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

Script Preparation code:

var array = [];
for(let x = 0; x < 1000; x++) {
  array.push(x);
}

Tests:

for
for (var i = 0; i < array.length; i++) { const result = array[i]; }
foreach
array.forEach(function(v) { const result = v; });
some
array.some(function(v) { const result = v; });
for..of
for (var v of array) { const result = v; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
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):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

MeasureThat.net is testing the performance of four different loop constructs:

1. `for` loop
2. `forEach` loop (part of the Array prototype)
3. `some` loop (part of the Array prototype)
4. `for...of` loop (new in ECMAScript 2015)

**Options being compared**

The test is comparing the performance of these four loop constructs on a simple array manipulation task: iterating over an array and performing some operation on each element.

**Pros and Cons of each approach:**

1. **`for` loop**: This is a traditional, iterative loop construct that's easy to understand and use. However, it can lead to variable scope issues if the loop variable is not properly scoped.
2. **`forEach` loop**: This is a more modern, functional loop construct that's part of the Array prototype. It's concise and expressive, but may be slower than traditional `for` loops due to its overhead.
3. **`some` loop**: Similar to `forEach`, this loop is part of the Array prototype and provides a short-circuiting behavior that can lead to performance benefits for large arrays.
4. **`for...of` loop**: This new loop construct in ECMAScript 2015 provides a more modern, concise way of iterating over arrays. It's generally faster than traditional `for` loops and can handle complex iteration scenarios.

**Library usage**

In this benchmark, none of the test cases use any external libraries or frameworks that would introduce additional performance overhead.

**Special JS features/syntax**

The only special feature used in these tests is the `for...of` loop, which was introduced in ECMAScript 2015. The `forEach`, `some`, and traditional `for` loops are all part of the standard JavaScript language.

**Alternatives**

Other alternatives for iterating over arrays include:

* Using `Array.prototype.reduce()` or `Array.prototype.find()`
* Using a callback function with `array.map()`, `array.filter()`, or `array.forEach()`
* Using a third-party library like Lodash

However, these alternatives are not tested in this benchmark.

I hope this explanation helps!

Related benchmarks:

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

Compare loop performance

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

Created: 3 years ago by: Registered User

Jump to the latest result

for

foreach

some

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):