Benchmark: For loop differences

Script Preparation code:

var noop = (...args) => void args;

var array = Array.from({ length: 10_000 }, (_, idx) => idx);

Tests:

for
for (let idx = 0; idx < array.length; idx++) { noop(array[idx]); }
for..of
for (const item of array) { noop(item); }
Array#forEach
array.forEach((item) => noop(item));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
for..of
Array#forEach

Fastest: N/A

Slowest: N/A

Latest run results:

No previous 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 on MeasureThat.net.

**Benchmark Definition**

The benchmark measures the performance difference between three different approaches to iterate over an array:

1. **For loop**: A traditional, explicit loop using a `for` statement.
2. **For...of loop**: A newer, more concise way to iterate over arrays and other iterables using a `for...of` statement.
3. **Array#forEach**: A built-in method for iterating over an array.

**Options Compared**

The benchmark compares the performance of these three approaches:

* For loop: An explicit loop using a `for` statement, where each iteration is performed explicitly.
* For...of loop: A concise way to iterate over arrays and other iterables using a `for...of` statement.
* Array#forEach: A built-in method for iterating over an array.

**Pros and Cons**

Here are the pros and cons of each approach:

1. **For loop**:
	* Pros: Explicit control, no overhead from built-in methods.
	* Cons: More verbose, slower due to explicit iteration.
2. **For...of loop**:
	* Pros: Concise, easier to read, faster than explicit loops.
	* Cons: Limited control over iteration, may not work with non-array iterables.
3. **Array#forEach**:
	* Pros: Fast, convenient, works with most array-like objects.
	* Cons: May have overhead due to built-in method invocation.

**Library and Purpose**

None of the benchmarks use any external libraries or frameworks. However, `Array` is a built-in JavaScript object that provides methods for working with arrays.

**Special JS Features/Syntax**

The benchmark uses the following special features/syntax:

* **For...of loop**: Introduced in ECMAScript 2015 (ES6), this syntax allows iterating over arrays and other iterables using a concise, for-each-like structure.
* **Array#forEach**: Built-in method introduced in ECMAScript 2009, providing a convenient way to iterate over arrays.

**Other Alternatives**

If you're interested in exploring alternative approaches to iteration, consider the following:

1. **While loop**: An explicit loop using a `while` statement, offering more control than `for` loops but potentially slower.
2. **Closures**: Using functions as iterables or closures to encapsulate state, which can be useful for more complex iterations.
3. **Generators and iterators**: Techniques for creating iterative functions that produce values one at a time, often used in libraries like Lodash.

Keep in mind that the choice of iteration approach depends on your specific use case, performance requirements, and personal preference.

Related benchmarks:

For loop differences (version: 0)

Comparing performance of: for vs for..of vs Array#forEach

Created: 4 years ago by: Guest

Jump to the latest result

for

for..of

Array#forEach

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):