Benchmark: Object.fromEntries on array vs reduce on array vs reduce(reuse object)

Script Preparation code:

var data = Array.from(Array(10000).keys());

Tests:

Reduce(reuse)
data.reduce((acc, value) => { acc[value] = value.toString(); return acc; }, {});
Reduce
data.reduce((acc, value) => ({ ...acc, [value]: value.toString() }), {});
Object.fromEntries
Object.fromEntries(data.map((value) => [value, value.toString()]));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reduce(reuse)
Reduce
Object.fromEntries

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser/OS: Chrome 103 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Reduce(reuse)	4827.6 Ops/sec
Reduce	61.2 Ops/sec
Object.fromEntries	1265.6 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided benchmark compares the performance of three different approaches to create an object from an array:

1. `Object.fromEntries`: This method takes an iterable (in this case, an array) and converts it into an object using the entries() method.
2. `Array.prototype.reduce()`: This method applies a reduction function to each element in the array, accumulating a result.

**Approach Comparison**

The benchmark tests three variations of these approaches:

1. **Reduce(reuse)**: This approach uses `reduce()` on the same array multiple times to build up an object, but with some optimizations (see below).
2. **Reduce**: This is the standard implementation of `Array.prototype.reduce()`, which accumulates a result by applying a reduction function to each element in the array.
3. **Object.fromEntries**: This method directly converts the array into an object using entries(), bypassing the need for a reduction function.

**Pros and Cons**

1. **Reduce(reuse)**:
	* Pros: Can be optimized for performance, as it only needs to iterate through the array once (initial pass), and subsequent passes can reuse some of the intermediate results.
	* Cons: Requires more complex code, and may not be as readable or maintainable as other approaches.
2. **Reduce**:
	* Pros: Standard implementation, widely supported, and easy to understand and implement.
	* Cons: May require additional memory for the accumulator object.
3. **Object.fromEntries**:
	* Pros: Simple, efficient, and widely supported (since it's a standard method).
	* Cons: Limited control over the resulting object structure.

**Libraries and Features**

There are no libraries involved in this benchmark. However, some JavaScript features like `Array.prototype.reduce()` and `Object.fromEntries()` rely on ECMAScript 2015+ syntax.

**Other Considerations**

To optimize Reduce(reuse), you can use techniques like:

* Reusing the accumulator object
* Using a more efficient reduction algorithm (e.g., using `reduceRight()` or implementing a custom iterator)
* Minimizing memory allocations and deallocations

Keep in mind that these optimizations may add complexity to the code, so it's essential to weigh the benefits against readability and maintainability.

**Alternatives**

If you need alternative approaches for creating an object from an array, consider:

1. `Array.prototype.map()` + `Object.fromEntries()`: This approach is similar to Reduce(reuse) but uses a more traditional map-reduce pattern.
2. `Array.prototype.forEach()` + `Object.assign()`: Another variation that uses the standard foreach method and Object.assign to accumulate results.

These alternatives may have different performance characteristics, so it's essential to test them in your specific use case.

Related benchmarks:

Object.fromEntries on array vs reduce on array vs reduce(reuse object) (version: 0)

Comparing performance of: Reduce(reuse) vs Reduce vs Object.fromEntries

Created: 2 years ago by: Guest

Jump to the latest result

Reduce(reuse)

Reduce

Object.fromEntries

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):