Benchmark: Array.reduce vs for loop vs Array.forEach vs for of loop (debugged)

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 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 = doRedeuce(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.

Measuring the performance of different JavaScript looping constructs is crucial for understanding the language's efficiency and optimizing code.

**Benchmark Overview**

The provided benchmark compares four common looping methods in JavaScript:

1. `Array.prototype.reduce()`
2. Traditional `for` loop
3. `Array.prototype.forEach()` with a callback function
4. A newer looping construct called `for...of`

**Options Compared**

Each option is compared based on their execution performance, measured by the number of executions per second (ExecutionsPerSecond).

**Comparison Options and Their Pros/Cons:**

1. **`Array.prototype.reduce()`**:
	* Pros: Can be more efficient for array operations since it avoids the need to manually increment an index.
	* Cons: May have higher overhead due to its functional programming nature.
2. **Traditional `for` loop**:
	* Pros: Highly efficient, easy to read and understand, and can take advantage of compiler optimizations.
	* Cons: Requires manual indexing, which can be error-prone.
3. **`Array.prototype.forEach()` with a callback function**:
	* Pros: Convenient for iterating over arrays, but may have higher overhead due to the use of a callback.
	* Cons: May not be as efficient as traditional loops or `for...of`.
4. **`for...of` looping construct**:
	* Pros: Modern and concise, easy to read, and optimized for performance in modern browsers.
	* Cons: Limited browser support, may require ES6+ syntax.

**Library Used**

In the provided benchmark, no specific libraries are used beyond `Math.random()` for generating random numbers. However, some JavaScript engines (like V8) might have additional optimizations or features not explicitly mentioned here.

**Special JS Features**

The test cases utilize a newer looping construct called `for...of`, which is part of ES6+ syntax and has better performance in modern browsers compared to traditional loops.

**Alternatives**

If you're interested in exploring alternative looping constructs, consider:

* **`Array.prototype.map()`**: Can be used for transforming arrays without re-indexing.
* **`Set` data structures**: Efficient for fast lookups and insertions.
* **`Async/await`**: Suitable for handling asynchronous operations with a more synchronous-like syntax.

**Additional Considerations**

When measuring performance in JavaScript, keep the following in mind:

* **Browser differences**: Results may vary depending on the browser's engine, version, and configuration.
* **Loop optimization techniques**: Use techniques like caching, memoization, or parallel processing to optimize loop performance.
* **Function call overhead**: Excessive function calls can introduce significant overhead; consider using native functions instead of wrapped versions.

The provided benchmark should give you a good starting point for understanding the relative performance of different looping constructs in JavaScript.

Related benchmarks:

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

A test summing 1000 random numbers, 1 - 10000

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

Created: 6 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):