Benchmark: for vs foreach vs some vs for..of Kyran

Script Preparation code:

var array = new Array(100);

Tests:

for
for (var index = 0; index < array.length; index++) { console.log(array[index]) }
foreach
array.forEach((value) => { console.log(value); });
for..of
for (const value of array) { console.log(value); }
for..in
for (const index in array) { console.log(array[index]); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into explaining the benchmark.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking test case on MeasureThat.net, which compares the performance of different loop iteration methods: `for`, `forEach`, `for..of`, and `for..in`.

**Loop Iteration Methods Compared**

1. **`for`**: A traditional loop using a variable (`index`) to iterate through an array.
2. **`forEach`**: A modern method for iterating over arrays, which executes a callback function once for each element in the array.
3. **`for..of`**: Another modern method for iterating over arrays, which uses a `for...of` loop to iterate over the elements of the array.
4. **`for..in`**: A loop that iterates over the indices of an object (not directly applicable to arrays, but used as a control in this benchmark).

**Options Compared**

The options compared are:

* **Number of iterations**: The number of times each loop iteration method is executed.
* **Array size**: The size of the array being iterated over.

**Pros and Cons of Each Approach**

1. **`for`**:
	* Pros: Simple, widely supported, and easy to understand.
	* Cons: Can be slower than modern methods due to the overhead of incrementing a variable.
2. **`forEach`**:
	* Pros: Modern, concise, and well-supported by most JavaScript engines.
	* Cons: May incur additional overhead due to callback function execution.
3. **`for..of`**:
	* Pros: Modern, concise, and optimized for array iteration.
	* Cons: Less widely supported than `forEach`, but gaining popularity.

**Library Used**

None explicitly mentioned in the provided code snippets.

**Special JS Features or Syntax**

None mentioned in this explanation, as it's focused on explaining the loop iteration methods.

**Other Considerations**

When benchmarking JavaScript performance, consider factors such as:

* Cache locality: The proximity of data to each other in memory.
* Branch prediction: The ability of the CPU to predict the branch (conditional jump) outcome.
* Loop overhead: The time spent on loop iterations themselves, not just the execution.

**Alternative Benchmarks**

If you're interested in exploring alternative JavaScript benchmarking tools or test cases, consider:

1. **Google's JSPerf**: A popular online JavaScript performance benchmarking tool.
2. **Benchmark.js**: A lightweight JavaScript benchmarking library.
3. **Benchmarcking libraries like js-benchmark**

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36

Browser/OS: Chrome 88 on Linux

View result in a separate tab

Test name	Executions per second
for	359.2 Ops/sec
foreach	3225875.5 Ops/sec
for..of	371.2 Ops/sec
for..in	3190909.8 Ops/sec

Related benchmarks:

for vs foreach vs some vs for..of Kyran (version: 0)

Compare loop performance

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

Created: 4 years ago by: Guest

Jump to the latest result

for

foreach

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 26 days ago):