": "New node",
        "created_at": 1384342657
      },
      "osFIMf": {
        "id": "osFIMf",
        "parent": "root",
        "name": "New node",
        "created_at": 1384354584
      },
      "PsovXE": {
        "id": "PsovXE",
        "parent": "root",
        "name": "hjkhjkhjk",
        "created_at": 1384354589
      },
      "pTlmbh": {
        "id": "pTlmbh",
        "parent": "Fhs2hL",
        "name": "New node",
        "created_at": 1384289277
      },
      "RbXhdJ": {
        "id": "RbXhdJ",
        "parent": "root",
        "name": "empty",
        "created_at": 1384359806
      }
    },
    "maps": {
      "parent": {
        "pTlmbh": {
          "0oVwOM": {
            "id": "0oVwOM",
            "parent": "pTlmbh",
            "name": "New node",
            "created_at": 1384289621
          }
        },
        "Fhs2hL": {
          "aHxe8k": {
            "id": "aHxe8k",
            "parent": "Fhs2hL",
            "name": "hjkhjkhjk",
            "created_at": 1384354593
          },
          "pTlmbh": {
            "id": "pTlmbh",
            "parent": "Fhs2hL",
            "name": "New node",
            "created_at": 1384289277
          }
        },
        "root": {
          "Fhs2hL": {
            "id": "Fhs2hL",
            "parent": "root",
            "name": "test",
            "created_at": 1383403881
          },
          "osFIMf": {
            "id": "osFIMf",
            "parent": "root",
            "name": "New node",
            "created_at": 1384354584
          },
          "PsovXE": {
            "id": "PsovXE",
            "parent": "root",
            "name": "hjkhjkhjk",
            "created_at": 1384354589
          },
          "RbXhdJ": {
            "id": "RbXhdJ",
            "parent": "root",
            "name": "empty",
            "created_at": 1384359806
          }
        },
        "0oVwOM": {
          "HYPSgv": {
            "id": "HYPSgv",
            "parent": "0oVwOM",
            "name": "New node",
            "created_at": 1384342657
          }
        }
      },
      "path": [
        ["Fhs2hL"],
        ["Fhs2hL", "aHxe8k"],
        ["Fhs2hL", "pTlmbh"],
        ["Fhs2hL", "pTlmbh", "0oVwOM"],
        ["Fhs2hL", "pTlmbh", "0oVwOM", "HYPSgv"],
        ["osFIMf"],
        ["PsovXE"],
        ["RbXhdJ"]
      ]
    }
  };
  var isPlainObject = function(obj) {
      return obj != null && typeof obj === 'object'
          && !Array.isArray(obj) && obj.constructor === Object;
  }
  
  var trackable = function(o, stats, prependKey) {
    var out, key;
  
    var stats = stats || [];
    var prependKey = prependKey || '';
  
    if (typeof o !== 'object') {
      return o;
    }
    if (!o) {
      return o;
    }
  
    if ('[object Array]' === Object.prototype.toString.apply(o)) {
      // ignore arrays
      return JSON.parse(JSON.stringify(o));
    }
  
    out = {};
    var each = function(v, k) {
      Object.defineProperty(out, k, {
        enumerable: true,
        get: function() {
          stats.push(catKey);
          return v;
        }
      });
    };
    for (key in o) {
      if (o.hasOwnProperty(key)) {
        var catKey = (prependKey ? prependKey + '.' : '') + key;
        var value = trackable(o[key], stats, catKey);
        each(value, key);
      }
    }
  
    if (!prependKey) {
      Object.defineProperty(out, 'stats', {
        enumerable: true,
        value: function() {
          return stats;
        }
      });
    }
  
    return out;
  };
  
  function recursive(obj) {
    var clone, i;
  
    if (typeof obj !== 'object' || !obj)
      return obj;
  
    if ('[object Array]' === Object.prototype.toString.apply(obj)) {
      clone = [];
      var len = obj.length;
      for (i = 0; i < len; i++)
        clone[i] = recursive(obj[i]);
      return clone;
    }
  
    clone = {};
    for (i in obj)
      if (obj.hasOwnProperty(i))
        clone[i] = recursive(obj[i]);
    return clone;
  }

};
</script>

Preparation code output

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
recurse only - no touch
var bes = recursiveDeepCopyNoTouch(uc);
pending…
lodash
var bes = _.cloneDeep(uc);
pending…
trackable copy
var bes = trackable(uc);
pending…
$
var bes = jQuery.extend(true, {}, uc);
pending…
recursive
var bes = recursiveDeepCopy(uc);
pending…
JSON Stringify / JSON Parse
var bes = JSON.parse(JSON.stringify(uc))
pending…
clone
var bes = clone(uc);
pending…
Deep Copy
var bes = deepCopy(uc)
pending…

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Revisions

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