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

Script Preparation code:

var array = new Array(100);

Tests:

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

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):

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Let's break down the provided benchmark and its various components.

**Benchmark Definition JSON**

The benchmark is designed to compare the performance of four different loop constructs in JavaScript: `for`, `forEach`, `some`, and `for..of`. The script preparation code creates an array of 100 elements, which serves as the test data for the loops.

**Loop Constructs Compared**

Here's a brief overview of each loop construct:

1. **`for`**: A traditional `for` loop that uses a counter variable (`i`) to iterate over the array elements.
2. **`forEach`**: The `Array.prototype.forEach()` method, which executes a callback function for each element in the array without incrementing a counter variable.
3. **`some`**: The `Array.prototype.some()` method, which returns `true` if at least one element in the array passes the test implemented by the provided function.
4. **`for..of`**: A newer loop construct introduced in ECMAScript 2015 (ES6), which uses a for-of loop to iterate over iterable arrays.

**Pros and Cons of Each Approach**

1. **`for`**:
	* Pros: Simple, efficient, and widely supported.
	* Cons: Can be verbose, especially when dealing with large arrays or complex logic.
2. **`forEach`**:
	* Pros: Concise, easy to read, and suitable for simple loops.
	* Cons: May not be as efficient as other approaches, especially in performance-critical code.
3. **`some`**:
	* Pros: Convenient for testing a single element without incrementing a counter variable.
	* Cons: Can be slower than traditional `for` or `forEach` loops due to the overhead of function invocation.
4. **`for..of`**:
	* Pros: Modern, concise, and suitable for simple loops with minimal logic.
	* Cons: May not be supported in older browsers or environments.

**Library/Function Used**

None of the provided loop constructs rely on external libraries or functions beyond what's included in the JavaScript standard library.

**Special JS Features/Syntax**

There are no special JS features or syntax used in this benchmark. The loops only utilize basic JavaScript language features.

**Alternative Approaches**

Other alternatives for comparing loop performance could include:

1. **`map()`**: Using `Array.prototype.map()` to perform a transformation on each element, which can be comparable to the other loops.
2. **`reduce()`**: Utilizing `Array.prototype.reduce()` to accumulate values or perform an operation on each element.
3. **Custom implementation using `index` and `length` variables**: Implementing a custom loop using manual indexing and length tracking.

However, these alternative approaches might not be directly comparable to the original four loops ( `for`, `forEach`, `some`, and `for..of` ), as they introduce additional logic or transform the data in distinct ways.

Related benchmarks:

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

Compare loop performance

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

Created: 6 years ago by: Guest

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):