Benchmark: Array.reduce vs for loop vs Array.forEach -123

Script Preparation code:

// Create an array of 1000 random intergers between 1 and 10000
var arrRandom = [];
for(var intCtr=0; intCtr<100; 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 doForEach(pArray) {
	var accum = 0;
	pArray.forEach(function(item) {
		accum += item;
	});
}

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce
for loop
forEach

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36

Browser/OS: Chrome 71 on Windows

View result in a separate tab

Test name	Executions per second
reduce	315449.6 Ops/sec
for loop	2245503.5 Ops/sec
forEach	1913004.8 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the benchmark and its various components.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmark that tests three different approaches for summing up an array of numbers: `Array.reduce()`, `for` loop, and `Array.forEach()`.

**Options Compared**

Here's a breakdown of each option:

1. **`Array.reduce()`**: This method uses the `reduce()` function to apply a callback function to each element in the array, accumulating a result.
2. **`For Loop`**: This approach uses a traditional `for` loop to iterate over the array elements and accumulate the sum.
3. **`Array.forEach()`**: This method uses the `forEach()` function to iterate over the array elements and apply a callback function to each one.

**Pros and Cons**

Here's a brief overview of the pros and cons of each approach:

1. **`Array.reduce()`**:
	* Pros: Efficient, concise, and easy to read.
	* Cons: May be slower for large arrays due to overhead from creating an accumulator.
2. **`For Loop`**:
	* Pros: Control over indexing and variable scope.
	* Cons: Can be verbose and harder to read for complex logic.
3. **`Array.forEach()`**:
	* Pros: Simple, readable, and easy to use.
	* Cons: May have performance overhead due to the callback function.

**Library and Purpose**

In this benchmark, two libraries are used:

1. **`Math.random()`**: This is a built-in JavaScript library that generates random numbers.
2. No specific library is used for `Array.reduce`, `for loop`, or `Array.forEach`. However, these methods are part of the native JavaScript API.

**Special JS Features and Syntax**

The benchmark uses the following special JavaScript features:

1. **`let` and `const`**: These keywords are used to declare variables that are not hoisted.
2. **Template literals`: The `template literal` syntax is used to create a string with embedded expressions.
3. **Arrow functions**: The `=>` syntax is used to define small, single-expression functions.

**Other Alternatives**

For summing up an array of numbers, other alternatives might include:

1. **Using `Array.prototype.reduce()` and defining a custom callback function**.
2. **Using a library like Lodash**, which provides a `sum` function for working with arrays.
3. **Using a more functional programming approach**, such as using the `reduceRight()` method.

Keep in mind that these alternatives might have different performance characteristics or trade-offs, and may not be suitable for all use cases.

Related benchmarks:

Array.reduce vs for loop vs Array.forEach -123 (version: 0)

A test summing 1000 random numbers, 1 - 10000

Comparing performance of: reduce vs for loop vs forEach

Created: 6 years ago by: Guest

Jump to the latest result

reduce

for loop

forEach

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):