Benchmark: For vs Foreach vs Map 100.000

Script Preparation code:

var arr = [];
    for (var i = 0; i < 100000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

For
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }
Foreach
arr.forEach(function (item){ someFn(item); })
Map
arr.map(item => someFn(item))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
For
Foreach
Map

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 dive into the world of JavaScript microbenchmarks.

**What is tested?**

The provided JSON represents a benchmark test case that compares three different approaches to iterate over an array in JavaScript:

1. **For loop**: A traditional `for` loop that iterates over the array using an index variable.
2. **Foreach loop**: The `forEach()` method, which executes a callback function for each element in the array without requiring explicit indexing.
3. **Map() method**: The `map()` method, which creates a new array with the results of applying a provided function to each element in the original array.

**Options comparison**

The three approaches have different characteristics that affect their performance:

* **For loop**: This approach has direct access to the array elements through the index variable. However, it requires manual indexing and can be less efficient than other methods.
* **Foreach loop**: The `forEach()` method provides a more elegant way to iterate over arrays, as it eliminates the need for explicit indexing. However, it may incur additional overhead due to function calls.
* **Map() method**: The `map()` method is optimized for performance and can be faster than other approaches because it avoids unnecessary function calls.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **For loop**:
	+ Pros: Direct access to array elements, no additional overhead.
	+ Cons: Manual indexing can lead to errors or slow performance.
* **Foreach loop**:
	+ Pros: Elegant and concise syntax, less prone to errors.
	+ Cons: May incur additional function call overhead.
* **Map() method**:
	+ Pros: Optimized for performance, avoids unnecessary function calls.
	+ Cons: Can be more verbose than other approaches.

**Library usage**

The `someFn` function is a custom function that multiplies its input by 3 and then by 8. It's not a built-in JavaScript library or syntax feature; rather, it's a simple example function used to demonstrate the performance differences between the three iterations methods.

**Special JS features or syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark. The code is written using standard JavaScript syntax and does not utilize any advanced or experimental features.

**Other alternatives**

If you're interested in exploring other iteration methods, here are a few examples:

* **Array.prototype.reduce()**: A method that reduces an array to a single value by applying a function to each element.
* **Set.iterate()**: Not available in standard JavaScript (though some implementations provide similar functionality).
* **Generator functions**: Can be used as iterators for arrays, but may have performance implications due to the overhead of generator execution.

Keep in mind that these alternatives might not be as efficient or straightforward to use as the `for`, `forEach`, and `map()` methods.

Related benchmarks:

For vs Foreach vs Map 100.000 (version: 0)

Comparing performance of: For vs Foreach vs Map

Created: 4 years ago by: Guest

Jump to the latest result

For

Foreach

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):