Benchmark: Object.fromEntries vs reduce vs Map/reduce vs new Map

Script Preparation code:

var data = { ...Array.from(Array(10000).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() }), {});
Map (reduce)
Object.entries(data).reduce((acc, [k, v]) => { acc.set(k, v.toString()) return acc; }, new Map());
Map (constructor)
new Map(Object.entries(data))

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)
Map (reduce)
Map (constructor)

Fastest: N/A

Slowest: N/A

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/111.0.0.0 Safari/537.36

Browser/OS: Chrome 111 on Windows

View result in a separate tab

Test name	Executions per second
Object.fromEntries	93.4 Ops/sec
Reduce (reuse object)	1057.0 Ops/sec
Reduce (creating temporary objects)	22.9 Ops/sec
Map (reduce)	678.9 Ops/sec
Map (constructor)	811.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The benchmark is designed to compare the performance of four different approaches for creating and populating an object from an array:

1. `Object.fromEntries`
2. Reduce (creating temporary objects)
3. Map/reduce
4. New Map

**Options Compared**

Here's a brief overview of each option:

* **Object.fromEntries**: A modern JavaScript method introduced in ECMAScript 2015, which creates an object from key-value pairs passed as an array.
* **Reduce (reuse object)**: The `reduce` method is used with an initial value of an empty object. As the array is iterated over, each element's key-value pair is appended to the accumulator object.
* **Reduce (creating temporary objects)**: Similar to the previous option, but a new object is created on each iteration for each key-value pair.
* **Map/reduce**: A Map data structure is used to store the key-value pairs. The `reduce` method is then applied to create an object from the map's entries.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Object.fromEntries**:
	+ Pros: Fast, concise, and modern.
	+ Cons: May not be supported in older browsers or environments.
* **Reduce (reuse object)**:
	+ Pros: Efficient use of memory and CPU resources.
	+ Cons: Can lead to performance issues if the accumulator object is too large.
* **Reduce (creating temporary objects)**:
	+ Pros: Simple implementation, easy to understand.
	+ Cons: Creates multiple objects on each iteration, which can be inefficient.
* **Map/reduce**:
	+ Pros: Allows for parallel processing and caching of intermediate results.
	+ Cons: May require more memory and CPU resources.

**Library Usage**

In the benchmark code, a library is used to create an array with 10,000 elements. The `Array.from()` method is used to create an array from an iterable object (in this case, an array with numbers).

No specific libraries are used for the object creation or iteration logic.

**Special JavaScript Feature/Syntax**

The benchmark uses modern JavaScript features such as:

* **Template literals**: Used in the `reduce` methods to create a new object.
* **Arrow functions**: Used in the `reduce` methods and the `Object.entries()` method.
* **Modern data structures**: Maps are used instead of traditional objects.

**Alternatives**

Other alternatives for creating an object from an array include:

* Using a simple loop to iterate over the array and create the object manually.
* Utilizing a library like Lodash or Underscore.js, which provide various functions for working with arrays and objects.
* Employing a different data structure, such as a JSON array or a CSV file.

Keep in mind that the choice of approach depends on the specific requirements and constraints of your project.

Related benchmarks:

Object.fromEntries vs reduce vs Map/reduce vs new Map (version: 0)

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

Created: one year ago by: Guest

Jump to the latest result

Object.fromEntries

Reduce (reuse object)

Reduce (creating temporary objects)

Map (reduce)

Map (constructor)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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