Benchmark: Object.fromEntries vs reduce 2.1

Script Preparation code:

var data = [...Array(10000)].map((_, i) => [i, i]);

Tests:

Object.fromEntries
Object.fromEntries(data);
Reduce (mutate)
data.reduce((acc, [k, v]) => { acc[k] = v; return acc; }, {});
Reduce (spread)
data.reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.fromEntries
Reduce (mutate)
Reduce (spread)

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark is comparing three approaches to create an object from an array of key-value pairs:

1. `Object.fromEntries(data)`
2. `data.reduce((acc, [k, v]) => {\r\n  acc[k] = v;\r\n  return acc;\r\n}, {})`
3. `data.reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {})`

**Options Comparison**

The three options are being compared in terms of performance, specifically the number of executions per second.

* `Object.fromEntries(data)`: This method is a modern addition to JavaScript (introduced in ECMAScript 2015), which creates an object from an array of key-value pairs. It's designed to be fast and efficient.
* `data.reduce((acc, [k, v]) => {\r\n  acc[k] = v;\r\n  return acc;\r\n}, {})`: This method uses the Array.prototype.reduce() method to iterate over the array and create an object. The callback function takes each key-value pair from the array and adds it to the accumulator object.
* `data.reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {})`: This method is similar to the previous one but uses spread notation (`{ ...acc, [k]: v }`) to create a new object for each iteration. The callback function takes each key-value pair from the array and adds it to the accumulator object.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* `Object.fromEntries(data)`:
	+ Pros: Fast, efficient, modern, and widely supported.
	+ Cons: May not be as flexible or customizable as other approaches.
* `data.reduce((acc, [k, v]) => {\r\n  acc[k] = v;\r\n  return acc;\r\n}, {})`:
	+ Pros: Flexible, customizable, and well-established.
	+ Cons: Can be slower than modern methods like `Object.fromEntries()` due to the need for manual iteration.
* `data.reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {})`:
	+ Pros: Similar to the previous approach but with spread notation, which can make the code more concise and readable.
	+ Cons: Still requires manual iteration and may be slower than modern methods.

**Library and Special JS Features**

There are no libraries being used in this benchmark. However, `Object.fromEntries()` is a special feature introduced in ECMAScript 2015, making it a modern JavaScript feature that's widely supported across different browsers and environments.

**Other Alternatives**

If you're looking for alternative approaches to create an object from an array of key-value pairs, some other options include:

* Using the Array.prototype.forEach() method with an arrow function or a regular function to iterate over the array.
* Using a library like Lodash (which includes a `mapObject` function) or Moment.js (which includes a `fromEntries` function).
* Creating a custom function using a for...of loop or a while loop to iterate over the array.

Keep in mind that these alternatives may have different performance characteristics and might require more manual effort to implement.

Related benchmarks:

Object.fromEntries vs reduce 2.1 (version: 0)

Comparing performance of: Object.fromEntries vs Reduce (mutate) vs Reduce (spread)

Created: 4 years ago by: Guest

Jump to the latest result

Object.fromEntries

Reduce (mutate)

Reduce (spread)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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