Benchmark: test1: for...in vs Object.keys().forEach();

Tests:

for in
const ob = Array.from({ length: 100 }, (_, i) => i).reduce((acc, item) => { const value = Math.random(); const key = btoa(value.toString()); acc[key] = value; return acc; }, {}); for(const key in ob) { ob[key] += 1; };
object.keys
const ob = Array.from({ length: 100 }, (_, i) => i).reduce((acc, item) => { const value = Math.random(); const key = btoa(value.toString()); acc[key] = value; return acc; }, {}); Object.keys(ob).forEach(key => { ob[key] += 1; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for in
object.keys

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what is being tested.

**Benchmark Overview**

The benchmark compares two approaches to incrementing values in an object:

1. **For-in loop**: This approach uses a traditional `for-in` loop to iterate over the object's properties.
2. **Object.keys().forEach()**: This approach uses the `Object.keys()` method to get an array of the object's property names and then iterates over it using the `.forEach()` method.

**Options Compared**

The benchmark is comparing two options:

* For-in loop: This approach uses a traditional `for-in` loop, which iterates over the object's properties based on their property names.
* Object.keys().forEach(): This approach uses the `Object.keys()` method to get an array of the object's property names and then iterates over it using the `.forEach()` method.

**Pros and Cons**

* For-in loop:
	+ Pros: Can be more readable and intuitive for some developers, especially when working with legacy code.
	+ Cons: Can be slower due to the overhead of iterating over property names, and may not be as efficient in modern JavaScript engines.
* Object.keys().forEach():
	+ Pros: Can be faster and more efficient than the traditional `for-in` loop, especially for large objects. It also avoids the overhead of iterating over property names.
	+ Cons: May require additional imports or setup to work with all browsers.

**Library Usage**

The benchmark uses the **`Array.from()`** method, which is a modern JavaScript method that creates an array from an iterable source.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in this benchmark. It only uses standard JavaScript methods and variables.

**Other Alternatives**

If you want to compare these two approaches without using `Object.keys()`, you could also use:

* A traditional `for` loop: `for (const key in ob) { ... }`
* The `.entries()` method on the object itself: `for (const [key, value] of Object.entries(ob)) { ... }`

Keep in mind that these alternatives may not be as efficient or readable as the `Object.keys().forEach()` approach.

**Benchmark Preparation Code**

The benchmark preparation code is empty, which means it's up to the user to provide the necessary setup for their test case.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.89 Safari/537.36

Browser/OS: Chrome 84 on Mac OS X 10.15.5

View result in a separate tab

Test name	Executions per second
for in	3252.8 Ops/sec
object.keys	3670.4 Ops/sec

Related benchmarks:

test1: for...in vs Object.keys().forEach(); (version: 0)

Comparing performance of: for in vs object.keys

Created: 4 years ago by: Guest

Jump to the latest result

for in

object.keys

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):