Benchmark: for vs forEach (working)

Script Preparation code:

var testArray = [];

for (var i = 1; i <= 10000; i++) {
   testArray.push(i);
}

Tests:

for loop
for(var i = 0, length = testArray.length; i < length; i += 1) { console.log(testArray[i]); }
forEach
testArray.forEach((item) => { console.log(item); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop
forEach

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3464.0 Safari/537.36

Browser/OS: Chrome 69 on Windows

View result in a separate tab

Test name	Executions per second
for loop	11.5 Ops/sec
forEach	10.7 Ops/sec

Autogenerated LLM Summary (model gemma2:9b, generated 2 months ago):

LLMs can make mistakes. Check important info.

This benchmark compares the performance of two common ways to iterate over an array in JavaScript: using a traditional `for` loop and using the `forEach` method.

**Here's a breakdown:**

* **Test Cases:**
    *  **`for loop`:** This test case uses a classic `for` loop to iterate through each element of the `testArray`. It's a very common approach, often considered more performant in simple cases.
    * **`forEach`:** This test case utilizes the `forEach` method, which is a built-in JavaScript function designed for iterating over arrays. It offers a cleaner syntax and can be more concise.

* **Options Compared:**
    *  **`for` loop:** Provides fine-grained control over iteration. You can directly access and modify the loop counter (`i`) and adjust the increment step (`+=1`). This can be useful for specific use cases where you need precise control.
    * **`forEach`:** Offers a more streamlined syntax and handles array traversal automatically. It's generally considered easier to read and maintain, especially for simpler tasks.

* **Pros and Cons:**

*  **`for` loop:**
        * **Pro:** Potentially faster in some cases due to direct memory access and control over the iteration process.
        * **Con:** Can be more verbose and complex to write compared to `forEach`.
    * **`forEach`:**
        * **Pro:** Cleaner syntax, easier to read and understand, often considered more idiomatic JavaScript.
        * **Con:**  May have slight performance overhead in some scenarios due to function call overhead.

* **Other Considerations:**
    * **Modern Browsers:**  Performance differences between `for` loops and `forEach` are often negligible in modern browsers, as both approaches are optimized efficiently.
    * **Specific Use Cases:** For highly complex or performance-critical iterations, you might explore specialized libraries like Lodash for more fine-tuned control over array operations.

**Alternatives:**

* **`for...of` loop:** Introduced in ES6, this loop provides a concise and readable way to iterate through iterable objects (including arrays) without needing to manage an index manually.  It's often considered a good alternative to `forEach` for simpler iterations.

Let me know if you have any other questions or want to dive deeper into specific aspects of the benchmark!

Related benchmarks:

for vs forEach (working) (version: 0)

Comparing performance of: for loop vs forEach

Created: 6 years ago by: Guest

Jump to the latest result

for loop

forEach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated 2 months ago):