Benchmark: Object.fromEntries vs reduce 100000

Script Preparation code:

var data = { ...Array.from(Array(100000).keys()) };

Tests:

Object.fromEntries
Object.fromEntries(Object.entries(data).map((key, value) => [key, value]));
Reduce (reuse object)
Object.entries(data).reduce((acc, [k, v]) => { acc[k] = v.toString(); return acc; }, {});
Reduce (creating temporary objects)
Object.entries(data).reduce((acc, [k, v]) => ({ ...acc, [k]: v.toString() }), {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.fromEntries
Reduce (reuse object)
Reduce (creating temporary objects)

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

**Overview**

The provided benchmark measures the performance of two approaches to create an object from key-value pairs: `Object.fromEntries` and `reduce`. The benchmark is designed to test which approach is faster on a large dataset.

**Benchmark Definition**

The benchmark definition in JSON format consists of:

* A name for the benchmark
* An optional description (empty in this case)
* Script preparation code: This code creates an array of 100,000 keys using `Array.from(Array(100000).keys())` and assigns it to a variable named `data`. The purpose of this script is to provide a large dataset for testing.
* Html preparation code: There is no HTML preparation code provided (empty in this case).

**Individual Test Cases**

The benchmark has three test cases, each with a different approach:

1. **Object.fromEntries**: This approach uses the `Object.fromEntries` method to create an object from key-value pairs.
2. **Reduce (reuse object)**: This approach uses the `reduce` method on the `data` array to iterate over its elements and create a new object. The temporary objects created during iteration are not discarded, which may lead to higher memory usage compared to other approaches.
3. **Reduce (creating temporary objects)**: This approach is similar to the previous one but creates new temporary objects for each key-value pair, resulting in more memory allocation and garbage collection overhead.

**Library and Syntax**

The `Object.fromEntries` method was introduced in ECMAScript 2015 (ES6) as a way to create an object from key-value pairs. It is implemented by most modern browsers and Node.js environments.

**Pros and Cons of Each Approach**

1. **Object.fromEntries**:
	* Pros: Efficient, fast, and concise.
	* Cons: May not be supported in older browsers or environments that do not implement ES6+ features.
2. **Reduce (reuse object)**:
	* Pros: Can be more efficient than creating a new object for each key-value pair, especially when dealing with large datasets.
	* Cons: Creates temporary objects during iteration, leading to higher memory usage and potential garbage collection overhead.
3. **Reduce (creating temporary objects)**:
	* Pros: More concise and may be preferred by some developers due to its simplicity.
	* Cons: Results in more memory allocation and garbage collection overhead compared to the reuse approach.

**Other Alternatives**

In addition to the three approaches mentioned above, other methods can be used to create an object from key-value pairs:

* Using `Array.prototype.reduce()` with a custom callback function.
* Using a library like Lodash's `fromPairs` method.
* Using a simple loop and direct property assignment.

However, these alternatives may not provide the same level of efficiency as `Object.fromEntries`, especially for large datasets.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Browser/OS: Chrome 108 on Windows

View result in a separate tab

Test name	Executions per second
Object.fromEntries	13.4 Ops/sec
Reduce (reuse object)	45.5 Ops/sec
Reduce (creating temporary objects)	0.1 Ops/sec

Related benchmarks:

Object.fromEntries vs reduce 100000 (version: 0)

Comparing performance of: Object.fromEntries vs Reduce (reuse object) vs Reduce (creating temporary objects)

Created: one year ago by: Guest

Jump to the latest result

Object.fromEntries

Reduce (reuse object)

Reduce (creating temporary objects)

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):