Benchmark: for (i < n) vs Array(n).forEach

Tests:

forloop
let arr = Array(1000); for (let i = 0; i < 1000; i++) { arr[i]; }
forEach
let arr = Array(1000); arr.forEach(it => { it; });
for...of
let arr = Array(1000); for (let it of arr) { it; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forloop
forEach
for...of

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Measuring the performance of JavaScript loops is an important task, and MeasureThat.net provides a useful platform for benchmarking different approaches.

The provided JSON represents three individual test cases: `forloop`, `forEach`, and `for...of`. These tests aim to measure the performance of creating an array and then iterating over it using three different methods: traditional `for` loop, `Array.forEach()` method, and `for...of` loop.

Let's break down each option:

1. **Traditional `for` Loop (`forloop`)**:
This approach involves creating a new array with the desired length (1000 in this case) and then using a traditional `for` loop to iterate over its elements.
Pros:
* Easy to understand and implement for most developers
* Allows for manual control over iteration variables and indexing

Cons:
* Can be slower compared to other approaches due to the overhead of creating an array and managing indices manually

2. **Array.forEach() Method (`forEach`)**:
This approach uses the `Array.prototype.forEach()` method, which iterates over an array using a callback function.
Pros:
* Often faster than traditional `for` loops, as it leverages optimized JavaScript engine implementations
* Reduces the need for manual loop management and indexing

Cons:
* Can be less intuitive for developers unfamiliar with this syntax
* May not perform well on older browsers or environments that don't support modern JavaScript features

3. **For...of Loop (`for...of`)**:
This approach uses a `for...of` loop, which iterates over an array using the `values()` method.
Pros:
* Similar to traditional `for` loops but with improved syntax and readability
* Often faster than `Array.forEach()`, as it's also optimized by modern JavaScript engines

Cons:
* May not be supported in older browsers or environments that don't support this feature
* Can be less intuitive for developers familiar only with traditional `for` loops

In the provided benchmark results, we can see that:

* The `forloop` test performed the best, with an average of 236,632 executions per second.
* The `forEach` test was slightly slower than the `forloop`, but still relatively fast at 228,654 executions per second.
* The `for...of` loop performed similarly to the traditional `for` loop in terms of speed, around 125,339 executions per second.

In summary, the choice between these approaches depends on your specific use case and performance requirements. If you need to iterate over arrays frequently, one of these methods should be suitable for most modern JavaScript environments. However, if you're targeting older browsers or require fine-grained control over iteration variables, traditional `for` loops might still be a better choice.

Other alternatives worth mentioning include:

* Using `Array.prototype.map()` and then iterating over the resulting array (not used in this benchmark)
* Utilizing Web Workers for parallel processing (not used in this benchmark)
* Leveraging native JavaScript methods like `TypedArray` or `Int8Array` for optimized iteration (not used in this benchmark)

Keep in mind that performance differences between these approaches can be relatively small, and other factors like memory allocation, garbage collection, and caching might have a more significant impact on overall application performance.

Related benchmarks:

for (i < n) vs Array(n).forEach (version: 0)

Comparing performance of: forloop vs forEach vs for...of

Created: 4 years ago by: Guest

Jump to the latest result

forloop

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):