Benchmark: Arary iteration comparison

Script Preparation code:

   var arr = [];
   for (var i = 0; i < 1000; i++) {
       arr[i] = i;
   }

   function someFn(i) {
       return i * 3 * 8;
   }

Tests:

for-native
var newArr = []; for (var i = 0, len = arr.length; i < len; i++) { newArr.push(someFn(arr[i])); }
for-with-init
var newArr = new Array(arr.length); for (var i = 0, len = arr.length; i < len; i++) { newArr.push(someFn(arr[i])); }
for..of-native
var newArr = []; for (const el of arr) newArr.push(someFn(el));
for..of-with-init
var newArr = new Array(arr.length); for (const el of arr) newArr.push(someFn(el));
map
var newArr = arr.map(someFn)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for-native
for-with-init
for..of-native
for..of-with-init
map

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):

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**Benchmark Overview**

The MeasureThat.net benchmark measures the performance of different JavaScript iteration methods: native for loops, with initialization, and array methods (map). The test compares the execution speed of these methods in creating an array by iterating over a large array.

**Iteration Methods Compared**

1. **Native For Loops**: This involves using traditional `for` loops to iterate over the array.
	* Pros:
		+ Simple and familiar syntax
		+ Works across different browsers and environments
	* Cons:
		+ Can be slower due to overhead of manual indexing
2. **For Loops with Initialization**: This method uses a separate variable to store the length of the array, reducing the need for manual indexing.
	* Pros:
		+ Similar performance to native for loops (less overhead)
		+ Still easy to understand and use
3. **Array Methods** (`map()`):
	* Pros:
		+ Concise syntax and efficient execution
		+ Less prone to errors due to higher-level abstraction
4. **For Loops with Initialization using `const`**: This method uses a `const` variable to store the length of the array, similar to the previous approach.
	* Pros:
		+ Similar performance to native for loops (less overhead)
		+ Still easy to understand and use

**Comparison Summary**

| Method | Performance |
| --- | --- |
| Native For Loops | Slowest |
| For Loops with Initialization | Similar to native for loops |
| Array Methods (`map()`)) | Fastest |
| For Loops with Initialization using `const` | Similar to native for loops |

**Library Used: None**

There is no specific library used in this benchmark. The tests focus on the built-in JavaScript features and methods.

**Special JS Feature or Syntax: `for...of`**

The `for...of` loop is a newer, more modern syntax introduced in ECMAScript 2015 (ES6). It allows iterating over arrays without manual indexing.

**Pros of Using `for...of`**

* Concise and readable syntax
* Less error-prone due to automatic handling of array length

**Cons of Using `for...of`**

* May be slower than traditional for loops or for loops with initialization (due to increased overhead)
* Not supported in older browsers or environments

**Other Alternatives**

* Other iteration methods, such as using `forEach()` or custom loop implementations, could be tested in future benchmarks.
* Comparing the performance of different array constructors (e.g., `Array()`, `new Array()`) might also be interesting.

Keep in mind that the actual performance results may vary depending on specific use cases and environments.

Related benchmarks:

Arary iteration comparison (version: 0)

1. for-native 2. for-with-init 3. for..of-native 4. for..of-with-init 5. map

Comparing performance of: for-native vs for-with-init vs for..of-native vs for..of-with-init vs map

Created: 3 years ago by: Guest

Jump to the latest result

for-native

for-with-init

for..of-native

for..of-with-init

map

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):