Benchmark: for vs forEach - MeasureThat.net

Tests:

for loop
var testArray = []; for (var i = 1; i <= 100; i++) { testArray.push(i); } for(var i = 0, length = testArray.length; i < length; i += 1) { console.log(testArray[i]); }
forEach
var testArray = []; for (var i = 1; i <= 100; i++) { testArray.push(i); } 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 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/69.0.3497.81 Chrome/69.0.3497.81 Safari/537.36

Browser/OS: Chromium 69 on Ubuntu

View result in a separate tab

Test name	Executions per second
for loop	1531.0 Ops/sec
forEach	705.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is comparing two approaches: `for` loop and `forEach` method (also known as Array.prototype.forEach() in JavaScript). The test cases create an array of numbers from 1 to 100, perform some operations on it, and then log each element to the console using either a `for` loop or the `forEach` method.

**Options Compared**

Two options are being compared:

1. **`for` Loop**: A traditional loop that uses a counter variable (`i`) to iterate over the array elements.
2. **`forEach` Method**: A built-in method that iterates over an array and executes a callback function for each element.

**Pros and Cons of Each Approach**

### `for` Loop

Pros:

* **Performance**: In general, `for` loops can be faster than `forEach` methods because they avoid the overhead of function calls and don't require creating an iterator object.
* **Control**: With a `for` loop, you have more control over the iteration process, such as incrementing the counter variable.

Cons:

* **Code Complexity**: Writing a `for` loop can be more verbose than using the `forEach` method.
* **Error Handling**: If the array is empty or contains null/undefined values, the `for` loop may throw errors.

### `forEach` Method

Pros:

* **Concise Code**: Using the `forEach` method is a concise way to iterate over an array and perform operations on each element.
* **Easy Error Handling**: The `forEach` method automatically skips null or undefined values in the array.

Cons:

* **Performance Overhead**: Calling the `forEach` method can introduce some performance overhead due to function call overhead.
* **Limited Control**: With the `forEach` method, you have less control over the iteration process than with a `for` loop.

**Library and Special JS Features**

There are no libraries mentioned in this benchmark. However, if we were to use other JavaScript features, we might consider:

* **Async/Await**: If we were using asynchronous code, async/await syntax would be an alternative way to write loops.
* **Generators**: We could also explore using generators as a more efficient way to iterate over large datasets.

**Other Considerations**

When writing benchmarks like this one, it's essential to consider the following factors:

* **Language Features**: Be aware of any language features that might affect performance or code complexity, such as type inference, null safety, or caching.
* **Platform-Specific Optimizations**: Some platforms (e.g., WebAssembly) may provide optimizations for certain loops or data structures.
* **Test Variations**: Consider running multiple test variations to account for different scenarios, such as varying array sizes, data distribution, or concurrency levels.

**Alternatives**

If you're interested in exploring alternative approaches, consider the following options:

* **Closures**: You could use closures (function expressions that capture variables from their scope) to create a custom iterator.
* **Iterator Protocols**: Explore implementing custom iterator protocols for your specific use case.
* **WebAssembly**: Consider optimizing loops or data structures using WebAssembly's low-level abstractions.

Keep in mind that the choice of approach depends on your specific requirements, performance constraints, and personal preferences.

Related benchmarks:

for vs forEach (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 llama3.2:3b, generated 2 months ago):