Benchmark: Array loop vs foreach vs map 22222122

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 (const item of arr) { someFn(item); }

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 llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is being tested?**

The provided benchmark tests the performance of three different approaches to iterate over an array in JavaScript:

1.  **For loop**: A traditional for loop that uses a manual counter (`var i = 0;` and `i < len;`) to iterate over the array elements.
2.  **ForEach loop**: The `forEach` method, which is a built-in method of arrays in JavaScript. It executes a provided function once for each element in the array.
3.  **Map method**: The `map` method, another built-in method of arrays that applies a specified function to every element of the array.

**Options comparison**

The benchmark compares the performance of these three approaches:

*   For loop: manual iteration using a counter
*   ForEach loop: using the built-in `forEach` method
*   Map method: using the built-in `map` method

**Pros and Cons:**

1.  **For loop**: This approach provides direct access to array elements and allows for fine-grained control over the iteration process.
    *   Pros:
        *   Flexibility in iterating over arrays
        *   Easy to understand and implement
    *   Cons:
        *   Requires manual counter management, which can lead to errors
        *   Less efficient than using built-in methods (forEach and map)
2.  **ForEach loop**: This approach is concise and easy to read, as it leverages the built-in `forEach` method.
    *   Pros:
        *   Concise and readable code
        *   Built-in functionality reduces errors
    *   Cons:
        *   Less flexible than a for loop (cannot directly access array elements)
3.  **Map method**: This approach provides an elegant way to transform arrays using the `map` method.
    *   Pros:
        *   Concise and readable code
        *   Built-in functionality reduces errors
    *   Cons:
        *   Less control over iteration compared to a for loop

**Special considerations**

*   **Arrow functions**: In the provided benchmark, arrow functions (`(item) => someFn(item)` in `map`) are used. Arrow functions provide a concise way to define small functions and avoid the `this` context issue.
*   **JavaScript version**: Although not explicitly stated, the benchmark is likely written for modern JavaScript versions (ECMAScript 2015 or later), which introduced the `for...of` loop.

**Other alternatives**

In addition to these three approaches, other methods could be used to iterate over arrays in JavaScript:

1.  **While loop**: A traditional while loop that uses a manual counter.
2.  **For...of loop**: A more modern iteration approach that provides direct access to array elements and is concise.
3.  **Lodash functions**: Lodash is a popular utility library for JavaScript, providing various iteration functions like `forEach`, `map`, and others.

Note that the choice of iteration method depends on the specific use case, performance requirements, and personal preference.

In conclusion, MeasureThat.net's benchmark provides an excellent opportunity to explore the performance differences between various array iteration methods in JavaScript.

Related benchmarks:

Array loop vs foreach vs map 22222122 (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 llama3.2:3b, generated one year ago):