Benchmarking how much faster it is to null a property of a complex object versus deleting that property in JavaScript

benchmark-complex-object-delete-vs-assign.js

var Benchmark = require('benchmark');

function complete() {
  console.log(String(this));
}

var objDeleteBenchmark = new Benchmark('Object#delete-property', {
  setup: function() {
    var obj = {
      foo: {
        bar: {
          baz: 'baz',
          qux: 'qux',
          bool: false
        }
      },
      foo2: {
        bar2: {
          baz: false
        }
      }
    };
  },
  fn: function() { delete obj.foo.bar; }
});

var nullPropertyBenchmark = new Benchmark('Object#null-property', {
  setup: function() {
    var obj = {
      foo: {
        bar: {
          baz: 'baz',
          qux: 'qux',
          bool: false
        }
      },
      foo2: {
        bar2: {
          baz: false
        }
      }
    };
  },
  fn: function() { obj.foo.bar = null; }
});

objDeleteBenchmark.run({ 'async': true }).on('complete', complete);
nullPropertyBenchmark.run({ 'async': true }).on('complete', complete);

$ node index.js
Object#null-property x 782,807,915 ops/sec ±1.17% (89 runs sampled)
Object#delete-property x 15,986,585 ops/sec ±0.96% (94 runs sampled)