Benchmark: test js count - MeasureThat.net

Script Preparation code:

var arr = [5, 5, 5, 2, 2, 2, 2, 2, 9, 4, 5, 5, 5, 2, 2, 2, 2, 2, 9, 4, 5, 5, 5, 2, 2, 2, 2, 2, 9, 4];

Tests:

for
const counts = {}; for (const num of arr) { counts[num] = counts[num] ? counts[num] + 1 : 1; }
reduce
arr.reduce(function (acc, curr) { return acc[curr] ? ++acc[curr] : acc[curr] = 1, acc }, {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

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

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

**What is being tested?**

MeasureThat.net is testing two different approaches to count the occurrences of each number in an array: `for` loop and `reduce()` method.

**Options compared**

The `for` loop approach iterates over the array using a traditional `for` loop, incrementing a counter for each element. The `reduce()` method, on the other hand, uses the Array.prototype.reduce() method to accumulate the counts in an object.

**Pros and Cons of each approach:**

* **For Loop Approach**
	+ Pros:
		- Easy to understand and implement.
		- Suitable for small arrays or simple cases.
	+ Cons:
		- Can be slower than the `reduce()` method, especially for large arrays.
		- More memory-intensive due to the use of a separate counter variable.
* **Reduce() Method Approach**
	+ Pros:
		- Generally faster and more efficient than the `for` loop approach.
		- Less memory-intensive since it only uses an object to store the counts.
	+ Cons:
		- Requires understanding of the `reduce()` method syntax, which can be unfamiliar to some developers.
		- May have performance issues if the array is very large or if the reduce function is not implemented correctly.

**Library and its purpose**

In this benchmark, no specific library is used. However, it's worth noting that the `reduce()` method is a built-in JavaScript method that was introduced in ECMAScript 2011 (ES6). It provides a concise way to accumulate values in an accumulator object.

**Special JS feature or syntax**

No special features or syntax are being tested in this benchmark. The code uses standard JavaScript syntax and does not rely on any advanced features like async/await, Promises, or async/async functions.

**Other alternatives**

If the `for` loop approach were not used, alternative approaches could include:

* Using the `forEach()` method with a callback function to iterate over the array.
* Using the `map()` method in combination with the `reduce()` method to achieve similar results.
* Using a library like Lodash or Ramda for more concise and expressive code.

However, it's worth noting that these alternatives may not provide significant performance improvements over the `for` loop approach for small to medium-sized arrays.

Related benchmarks:

test js count (version: 0)

Comparing performance of: for vs reduce

Created: 2 years ago by: Guest

Jump to the latest result

for

reduce

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):