Benchmark: for vs foreach vs some vs for..of vs while

Script Preparation code:

var array = new Array(100);

Tests:

for
for (var i = 0; i < array.length; i++) { array[i]; }
foreach
array.forEach(function(i) { array[i]; });
some
array.some(function(i) { array[i]; });
for..of
for (var i of array) { array[i]; }
while
var i = 0; var len = array.length; while(i<len) { array[i]; i++ }
for..of with array.entries
for (const [index, element] of array.entries()){ array[index] }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
for..of
while
for..of with array.entries

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1 Safari/605.1.15

Browser/OS: Safari 13 on Mac OS X 10.15.4

View result in a separate tab

Test name	Executions per second
for	64277.9 Ops/sec
foreach	330851.8 Ops/sec
some	331039.4 Ops/sec
for..of	85139.4 Ops/sec
while	126759.0 Ops/sec
for..of with array.entries	84609.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The benchmark definition is a JSON object that outlines the scope and purpose of the benchmark. In this case, it tests the performance of four different loop constructs:

1. `for` loops
2. `forEach` loops
3. `some` loops
4. `for..of` loops

The benchmark also includes a script preparation code (`var array = new Array(100);`) and no HTML preparation code.

**Options Compared**

The benchmark compares the performance of four different loop constructs:

1. **Traditional `for` loop**: uses an explicit counter variable (`i`) to iterate over the array.
2. **`forEach` loop**: uses the `Array.prototype.forEach()` method, which is a built-in array method that executes a callback function for each element in the array.
3. **`some` loop**: uses the `Array.prototype.some()` method, which returns `true` if at least one element in the array passes the test implemented by the provided function.
4. **`for..of` loop**: uses the new `for...of` syntax, which is a more concise and expressive way to iterate over arrays.

**Pros and Cons of Each Approach**

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

1. **Traditional `for` loop**:
	* Pros: easy to understand and implement, works well with small arrays.
	* Cons: can be slow for large arrays due to the overhead of explicit counter management.
2. **`forEach` loop**:
	* Pros: concise and expressive, optimized for performance by browsers.
	* Cons: can be slower than traditional `for` loops due to method call overhead.
3. **`some` loop**:
	* Pros: concise and expressive, can be faster than traditional `for` loops for certain use cases.
	* Cons: may not be as well-supported by older browsers or environments.
4. **`for..of` loop**:
	* Pros: concise and expressive, optimized for performance by modern browsers.
	* Cons: requires support for the new `for...of` syntax, which may not be widely supported.

**Library and Purpose**

The benchmark uses the built-in JavaScript array methods (`forEach`, `some`) to implement the loops. These methods are designed to optimize performance and provide a concise way to iterate over arrays.

**Special JS Features or Syntax**

None of the individual test cases rely on any special JavaScript features or syntax beyond what's necessary for the loops themselves (e.g., using `const` for variable declarations). However, some test cases do use the new `for...of` syntax (`for..of` and `for..of with array.entries`), which is a relatively recent addition to the language.

**Alternatives**

If you're interested in alternative loop constructs or optimizations, you may want to explore other benchmarking frameworks or libraries. Some examples include:

* V8 Micro-Benchmark: a popular benchmarking framework developed by Google's V8 JavaScript engine.
* JSPerf: a web-based benchmarking platform that allows you to compare the performance of different JavaScript code snippets.
* Benchmark.js: a lightweight, modular benchmarking library for Node.js and browser environments.

Keep in mind that each of these alternatives has its own strengths and weaknesses, and may not offer identical features or support to MeasureThat.net.

Related benchmarks:

for vs foreach vs some vs for..of vs while (version: 0)

Compare loop performance for all 4 loops

Comparing performance of: for vs foreach vs some vs for..of vs while vs for..of with array.entries

Created: 4 years ago by: Guest

Jump to the latest result

for

foreach

some

for..of

while

for..of with array.entries

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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