Benchmark: for w/length constant vs foreach vs some vs for..of (3)

Script Preparation code:

var array = new Array(10000);

Tests:

for (lenght 另外儲存)
const length = array.length for (var i = 0; i < length; i++) { }
foreach with operation
array.forEach(function(i) { });
some
array.some(function(i) { });
for..of
for (var i of array) { }
for (lenght 不另外儲存)
for (var i = 0; i < array.length; i++) { }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for (lenght 另外儲存)
foreach with operation
some
for..of
for (lenght 不另外儲存)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36

Browser/OS: Chrome 118 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
for (lenght 另外儲存)	319884.4 Ops/sec
foreach with operation	108578.1 Ops/sec
some	101570.2 Ops/sec
for..of	332441.1 Ops/sec
for (lenght 不另外儲存)	3663.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared options, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The benchmark measures the performance of four different loop approaches:

1. `for` with a length constant (stored in a variable)
2. `foreach` with an operation
3. `some`
4. `for...of`

These loops are used to iterate over a large array of 10,000 elements.

**Options Comparison**

Here's a comparison of the four loop approaches:

1. **For with length constant (stored in a variable)**:
	* Pros: This approach is commonly used and understood by most developers. It avoids creating an unnecessary temporary object.
	* Cons: The length of the array must be stored in a variable, which can lead to additional memory usage. Additionally, this approach can lead to performance issues if the loop counter is not optimized correctly.
2. **Foreach with operation**:
	* Pros: This approach allows for concise code and is easy to read. It also avoids creating an unnecessary temporary object.
	* Cons: The `foreach` loop in JavaScript does not provide direct access to the array's elements, which can lead to performance issues if the loop needs to perform additional operations on each element.
3. **Some**:
	* Pros: This approach is concise and easy to read. It also allows for early termination of the loop when a condition is met.
	* Cons: The `some` loop in JavaScript does not provide direct access to the array's elements, which can lead to performance issues if the loop needs to perform additional operations on each element.
4. **For...of**:
	* Pros: This approach provides direct access to the array's elements and is concise.
	* Cons: The `for...of` loop in JavaScript was introduced later than other loops and may not be as widely supported or understood by older browsers.

**Library Considerations**

In the benchmark, it appears that no external libraries are being used. However, if a library were to be used, some examples of popular libraries for iterating over arrays include:

* Lodash (with its `forEach` function)
* Underscore.js (with its `forEach` function)

These libraries provide additional functionality and optimizations for array iteration.

**Special JS Features/Syntax**

The benchmark uses the following special JavaScript features/syntax:

* The `for...of` loop, which was introduced in ECMAScript 2015.
* The `some` loop, which was introduced in ECMAScript 2009.

These features provide concise and readable ways to iterate over arrays, but may not be supported by older browsers or environments.

**Other Alternatives**

Alternative approaches for iterating over arrays include:

* Using a traditional `for` loop with an index variable
* Using a recursive function to iterate over the array
* Using a library like Lodash or Underscore.js to provide additional functionality and optimizations

Overall, the benchmark provides a good comparison of four common loop approaches in JavaScript, allowing users to choose the most suitable approach for their specific use case.

Related benchmarks:

for w/length constant vs foreach vs some vs for..of (3) (version: 0)

Compare loop performance

Comparing performance of: for (lenght 另外儲存) vs foreach with operation vs some vs for..of vs for (lenght 不另外儲存)

Created: 2 years ago by: Guest

Jump to the latest result

for (lenght 另外儲存)

foreach with operation

some

for..of

for (lenght 不另外儲存)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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