Benchmark: Array loop vs Array loop of vs foreach vs map

Script Preparation code:

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

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
for of

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model gemma2:9b, generated one year ago):

LLMs can make mistakes. Check important info.

This benchmark on MeasureThat.net compares the performance of four different approaches to iterating over an array and applying a function to each element:

* **`forEach`:** This method iterates through each element in the array and executes a provided callback function for each element. 
* **`for` loop:** This is a traditional loop that iterates from the first to the last element of the array, accessing each element by its index.
* **`map`:**  This method iterates over each element in the array, applies a provided function to each element, and returns a new array with the results. 
* **`for...of` loop:** This is a modern loop that iterates directly over iterable objects (like arrays) without needing an explicit index.

**Pros and Cons:**

* **`forEach`:**  Simple and readable for basic iterations where you don't need to return a new array. 
    * Con: Can be less efficient than other methods if you need to create a new array based on the results.
* **`for` loop:** Most control over iteration, allows direct access to element indices.
    * Con: More verbose and can be harder to read than newer approaches.
* **`map`:** Efficient for creating new arrays based on existing data.  
    * Con: Can be less readable if you're not familiar with functional programming concepts.
* **`for...of` loop:** Concise and easy to read, especially for simple iterations. 
    * Con: Not as widely supported in older JavaScript versions.

**Other Considerations:**

The `someFn` function is a simple multiplier that doesn't significantly impact performance. The benchmark measures the time it takes to iterate over the array and apply the function.

**Alternatives:**

While these are common methods for iterating over arrays, there are other options:

* **Libraries:** Libraries like Lodash or Ramda provide optimized iteration functions with more features (e.g., filtering, transforming data).
* **Async Iteration:** If your array is large or contains asynchronous operations, you can use async/await or promises to iterate efficiently.

Let me know if you have any other questions!

Related benchmarks:

Array loop vs Array loop of vs foreach vs map (version: 0)

Comparing performance of: foreach vs for vs map vs for of

Created: 5 years ago by: Guest

Jump to the latest result

foreach

for

map

for of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):