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

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]; });
for..of
for (var i of array) { array[i]; }
reduce
array.reduce(function(i) { array[i]; }, {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
for..of
reduce

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.

**Overview of the Benchmark**

The provided benchmark measures the performance of different loop constructs in JavaScript: `for`, `foreach`, `some`, and `for..of`. It tests how many times each construct can execute within one second.

**Loop Constructs Compared**

1. **`for`**: A traditional loop that uses a variable to iterate over an array.
2. **`foreach`**: An iterative method that executes a callback function for each element in the array.
3. **`some`**: A method that returns `true` as soon as it finds a true value, and then stops iterating.
4. **`for..of`**: A modern loop construct introduced in ECMAScript 2015 (ES6), which uses the `for...of` keyword to iterate over an iterable.

**Pros and Cons of Each Loop Construct**

1. **`for`**:
	* Pros: Simple, well-established, and widely supported.
	* Cons: Can be verbose and error-prone if not used correctly.
2. **`foreach`**:
	* Pros: More concise than `for` loops, with a clear intent for iteration.
	* Cons: May lead to performance issues if the callback function is complex or side-effecting.
3. **`some`**:
	* Pros: Returns early as soon as it finds a true value, which can improve performance.
	* Cons: Can be tricky to use correctly and understand its behavior.
4. **`for..of`**:
	* Pros: Modern, concise, and efficient, with good support in most browsers.
	* Cons: May not be as widely supported by older browsers.

**Library Used**

None of the benchmark test cases explicitly mention using any external libraries beyond what's included in the browser environment (e.g., `Array.prototype.forEach`, `Array.prototype.some`).

**Special JS Features or Syntax**

The benchmark does not include any special JavaScript features or syntax that would affect its behavior. However, it's worth noting that some browsers might have additional performance optimizations for specific loop constructs due to their implementation details.

**Other Alternatives**

1. **`while` loops**: Another traditional looping construct in JavaScript.
2. **`array.prototype.map()`**: A method that creates a new array with the results of applying a provided function to each element in the original array.
3. **`array.prototype.filter()`**: A method that creates a new array with all elements that pass a test implemented by a provided function.

These alternatives could be interesting to add as additional benchmark cases, but they are not included in this specific comparison.

Related benchmarks:

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

Compare loop performance

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

Created: 2 years ago by: Guest

Jump to the latest result

for

foreach

some

for..of

reduce

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):