Benchmark: for vs foreach vs for..of (fixed)

Script Preparation code:

var array = new Array(100);

Tests:

for
for (var i = 0, len = array.length; i < len; i++) { array[i]; }
foreach
array.forEach(function(item) { item; });
for..of
for (var item of array) { item; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
for..of

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

The provided benchmark definition and test cases compare the performance of three different loop constructs: `for`, `foreach`, and `for..of`. We'll break down each option, their pros and cons, and other considerations.

**Loop Constructs**

1. **For Loop**
```javascript
for (var i = 0, len = array.length; i < len; i++) {
  array[i];
}
```
Pros:

* Wide support across browsers and environments.
* Easy to understand and implement.

Cons:

* Can be slower due to the extra iterations required for variable initialization and loop termination checks.

2. **Foreach Loop**
```javascript
array.forEach(function(item) {
  item;
});
```
Pros:

* Faster execution compared to traditional `for` loops, as it leverages the engine's optimized array iteration logic.
* Reduced boilerplate code.

Cons:

* May not be supported in older browsers or environments.
* Less control over loop iterations and termination conditions.

3. **For..of Loop**
```javascript
for (var item of array) {
  item;
}
```
Pros:

* Similar to `foreach` but with improved readability and maintainability, thanks to the explicit iteration variable declaration (`var item`).
* Wide support across modern browsers and environments.

Cons:

* May require a minimum JavaScript engine version or feature support.
* Less optimal performance compared to traditional `for` loops or `foreach` loops in some cases.

Now, let's discuss special considerations for the provided test cases:

**Library:**
None of the test cases use any external libraries. They only utilize built-in JavaScript features and arrays.

**Special JS Features/Syntax:**

The test cases do not use any special JavaScript features or syntax that would require additional explanation. However, it's worth noting that the `for..of` loop requires a minimum JavaScript engine version or feature support (ECMAScript 2015+).

**Benchmark Results:**
The latest benchmark results show that:

* The `for..of` loop has the highest execution rate (`ExecutionsPerSecond`) at 5555831.0, followed by the traditional `for` loop at 3435480.75, and finally the `foreach` loop at 117324.4296875.

Keep in mind that these results may vary depending on the specific browser, device platform, operating system, and JavaScript engine version used.

**Alternatives:**

If you're interested in exploring other loop constructs or benchmarking different JavaScript features, MeasureThat.net offers a wide range of benchmarks and test cases. Some examples include:

* Iterating over objects with `for...in` or `for...of`
* Using regular expressions for string matching
* Implementing a simple sorting algorithm (e.g., bubble sort or quicksort)
* Comparing the performance of different array methods (e.g., `map`, `filter`, or `reduce`)

Feel free to explore these and other benchmarks on MeasureThat.net to gain insights into various JavaScript topics and optimize your code for better performance.

Related benchmarks:

for vs foreach vs for..of (fixed) (version: 0)

Compare loop performance

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

Created: 5 years ago by: Guest

Jump to the latest result

for

foreach

for..of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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