Benchmark: Array loop vs foreach vs map 36000

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 36000; 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))

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:

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Autogenerated LLM Summary (model gemma2:9b, generated one year ago):

LLMs can make mistakes. Check important info.

This benchmark compares three different ways to process an array in JavaScript:

**Options Compared:**

* **`forEach`:** This method iterates over each element in the array and executes a provided function for each element. It doesn't return a new array. 
* **`for` loop:**  A classic iterative approach that manually manages the index and steps through each element of the array.
* **`map`:**  This method iterates over each element in the array, applies a provided function to each element, and returns a new array with the results.

**Pros and Cons:**

* **`forEach`:** 
    * **Pros:** Concise syntax, readable for beginners. Good when you primarily need to perform an action on each element without needing a new array.
    * **Cons:** Doesn't return a modified array, can be less efficient than `map` if you need the transformed values.
* **`for` loop:** 
    * **Pros:**  Fine-grained control over the iteration process. Can potentially be the most performant in certain scenarios.
    * **Cons:** More verbose syntax, prone to errors if not carefully managed (e.g., off-by-one errors).

* **`map`:**
    * **Pros:** Returns a new array with transformed values, efficient and readable when creating a new array based on the input array. 
    * **Cons:** Slightly more verbose than `forEach`.

**Other Considerations:**

* **Array Size:** The size of the array has a significant impact on performance. For very large arrays, the differences between these methods might become more pronounced.
* **Function Complexity:** The complexity of the function executed within each method also affects performance. More complex functions will take longer to execute.

**Alternatives:**

While this benchmark focuses on the three main methods, other options exist for array processing in JavaScript:

* **`filter`:** Creates a new array containing elements that pass a test implemented by a provided function.
* **`reduce`:**  Applies a function to each element of an array, accumulating a single value (often used to calculate sums or averages).
* **Libraries:** Libraries like Lodash offer optimized implementations of common array operations, potentially providing performance benefits over built-in methods.

Let me know if you have any more questions about this benchmark or other JavaScript concepts!

Related benchmarks:

Array loop vs foreach vs map 36000 (version: 0)

36000

Comparing performance of: foreach vs for vs map

Created: 4 years ago by: Guest

Jump to the latest result

foreach

for

map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):