Benchmark: for vs foreach vs some

Script Preparation code:

var array = new Array(100);

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/69.0.3497.81 Chrome/69.0.3497.81 Safari/537.36

Browser/OS: Chromium 69 on Ubuntu

View result in a separate tab

Test name	Executions per second
for	43817.8 Ops/sec
foreach	2442198.0 Ops/sec
some	2502363.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring loop performance is crucial in JavaScript development, and the provided benchmark test cases are designed to compare the performance of three popular looping constructs: `for`, `forEach`, and `some`.

**Looping Constructs Comparison**

1. **For Loop**
The `for` loop uses a traditional approach with an explicit counter variable (`i`) that iterates over the array index. This loop is often considered the most efficient among the three options.

Pros:

* Easy to understand and implement
* Provides direct access to the index value
* Can be optimized for performance by using techniques like caching or incrementing the counter only when necessary

Cons:

* May require more manual memory management, as the array length needs to be stored in a variable.
* Can lead to slower execution if not implemented correctly.

2. **ForEach Loop**
The `forEach` loop uses an iterator function that is called for each element in the array. This approach allows for more flexibility and can eliminate the need for explicit indexing.

Pros:

* More concise and easier to read
* Eliminates the need for manual indexing
* Can be used with arrow functions or other types of iterators

Cons:

* May be slower than `for` loops due to additional overhead from the iterator function.
* Can lead to unexpected behavior if not implemented correctly, especially when dealing with side effects.

3. **Some Loop**
The `some` loop uses a predicate function that returns `true` as soon as it finds an element in the array that satisfies the condition. This approach can be useful for early termination and reducing unnecessary iterations.

Pros:

* Can reduce the number of iterations, making it suitable for large datasets
* Provides concise code

Cons:

* May lead to slower execution if not implemented correctly, as the predicate function needs to iterate over the entire array.
* Requires careful consideration of edge cases, such as empty arrays or arrays with only one element.

**Library and Purpose**

In this benchmark, no libraries are explicitly mentioned. However, some libraries might be used indirectly through browser-specific features or extensions.

**JavaScript Feature/Syntax**

The `forEach` loop utilizes a JavaScript feature called "closures" by passing an iterator function as an argument to the `forEach` method. Additionally, some browsers may provide features like WebAssembly support or experimental APIs that might be utilized in the benchmark (e.g., Chromium 69's JavaScript engine has experimental WebAssembly support).

**Other Alternatives**

For comparing loop performance, you can consider using other alternatives:

* **Loops with conditional statements**: Using `if` statements to check for array indices before accessing elements.
* **While loops**: Implementing a while loop that increments the counter until it reaches the desired iteration number.
* **Using built-in methods like `map()` or `filter()`**: These methods can be used to transform arrays, but they might incur additional overhead and may not provide direct access to individual elements.

Keep in mind that the choice of alternative looping constructs will depend on your specific use case and performance requirements.

Related benchmarks:

for vs foreach vs some (version: 0)

Compare loop performance

Comparing performance of: for vs foreach vs some

Created: 8 years ago by: Guest

Jump to the latest result

for

foreach

some

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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