Benchmark: Array loop vs foreach vs map vs every

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))
every
arr.every((item) => { return someFn(item)} )

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
every

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser/OS: Chrome 87 on Linux

View result in a separate tab

Test name	Executions per second
foreach	13.7 Ops/sec
for	7.9 Ops/sec
map	12.8 Ops/sec
every	7559297.5 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The provided benchmark compares four different approaches to iterate over an array in JavaScript: `forEach`, `for` loop, `map`, and `every`. The test case uses a simple function `someFn(i)` that calculates `i * 3 * 8`.

**Comparison Options**

1. **foreach**: Iterates over the array using the `forEach` method, which calls the provided callback function for each element in the array.
	* Pros: Easy to use and readable code; doesn't require manual index management.
	* Cons: Can be slower than other approaches due to the overhead of calling a separate function on each iteration.
2. **for**: Iterates over the array using a traditional `for` loop, which requires manual index management.
	* Pros: Fast and efficient, especially for large arrays; allows for fine-grained control over indexing and iteration.
	* Cons: Can be verbose and harder to read than other approaches; requires manual index management.
3. **map**: Iterates over the array using the `map` method, which applies a transformation function to each element in the array.
	* Pros: Elegant and concise syntax; transforms the array in place.
	* Cons: May incur additional overhead due to the creation of new arrays or intermediate results.
4. **every**: Iterates over the array using the `every` method, which returns `true` if all elements in the array pass a provided test function.
	* Pros: Concise syntax; easy to use when only one condition needs to be checked per element.
	* Cons: Can be slower than other approaches due to the overhead of calling a separate function on each iteration.

**Library Usage**

The benchmark uses the `someFn` function, which is not a built-in JavaScript library. However, it appears to be a custom function designed for testing and demonstration purposes. There is no additional library usage beyond this simple function.

**Special JS Features or Syntax**

There are no special JS features or syntax used in this benchmark beyond what is standard for modern JavaScript. The `forEach`, `for`, `map`, and `every` methods are all supported by most modern browsers and JavaScript engines, including Chrome 87.

**Alternative Approaches**

Other approaches to iterate over an array could include:

* Using a `while` loop with manual index management
* Using the `reduce()` method or other aggregation functions
* Using a library like Lodash or Ramda for functional programming utilities

These alternative approaches might offer benefits in terms of performance, readability, or conciseness, but may not be as widely supported by browsers and JavaScript engines.

Keep in mind that microbenchmarks can be sensitive to various factors, such as array size, device hardware, and browser version. The results presented on MeasureThat.net are specific to the provided test case and might not generalize to all scenarios.

Related benchmarks:

Array loop vs foreach vs map vs every (version: 1)

Comparing performance of: foreach vs for vs map vs every

Created: 5 years ago by: Registered User

Jump to the latest result

foreach

for

map

every

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):