Benchmark: getOwnPropertyNames vs Object.keys - performance

Script Preparation code:

var obj = {
  $props : ['a','b','c'],
  a:1,
  b:2,
  c:3
}

Tests:

getOwnPropertyNames
const arr = Object.getOwnPropertyNames(obj); let n = 0; for (let i = 0; i < arr.length; i++) { const k = arr[i]; if (k.charAt(0) == '$') continue; n++; }
Object.keys
const arr = Object.keys(obj); let n = 0; for (let i = 0; i < arr.length; i++) { const k = arr[i]; if (k.charAt(0) == '$') continue; n++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getOwnPropertyNames
Object.keys

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:138.0) Gecko/20100101 Firefox/138.0

Browser/OS: Firefox 138 on Linux

View result in a separate tab

Test name	Executions per second
getOwnPropertyNames	30381512.0 Ops/sec
Object.keys	30031426.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Purpose**

The benchmark compares the performance of two approaches to get an array of property names from an object: `Object.keys()` and the `getOwnPropertyNames` method in combination with a manual filtering process.

**Options Compared**

Two options are compared:

1. **`Object.keys()`**: This method returns an array of a given object's own enumerable property names.
2. **`getOwnPropertyNames` + manual filtering**: The `getOwnPropertyNames` method returns an array of all property names, including non-enumerable ones. To filter out properties whose names start with `$`, the benchmark uses a manual loop to iterate over the array and skip those properties.

**Pros and Cons**

* **`Object.keys()`**:
	+ Pros: Simple, efficient, and widely supported.
	+ Cons: Excludes non-enumerable property names, which may be important in certain scenarios.
* **`getOwnPropertyNames` + manual filtering**:
	+ Pros: Includes all property names, including non-enumerable ones. The filtering process can be customized to suit specific use cases.
	+ Cons: More complex and computationally intensive due to the manual loop.

**Library**

The `Object.keys()` method is a built-in JavaScript method that is part of the ECMAScript standard. It's widely supported across different browsers and environments.

**Special JS Feature or Syntax**

This benchmark does not use any special JavaScript features or syntax beyond what's considered "standard" by the ECMAScript standard. However, it's worth noting that `getOwnPropertyNames` is a legacy method from older versions of JavaScript (pre-ES6), whereas `Object.keys()` is a modern method introduced in ES5.

**Other Alternatives**

If you need to get an array of property names and don't mind excluding non-enumerable ones, other alternatives might include:

* Using the `for...in` loop with a custom filtering process.
* Utilizing a library like Lodash or Underscore.js that provides utility functions for working with objects.
* Converting the object to an array using `Object.values()` and then filtering it.

Keep in mind that these alternatives may have different performance characteristics, trade-offs, or requirements depending on your specific use case.

Related benchmarks:

getOwnPropertyNames vs Object.keys - performance (version: 0)

Comparing performance of: getOwnPropertyNames vs Object.keys

Created: 3 years ago by: Guest

Jump to the latest result

getOwnPropertyNames

Object.keys

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):