Benchmark: Array.reduce vs for loop vs Array.forEach vs for of loop - 30

Script Preparation code:

//Create an array of 30 random intergers between 1 and 10000
var arrRandom = [];
for(var intCtr=0; intCtr<30; intCtr++) {
  arrRandom.push(Math.floor(Math.random() * Math.floor(10000)));
}

function reduceCallback(accum, curr) {
	return accum+curr;
}

function doReduce(pArray) {
	return pArray.reduce(reduceCallback);
}
function doForLoop(pArray) {
	var accum = 0;
	var arrLength = pArray.length;
	for(var intCtr=0; intCtr<arrLength; intCtr++) {
		accum += pArray[intCtr];
	}
	return accum;
}
function doForOfLoop(pArray) {
	var accum = 0;
	for(var value of pArray) {
		accum += value;
	}
	return accum;
}
function doForEach(pArray) {
	var accum = 0;
	pArray.forEach(function(item) {
		accum += item;
	});
}

Tests:

reduce
var redeuceResult=0; redeuceResult = doReduce(arrRandom);
for loop
var loopResult=0; loopResult = doForLoop(arrRandom);
forEach
var forEachResult=0 forEachResult = doForEach(arrRandom)
for of loop
var forOfResult=0 forOfResult = doForOfLoop(arrRandom)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce
for loop
forEach
for of loop

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its various components.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark that compares the performance of four different loop constructs: `Array.reduce`, `for` loop, `Array.forEach`, and `for...of` loop. The benchmark is designed to sum 1,000 random integers between 1 and 10,000 using each of these loops.

**Loop Constructs Compared**

The benchmark compares the following four loop constructs:

1. **Array.reduce**: This method uses a callback function to iterate over the array and accumulate the results.
2. **for` loop**: A traditional `for` loop is used to iterate over the array elements and sum them up.
3. **Array.forEach`: This method iterates over the array elements using a callback function, but it does not provide an accumulator parameter like `reduce`.
4. **for...of` loop**: This is a newer loop construct introduced in ECMAScript 2015 that allows iterating over arrays without using traditional indexing.

**Options Compared**

The benchmark compares these four options to determine which one performs best:

* **Pro and Cons of each approach:**
	+ `Array.reduce`: Pros: concise, efficient; Cons: requires callback function, can be slower due to array reversal.
	+ `for` loop: Pros: simple, familiar; Cons: more verbose, may involve indexing errors.
	+ `Array.forEach`: Pros: easy to read, modern syntax; Cons: lacks accumulator, may not be as efficient as `reduce`.
	+ `for...of` loop: Pros: concise, readable, and modern; Cons: relatively new, may not support older browsers or environments.
* **Other considerations:**
	+ The benchmark uses a large array of random integers to simulate real-world performance, making it more representative of actual use cases.
	+ The use of `Math.random()` ensures that the input data is unpredictable and may vary on different runs.

**Library Used**

There is no external library used in this benchmark. All four loop constructs are implemented using only built-in JavaScript functions and methods.

**Special JS Feature or Syntax**

The `for...of` loop is a relatively new feature introduced in ECMAScript 2015, also known as "iterators" or "generators". This syntax allows iterating over arrays without using traditional indexing, which can improve code readability and maintainability.

**Benchmark Results Interpretation**

Looking at the benchmark results, we see that:

* The `for` loop performs the best, with an average execution rate of 4.54 executions per second.
* The `Array.forEach` loop comes in second, with an average execution rate of 4.41 executions per second.
* The `Array.reduce` loop follows next, with an average execution rate of 1.33 executions per second.
* The `for...of` loop performs the worst, with an average execution rate of 0.84 executions per second.

Other alternatives for similar benchmarks include:

* Using a testing framework like Jest or Mocha to write and run tests
* Employing parallel processing techniques using Web Workers or async/await to speed up benchmarking
* Utilizing specialized JavaScript performance tools, such as jsperf or Benchmark.js

Please note that the actual results may vary depending on the specific environment, browser, or version of JavaScript being used.

Related benchmarks:

Array.reduce vs for loop vs Array.forEach vs for of loop - 30 (version: 0)

A test summing 1000 random numbers, 1 - 10000

Comparing performance of: reduce vs for loop vs forEach vs for of loop

Created: 7 years ago by: Guest

Jump to the latest result

reduce

for loop

forEach

for of loop

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):