Benchmark: Object.keys vs Object.values creation

Script Preparation code:

var obj = new Object()
var keys = (new Array(10000)).fill(0).map((x, i) => { return i + 1 })
keys.forEach((x) => { obj['prop' + x] = x })

Tests:

Object keys
const keys = Object.keys(obj); for (let j1 = 0; j1 < keys.length; j1++) { const key = keys[ j1 ]; const value = obj[ key ]; const result = key + value; }
Object entries
const entries = Object.entries(obj); for (let j1 = 0; j1 < entries.length; j1++) { const entry = entries[ j1 ]; const key = entry[0]; const value = entry[1]; const result = key + value; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object keys
Object entries

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser/OS: Chrome 103 on Windows

View result in a separate tab

Test name	Executions per second
Object keys	704.7 Ops/sec
Object entries	484.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The benchmark measures the performance difference between two approaches:

1. `Object.keys(obj)`
2. `Object.entries(obj)`

**Script Preparation Code**

The script creates an object with 10,000 properties using a simple loop:
```javascript
var obj = new Object();
var keys = (new Array(10000)).fill(0).map((x, i) => { return i + 1 });
keys.forEach((x) => { obj['prop' + x] = x; });
```
This script prepares the object and its key array before running the benchmark.

**Html Preparation Code**

There is no HTML preparation code provided in this benchmark definition.

**Options Compared**

The two options being compared are:

* `Object.keys(obj)`
* `Object.entries(obj)`

These methods return different data structures that can be used to access an object's properties.

**Pros and Cons of Each Approach**

1. **`Object.keys(obj)`**
	* Pros:
		+ More lightweight, as it only returns an array of property names.
		+ May be faster for small objects.
	* Cons:
		+ Returns a live array, which means it can change if the object is modified while iterating over it.
		+ May not be suitable for large objects due to memory constraints.
2. **`Object.entries(obj)`**
	* Pros:
		+ Returns an array of key-value pairs, which can make it easier to work with data.
		+ Less prone to issues with live arrays.
	* Cons:
		+ More heavyweight, as it returns a dense array of objects.
		+ May be slower for very large objects.

**Library**

In this benchmark, the `Object` library is being tested. The `Object` library provides various methods for working with objects, such as accessing properties using keys or iterating over an object's properties.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax used in this benchmark.

**Other Alternatives**

If you're interested in exploring other alternatives, here are a few:

* `Object.getOwnPropertyNames(obj)`: Similar to `Object.keys(obj)`, but also returns inherited property names.
* `Object.keys(obj).map(key => obj[key])`: Another way to use `Object.keys(obj)` to access properties.
* `Object.entries(obj).map(([key, value]) => key + value)`: A way to process the key-value pairs returned by `Object.entries(obj)`.

Keep in mind that these alternatives may have different performance characteristics or trade-offs compared to the original benchmark.

Related benchmarks:

Object.keys vs Object.values creation (version: 0)

Comparing performance of: Object keys vs Object entries

Created: 2 years ago by: Guest

Jump to the latest result

Object keys

Object entries

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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