Benchmark: Array loop vs foreach vs map e

Script Preparation code:

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

Tests:

foreach
arr.forEach(someFn)
for
for (var i = 0; i < arr_len; i++) { someFn(arr[i]); }
map
arr.map(someFn)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36

Browser/OS: Chrome 91 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
foreach	79531.6 Ops/sec
for	4257.6 Ops/sec
map	64930.4 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what is tested in each benchmark.

**Benchmark Definition**

The benchmark measures the performance of three different approaches for iterating over an array:

1. `arr.forEach(someFn)`: This approach uses the `forEach` method, which calls a provided function on every element in the array.
2. `for (var i = 0; i < arr_len; i++) { someFn(arr[i]); }`: This approach uses a traditional `for` loop to iterate over the array, calling the `someFn` function for each element.
3. `arr.map(someFn)`: This approach uses the `map` method, which creates a new array by applying the provided function to every element in the original array.

**Options Compared**

The benchmark compares the performance of these three approaches:

* **Pros and Cons:**
	+ `forEach`: This approach is concise and easy to read, but it can be less efficient than traditional loops because it uses a loop under the hood.
	+ Traditional `for` loop: This approach provides fine-grained control over the iteration process, but it requires more code to set up.
	+ `map`: This approach creates a new array, which can lead to increased memory usage. However, it is often faster than traditional loops because it uses optimized C++ implementation under the hood.
* **Other Considerations:**
	+ Performance differences between these approaches are likely due to the way JavaScript engines (in this case, Chrome) implement iteration and function calls.
	+ The `forEach` method may introduce additional overhead due to its loop-like behavior.

**Libraries Used**

None of the provided benchmark definitions use any external libraries.

**Special JS Features or Syntax**

The benchmark does not include any special JavaScript features or syntax. It only uses standard JavaScript constructs, such as loops and functions.

**Other Alternatives**

There are alternative approaches for iterating over arrays in JavaScript, including:

* `for...in` loop: This approach iterates over the properties of an object (including arrays), which can be less efficient than traditional loops.
* `reduce()` method: This approach reduces a sequence of values to a single output value, but it is not typically used for simple array iteration.

It's worth noting that modern JavaScript engines are optimized for performance, and these differences in execution speed may not be significant in most cases. However, the benchmark can still provide insights into the performance characteristics of different iteration approaches.

Related benchmarks:

Array loop vs foreach vs map e (version: 0)

Comparing performance of: foreach vs for vs map

Created: 3 years ago by: Guest

Jump to the latest result

foreach

for

map

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):