Benchmark: Loop Benchmark. - MeasureThat.net

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

foreach
arr.forEach(function (item){ someFn(item); })
for
for (i = 0; i < arr.length; i++) { someFn(i); }
map
arr.map(item => someFn(item))
for .. of
for (let a of arr) { someFn(a) }
for .. in
for (let a in arr) { someFn(a) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
for .. of
for .. in

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach.

**Benchmark Context**

The benchmark measures the execution performance of four different loop constructs in JavaScript:

1. `forEach`
2. `for` (traditional)
3. `map`
4. `for .. of`

Each test case uses a similar script preparation code that generates an array of 1000 elements and defines a simple function `someFn(i)` that calculates the product of three numbers.

**Library Used: None**

There is no library used in this benchmark.

**JavaScript Features/Syntax**

The benchmark doesn't use any special JavaScript features or syntax. It only uses standard JavaScript constructs.

**Loop Construct Comparison**

Here's an explanation of each loop construct and their pros/cons:

1. **`forEach`**
	* Pros: Easy to read, concise, and expressive. It allows iteration over arrays without explicitly indexing.
	* Cons: May have performance overhead due to the additional function call overhead.
2. **`for` (traditional)**
	* Pros: Performance-oriented, as it avoids the overhead of function calls.
	* Cons: Can be verbose and less readable than `forEach`.
3. **`map`**
	* Pros: Returns a new array with transformed values, making it easy to chain operations.
	* Cons: May require additional memory allocation, and its performance can be slower due to the intermediate array creation.
4. **`for .. of`**
	* Pros: Similar to `forEach`, but provides more flexibility in iteration (e.g., iterating over custom objects).
	* Cons: May have similar performance overhead as `forEach`.

**Benchmark Results**

The latest benchmark results show that:

1. `for .. of` has the highest execution speed.
2. `map` follows closely behind.
3. `for` is slower due to its traditional approach.
4. `forEach` is the slowest, likely due to the additional function call overhead.

**Other Alternatives**

If you're interested in exploring other loop constructs or optimization techniques, consider looking into:

1. **Iteration loops**: Using simple `while` loops for iteration, which can be more performance-oriented than traditional `for` loops.
2. **Generator functions**: Using generator functions to create iterators, which can provide more flexibility and potentially better performance.
3. **Native array methods**: Exploring native array methods like `reduce()`, `filter()`, or `every()` which may offer better performance for specific use cases.

Keep in mind that the best approach depends on your specific use case, performance requirements, and code readability concerns.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36

Browser/OS: Chrome 67 on Mac OS X 10.13.6

View result in a separate tab

Test name	Executions per second
foreach	19835.4 Ops/sec
for	10065.7 Ops/sec
map	18976.0 Ops/sec
for .. of	20564.1 Ops/sec
for .. in	14424.2 Ops/sec

Related benchmarks:

Loop Benchmark. (version: 0)

Comparing performance of: foreach vs for vs map vs for .. of vs for .. in

Created: 6 years ago by: Guest

Jump to the latest result

foreach

for

map

for .. of

for .. in

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):