Benchmark: Sum an array2 - MeasureThat.net

Script Preparation code:

var arr = [];
for (let j=0; j < 1000000; j++ ) {
  arr.push(j);
}

Tests:

Reduce
const r = arr.reduce( (p,c) => p+c, 0);
for..of
let r=0; for (v of arr) { r+=v; }
for
let r = 0; const l = arr.length; for (var i=0; i < l; i++ ) { r += arr[i]; }
foreach
let r = 0; arr.forEach( (v) => r += v );
for..of with const
let r=0; for (const v of arr) { r+=v; }
for again
let r = 0, i=0; const l = arr.length; for (;i < l;) { r += arr[i++]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reduce
for..of
for
foreach
for..of with const
for again

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.104 Safari/537.36

Browser/OS: Chrome 88 on Windows

View result in a separate tab

Test name	Executions per second
Reduce	50.7 Ops/sec
for..of	1.9 Ops/sec
for	8.3 Ops/sec
foreach	31.6 Ops/sec
for..of with const	751.6 Ops/sec
for again	8.2 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Preparation Code**

The script preparation code creates an array `arr` with 1,000,000 elements, each containing a sequential number from 0 to 999,999. This is done using a `for` loop that pushes each number onto the array.

**Test Cases**

The benchmark consists of six test cases, each measuring the performance of a different JavaScript iteration method:

1. `Reduce`: Uses the `reduce()` method to sum up all elements in the array.
2. `for..of with const`: Uses a `for...of` loop with `const` declaration to iterate over the array and sum up its elements.
3. `foreach`: Uses the `forEach()` method to iterate over the array and sum up its elements.
4. `for`: Uses a traditional `for` loop to iterate over the array and sum up its elements.
5. `for again`: Similar to the previous one, but uses an index variable (`i`) instead of a direct reference to the element.
6. `for..of`: Another `for...of` loop without `const`, used for comparison.

**Library Usage**

None of these test cases explicitly use any libraries or external dependencies.

**JS Features/Syntax**

The only notable feature is the use of `const` declaration in some test cases (`for..of with const` and another `for...of`). This is a relatively modern JavaScript feature that declares variables as constant, ensuring they cannot be reassigned. Its usage helps prevent potential performance issues by avoiding unnecessary reassignments.

**Options Compared**

The benchmark compares the performance of six different iteration methods:

1. **Reduce()**: A built-in method for reducing an array to a single value.
2. **for...of with const**: An improved version of traditional `for` loops, providing better performance and readability.
3. **forEach()**: Another iteration method that can be used for summing up elements in an array.
4. **Traditional for loop**: A basic iteration method using a variable index.
5. **for again**: A variation of the traditional `for` loop with an additional index variable (`i`).
6. **for...of (non-const)**: Another iteration method similar to `for...of with const`, but without declaring variables as constant.

**Pros and Cons**

Here's a brief summary:

* **Reduce()**: Simple, efficient, and widely supported. However, it may not be the best choice for large arrays or performance-critical applications.
* **for...of with const**: Offers better performance and readability compared to traditional `for` loops. It also ensures variables are not reassigned, which can prevent performance issues in some cases.
* **forEach()**: Similar to `for...of`, but may have additional overhead due to its method call.
* **Traditional for loop**: The most basic iteration method, but can be slower and more error-prone compared to the others.
* **for again**: A variation of traditional `for` loops with an additional index variable. It may not offer significant performance benefits over the other options.

**Other Alternatives**

Some alternatives to these iteration methods include:

* Using `Array.prototype.map()` or `Array.prototype.every()` to achieve similar results.
* Leveraging parallel processing libraries like Web Workers to speed up computationally intensive operations.
* Optimizing the algorithm itself, if possible, to reduce overhead and improve performance.

Keep in mind that the best approach will depend on the specific use case and requirements.

Related benchmarks:

Sum an array2 (version: 2)

Comparing performance of: Reduce vs for..of vs for vs foreach vs for..of with const vs for again

Created: 3 years ago by: Registered User

Jump to the latest result

Reduce

for..of

for

foreach

for..of with const

for again

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):