Benchmark: Array loop vs foreach vs map vs while vs some vs every vs filter vs find

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

foreach
arr.forEach(function (item){ someFn(item); })
for
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }
map
arr.map(item => someFn(item))
while
let i = 0, len = arr.length; while (i<len) { someFn(arr[i]); i++; }
some
arr.some(item => someFn(item))
every
arr.every(item => someFn(item))
filter
arr.filter(item => someFn(item))
find
arr.find(item => someFn(item))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
while
some
every
filter
find

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Measuring the performance of different JavaScript iteration methods is crucial for understanding the trade-offs between various approaches.

**Benchmark Overview**

The provided benchmark compares the execution speed of eight different iteration methods:

1. `forEach`
2. Traditional `for` loop
3. `map`
4. `while` loop
5. `some`
6. `every`
7. `filter`
8. `find`

Each method is executed in isolation, and the benchmark results are provided.

**Comparison of Iteration Methods**

1. **Traditional `for` loop**: This method uses a fixed index variable (`i`) to iterate over the array. It's a simple and straightforward approach.
	* Pros: Easy to understand, efficient, and widely supported.
	* Cons: Limited flexibility, can lead to off-by-one errors if not used carefully.
2. **`forEach`**: This method is part of the ECMAScript standard and allows for iterating over arrays using a callback function.
	* Pros: Convenient, easy to use, and supports modern browsers.
	* Cons: Can be slower than traditional loops in older browsers or with strict optimization.
3. **`map`**: Similar to `forEach`, but returns a new array with the results of applying a transformation function to each element.
	* Pros: Efficient for creating new arrays, easy to use.
	* Cons: Returns a new array, can be slower than traditional loops if not using lazy evaluation.
4. **`while` loop**: This method uses a conditional statement to control the iteration.
	* Pros: Flexible, allows for more complex logic, and can be faster in some cases.
	* Cons: Can be harder to understand, prone to off-by-one errors, and less widely supported.
5. **`some`** and **`every`**: These methods iterate over arrays using a callback function but return a boolean value indicating whether at least one or all elements pass the test.
	* Pros: Convenient, easy to use, and supports modern browsers.
	* Cons: Can be slower than traditional loops in older browsers or with strict optimization.
6. **`filter`**: Similar to `some`, but returns an array of elements that pass the test.
	* Pros: Efficient for creating arrays with filtered results, easy to use.
	* Cons: Returns a new array, can be slower than traditional loops if not using lazy evaluation.

**Library and Special Features**

The benchmark uses the `someFn` function as a transformation function for all iteration methods. The purpose of `someFn` is unclear without more context, but its name suggests it performs some calculation on each element.

No special features or syntax are mentioned in the provided code snippet.

**Alternative Approaches**

Other alternatives to consider when iterating over arrays include:

* Using `Array.prototype.reduce()` for accumulating values
* Employing lazy evaluation using `Array.prototype.forEach()`
* Utilizing WebAssembly (WASM) or other just-in-time (JIT) compilers for optimized performance

Keep in mind that the choice of iteration method depends on specific requirements, such as performance, readability, and compatibility with older browsers.

In conclusion, this benchmark provides a comprehensive overview of different JavaScript iteration methods. Understanding their strengths and weaknesses is crucial for optimizing code performance and making informed decisions when choosing an iteration approach.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Browser/OS: Chrome 105 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
foreach	23.8 Ops/sec
for	13.7 Ops/sec
map	22.9 Ops/sec
while	13.5 Ops/sec
some	8958735.0 Ops/sec
every	13292647.0 Ops/sec
filter	21.2 Ops/sec
find	8920476.0 Ops/sec

Related benchmarks:

Array loop vs foreach vs map vs while vs some vs every vs filter vs find (version: 0)

Comparing performance of: foreach vs for vs map vs while vs some vs every vs filter vs find

Created: 2 years ago by: Guest

Jump to the latest result

foreach

for

map

while

some

every

filter

find

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):