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

benchmark-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'}; },
  fn: function() { delete obj.foo; }
});

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

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

$ node index.js
Object#delete-property x 14,632,549 ops/sec ±2.00% (82 runs sampled)
Object#null-property x 1,069,853,337 ops/sec ±1.92% (85 runs sampled)

• In this simplistic test, assigning to null is about 73 times faster than deleting a property.
• In 1% of 1ms you can delete a property from an object 146 times.

Whether it's worth it to null out properties as an alternative to deletion is left as an exercise to the reader.

Same test using a more complex object

Good job