compare json serialization: default toJSON vs. asking for an additional .toString('hex') format

benchmark.js

var Benchmark = require('benchmark');

var suite = new Benchmark.Suite;

var obj1 = { food: Buffer('c0ffee', 'hex'), bar: 3 };

var obj2 = {
  'id': Buffer('eceb3ae8aee125e2', 'hex'),
  'secret': Buffer('281a885146ee216844d1ffd0d725ee714101548a1e6507f1a40fb2c2ae0c11f1', 'hex'),
  'name':'blah',
  'imageUri':'https://blah.example.com/img/logo@2x.png',
  'redirectUri':'https://blah.example.com/api/oauth',
  'whitelisted':true,
  'canGrant':false,
  'createdAt': Date.now()
}

function json(obj) {
  var seen = [];
  return JSON.stringify(obj, function filter(key, val) {
    if (typeof val === 'object' && val != null) {
      if (seen.indexOf(val) !== -1) {
        return '[Circular]';
      }
      seen.push(val);
    }
    return val;
  }, 0);
}

function json2(obj) {
  var seen = [];
  return JSON.stringify(obj, function filter(key, val) {
    if (Buffer.isBuffer(this[key])) {
      // `val` in this case is the toJSON result on Buffer, an array of 8-bit
      // integers. Instead, the hex format is more compact and just as useful.
      // A string value would not match the object check below, so return now.
      return this[key].toString('hex')
    }

    if (typeof val === 'object' && val != null) {
      if (seen.indexOf(val) !== -1) {
        return '[Circular]';
      }
      seen.push(val);
    }
    return val;
  }, 0);
}

suite
  .add('accept default toJSON() of buffer; simple object         ', function() {
    var str = json(obj1)
  })
  .add('convert again with toString("hex"); simple object        ', function() {
    var str = json(obj1)
  })
  .add('accept default toJSON() of buffer; more realistic object ', function() {
    var str = json(obj2)
  })
  .add('convert again with toString("hex"); more realistic object', function() {
    var str = json(obj2)
  })
  .on('cycle', function(event) {
    console.log(String(event.target));
  })
  .on('complete', function() {
    console.log('Fastest is ' + this.filter('fastest').pluck('name'));
  })
  .run({ 
    'async': true
  });