Benchmark: Array.reduce vs for loop vs Array.forEach vs decrement while

Script Preparation code:

// Create an array of 1000 random intergers between 1 and 10000
var arrRandom = [];
for(var intCtr=0; intCtr<1000; intCtr++) {
  arrRandom.push(Math.floor(Math.random() * Math.floor(10000)));
}

function reduceCallback(accum, curr) {
	return accum+curr;
}

function doRedeuce(pArray) {
	return pArray.reduce(reduceCallback);
}
function doLoop(pArray) {
	var accum = 0;
	for(var intCtr=0; intCtr<pArray.length; intCtr++) {
		accum += pArray[intCtr];
	}
	return accum;
}
function decrWhile(pArray) {
	var accum = 0;
  	var index = pArray.length;
	while(index--) {
		accum += pArray[index];
	}
	return accum;
}
function doForEach(pArray) {
	var accum = 0;
	pArray.forEach(function(item) {
		accum += item;
	});
}

​x
 
// Create an array of 1000 random intergers between 1 and 10000var arrRandom = [];for(var intCtr=0; intCtr<1000; intCtr++) {  arrRandom.push(Math.floor(Math.random() * Math.floor(10000)));}​function reduceCallback(accum, curr) {    return accum+curr;}​function doRedeuce(pArray) {    return pArray.reduce(reduceCallback);}function doLoop(pArray) {    var accum = 0;    for(var intCtr=0; intCtr<pArray.length; intCtr++) {        accum += pArray[intCtr];    }    return accum;}function decrWhile(pArray) {    var accum = 0;    var index = pArray.length;    while(index--) {        accum += pArray[index];    }    return accum;}function doForEach(pArray) {    var accum = 0;    pArray.forEach(function(item) {        accum += item;    });}

Tests:

reduce
var redeuceResult=0; redeuceResult = doRedeuce(arrRandom);
var redeuceResult=0;
redeuceResult = doRedeuce(arrRandom);
for loop
var loopResult=0; loopResult = doLoop(arrRandom);
var loopResult=0;
loopResult = doLoop(arrRandom);
forEach
var forEachResult=0 forEachResult = decrWhile(arrRandom)
var forEachResult=0
forEachResult = decrWhile(arrRandom)
decrement while
var decrWhileResult=0; decrWhileResult = doForEach(arrRandom)
var decrWhileResult=0;
decrWhileResult = doForEach(arrRandom)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
reduce
for loop
forEach
decrement while

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:127.0) Gecko/20100101 Firefox/127.0

Browser/OS: Firefox 127 on Ubuntu

View result in a separate tab

Test name	Executions per second
reduce	664961.1 Ops/sec
for loop	1255454.0 Ops/sec
forEach	755513.2 Ops/sec
decrement while	253727.5 Ops/sec

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

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

Benchmark Overview

The test measures the performance of four different approaches to summing 1000 random numbers:

Array.reduce()
For loop
Array.forEach() (with a custom decrementing index)
Custom "decrement while" loop

Approach 1: Array.reduce()

Array.reduce() is a built-in JavaScript function that reduces an array to a single value by applying a callback function to each element in the array. In this case, the callback function simply adds the current number to the accumulator.

Pros:

Concise and readable code
Built-in functionality makes it easy to understand and implement

Cons:

May have performance overhead due to the need to create an iterator object and iterate over the array
Can be slower than a custom loop for large arrays

Approach 2: For Loop

A traditional for loop iterates over the elements of an array, executing a block of code for each element.

Pros:

Fast execution speed, as it doesn't require creating an iterator object or iterating over the array
Control over iteration order and index access

Cons:

Can be verbose and less readable than other approaches
May not be suitable for large arrays due to stack size limitations

Approach 3: Array.forEach()

Array.forEach() is another built-in JavaScript function that executes a callback function for each element in an array. In this case, the callback function adds the current number to the accumulator.

Pros:

Similar to Array.reduce(), but with a more concise syntax
Can be faster than Array.reduce() due to optimized iterator implementation

Cons:

May have performance overhead due to the need to create an iterator object and iterate over the array
Custom decrementing index is not supported by default

Approach 4: Custom "Decrement While" Loop

This custom loop uses a decrementing index to access elements in the array, similar to a traditional for loop.

Pros:

Fast execution speed, as it doesn't require creating an iterator object or iterating over the array
Control over iteration order and index access

Cons:

May be less readable than other approaches due to the custom logic
Not supported by default in JavaScript, requiring manual implementation

Library Used

None explicitly mentioned, but Math.random() is used to generate random numbers.

Special JS Features/Syntax

None explicitly mentioned.

Alternative Approaches

Other approaches that could be tested include:

Using Array.prototype.map() with a callback function
Using Array.prototype.every() or Array.prototype.some() with a callback function
Using Web Workers for parallel computation

Note that these alternatives may not provide significant performance improvements over the existing approaches and would require additional benchmarking to confirm.

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The test measures the performance of four different approaches to summing 1000 random numbers:

1. `Array.reduce()`
2. For loop
3. `Array.forEach()` (with a custom decrementing index)
4. Custom "decrement while" loop

**Approach 1: `Array.reduce()`**

`Array.reduce()` is a built-in JavaScript function that reduces an array to a single value by applying a callback function to each element in the array. In this case, the callback function simply adds the current number to the accumulator.

Pros:

* Concise and readable code
* Built-in functionality makes it easy to understand and implement

Cons:

* May have performance overhead due to the need to create an iterator object and iterate over the array
* Can be slower than a custom loop for large arrays

**Approach 2: For Loop**

A traditional for loop iterates over the elements of an array, executing a block of code for each element.

Pros:

* Fast execution speed, as it doesn't require creating an iterator object or iterating over the array
* Control over iteration order and index access

Cons:

* Can be verbose and less readable than other approaches
* May not be suitable for large arrays due to stack size limitations

**Approach 3: `Array.forEach()`**

`Array.forEach()` is another built-in JavaScript function that executes a callback function for each element in an array. In this case, the callback function adds the current number to the accumulator.

Pros:

* Similar to `Array.reduce()`, but with a more concise syntax
* Can be faster than `Array.reduce()` due to optimized iterator implementation

Cons:

* May have performance overhead due to the need to create an iterator object and iterate over the array
* Custom decrementing index is not supported by default

**Approach 4: Custom "Decrement While" Loop**

This custom loop uses a decrementing index to access elements in the array, similar to a traditional for loop.

Pros:

* Fast execution speed, as it doesn't require creating an iterator object or iterating over the array
* Control over iteration order and index access

Cons:

* May be less readable than other approaches due to the custom logic
* Not supported by default in JavaScript, requiring manual implementation

**Library Used**

None explicitly mentioned, but `Math.random()` is used to generate random numbers.

**Special JS Features/Syntax**

None explicitly mentioned.

**Alternative Approaches**

Other approaches that could be tested include:

* Using `Array.prototype.map()` with a callback function
* Using `Array.prototype.every()` or `Array.prototype.some()` with a callback function
* Using Web Workers for parallel computation

Note that these alternatives may not provide significant performance improvements over the existing approaches and would require additional benchmarking to confirm.

Related benchmarks:

Array.reduce vs for loop vs Array.forEach vs decrement while (version: 0)

A test summing 1000 random numbers, 1 - 10000

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

Created: 6 years ago by: Guest

Jump to the latest result

reduce

for loop

forEach

decrement while

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):