Benchmark: for..of VS forEach

Script Preparation code:

var values = new Array(10000);
for (var i = 0; i < values.length; i++) values[i]=i;

Tests:

forEach
var sum = 0; values.forEach(v => sum += v );
for..of
var sum = 0; for (var v of values) sum += v;
forEach func
var sum = 0; values.forEach(function(v) { sum += v } );
for of transpiled
var sum = 0; for (var _i = 0, values_1 = values; _i < values_1.length; _i++) { var v = values_1[_i]; sum += v; }
for of transpiled simple
var sum = 0; for (var i = 0; i < values.length; i++) sum += values[i];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
for..of
forEach func
for of transpiled
for of transpiled simple

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 break down the provided JSON and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark definition is testing the performance difference between two approaches: `for..of` and `forEach`. The script preparation code creates an array of 10,000 values and initializes a variable `sum` to zero. The `for..of` loop iterates over the array using the `values` array as the iterable, while the `forEach` function applies a callback function to each element in the array.

**Options Compared**

The benchmark is comparing four options:

1. **`for..of`**: This syntax uses a new way of iterating over arrays and other iterables. It's more concise than traditional for loops.
2. **`forEach`**: This is a standard method on arrays that applies a callback function to each element.
3. **`forEach func`**: This is an alternative implementation using the `forEach` method with a named function as the callback.
4. **`for of transpiled simple`**: This option uses a traditional for loop with the `values` array as the iterable.

**Pros and Cons**

Here's a brief summary of each option:

* **`for..of`**:
	+ Pros: More concise, easier to read, and often faster than traditional for loops.
	+ Cons: May not be compatible with older browsers or environments that don't support this syntax.
* **`forEach`**:
	+ Pros: Widely supported across modern browsers and engines, easy to understand.
	+ Cons: Can be slower than `for..of` due to the overhead of function calls.
* **`forEach func`**:
	+ Pros: Similar performance characteristics to `forEach`, but with a named function as the callback.
	+ Cons: May add unnecessary complexity for some use cases.
* **`for of transpiled simple`**:
	+ Pros: Most compatible with older browsers and environments, easy to understand.
	+ Cons: Often slower than the other options due to the overhead of traditional for loops.

**Library Usage**

None of these options rely on external libraries. The `forEach` method is a built-in method on arrays in JavaScript.

**Special JS Features or Syntax**

The benchmark uses the following features:

* **`for..of`**: This syntax was introduced in ECMAScript 2015 (ES6) as a new way of iterating over arrays and other iterables.
* **`forEach`**: This is a standard method on arrays that has been part of the JavaScript language since its early days.

**Other Alternatives**

If you're looking for alternative approaches, consider:

* **Loops with traditional indexing**: Using `values[i]` to access each element in an array can be faster than using `forEach`.
* **Map/reduce methods**: These methods are often used for parallel processing and can be more efficient than loops.
* **Async/await or Promises**: If you're dealing with asynchronous code, consider using these constructs instead of traditional for loops.

Keep in mind that the performance differences between these options may vary depending on your specific use case, hardware, and JavaScript engine.

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/93.0.4571.0 Safari/537.36 Edg/93.0.957.0

Browser/OS: Chrome 93 on Linux

View result in a separate tab

Test name	Executions per second
forEach	26755.5 Ops/sec
for..of	55308.8 Ops/sec
forEach func	27798.8 Ops/sec
for of transpiled	154652.5 Ops/sec
for of transpiled simple	720.6 Ops/sec

Related benchmarks:

for..of VS forEach (version: 0)

Comparing performance of: forEach vs for..of vs forEach func vs for of transpiled vs for of transpiled simple

Created: 7 years ago by: Guest

Jump to the latest result

forEach

for..of

forEach func

for of transpiled

for of transpiled simple

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):