Benchmark: Reduce to array - MeasureThat.net

Tests:

spread
const things = [1, 2, 3, 4]; const reduced = things.reduce((acc, thing) => { return [...acc, thing]; }, []);
push
const things = [1, 2, 3, 4]; const reduced = things.reduce((acc, thing) => { acc.push(thing); return acc; }, []);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
push

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and provide insights on the tested options.

**Benchmark Overview**

The benchmark measures the performance of two approaches for reducing an array in JavaScript: using `push` versus spreading the accumulator array with `...`.

**Options Compared**

There are two test cases:

1. **Spread**: This approach uses the spread operator (`...`) to create a new array and append elements to it.
```javascript
const reduced = things.reduce((acc, thing) => {
  return [...acc, thing];
}, []);
```
2. **Push**: This approach modifies the accumulator array by using `push` to add elements to it.

```javascript
const reduced = things.reduce((acc, thing) => {
  acc.push(thing);
  return acc;
}, []);
```

**Pros and Cons of Each Approach**

1. **Spread**:
	* Pros:
		+ Creates a new array, which can be more efficient if the original array is large.
		+ Avoids modifying the accumulator array, which can be beneficial for preserving data integrity.
	* Cons:
		+ Creates an unnecessary copy of the accumulator array, which can lead to increased memory usage.
2. **Push**:
	* Pros:
		+ Modifies the existing accumulator array, which can reduce memory allocation overhead.
	* Cons:
		+ Modifies the original array, which can have unintended consequences if the accumulator array is used elsewhere.

**Library and Special JS Features**

In this benchmark, there are no libraries used, but I'll mention that if any library was used, it would impact the performance results. Additionally, there's a special JS feature being tested: **Rest Parameter Syntax**, which is part of the ECMAScript 2015 (ES6) standard.

The Rest Parameter Syntax (`...`) allows you to create an array-like object from arguments, which is what happens in the `spread` approach. This syntax was introduced in ES6 and has since become a standard feature in modern JavaScript.

**Other Considerations**

* **Array Performance**: The benchmark focuses on reducing an array, but other operations like searching, filtering, or sorting would require different approaches.
* **Browser and Platform Variability**: The results are specific to Safari 13 on Mac OS X 10.14.6. Other browsers or platforms might have different performance characteristics.

**Alternatives**

If you were to write a similar benchmark for reducing an array in JavaScript, you could consider testing:

1. Using `Array.prototype.forEach()` with the `thisArg` parameter.
2. Utilizing Web Workers for parallel execution.
3. Examining the impact of array size on performance using different approaches (e.g., iterating over arrays vs. using `map()` or `filter()`).
4. Measuring performance with various data structures, such as objects or sets.

Feel free to ask if you have any further questions or need clarification!

Related benchmarks:

Reduce to array (version: 0)

Spread accumulator vs push

Comparing performance of: spread vs push

Created: 6 years ago by: Guest

Jump to the latest result

spread

push

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):