Benchmark: Object.fromEntries vs reduce 123

Script Preparation code:

var data = { ...Array.from(Array(20).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

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36

Browser/OS: Chrome 127 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Object.fromEntries	203014.4 Ops/sec
Reduce (reuse object)	1137233.9 Ops/sec
Reduce (creating temporary objects)	537297.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what is tested in this benchmark.

**Benchmark Definition**

The benchmark tests two approaches to create an object from an array of key-value pairs: `Object.fromEntries` and the `reduce()` method with two variations:

1. **Reuse Object**: The accumulator is reused as a new object on each iteration, where only the value part is assigned.
2. **Creating Temporary Objects**: A new object is created on each iteration.

**Options Compared**

The benchmark compares the performance of these three approaches:

1. `Object.fromEntries`: creates an object from an array of key-value pairs by iterating over the array and adding properties to the resulting object.
2. **Reuse Object**: uses the accumulator as a new object, only assigning the value part on each iteration.
3. **Creating Temporary Objects**: creates a new object on each iteration, where only the key-value pair is assigned.

**Pros and Cons of Each Approach**

1. `Object.fromEntries`:
	* Pros: concise syntax, easy to read and maintain.
	* Cons: may incur overhead due to array-to-object conversion.
2. **Reuse Object**:
	* Pros: potentially more efficient by reusing the accumulator object.
	* Cons: requires careful handling of shared properties and potential memory leaks.
3. **Creating Temporary Objects**:
	* Pros: avoids potential issues with shared objects, but may incur overhead due to frequent object creation.
	* Cons: can lead to performance degradation due to excessive temporary objects.

**Library/Function Usage**

The benchmark uses the `reduce()` method, which is a built-in JavaScript function. The `Object.fromEntries()` function was introduced in ECMAScript 2015 (ES6) and provides a more concise way of creating an object from an array of key-value pairs.

**Special JS Features/Syntax**

There are no specific JavaScript features or syntax mentioned in the benchmark that require special explanation.

**Other Considerations**

When choosing between these approaches, consider the following:

* If readability and maintainability are more important than performance, `Object.fromEntries` might be a better choice.
* If performance is critical and you're dealing with large datasets, **Creating Temporary Objects** or **Reuse Object** might be more suitable.
* Be cautious when using **Reuse Object**, as it can lead to memory leaks if not handled carefully.

**Alternative Approaches**

Other approaches to create an object from an array of key-value pairs could include:

1. Using `Array.prototype.reduce()` with a custom accumulator object.
2. Using a library like Lodash or Underscore.js, which provides utility functions for creating objects from arrays.
3. Using a library like Ramda, which provides functional programming utilities, including functions for creating objects from arrays.

These alternative approaches might offer different trade-offs in terms of performance, readability, and maintainability.

Related benchmarks:

Object.fromEntries vs reduce 123 (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>

Fastest: N/A

Slowest: N/A

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