Benchmark: For i / For of / ForEach

Script Preparation code:

var testingArray = new Array(1000).fill(1);

Tests:

For i
const newArr = []; for (let i = 0, item; (item = testingArray[i]); i += 1) { newArr.push(item); }
For of
const newArr = []; for (const item of testingArray) { newArr.push(item); }
ForEach
const newArr = []; testingArray.forEach(item => { newArr.push(item); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
For i
For of
ForEach

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.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

MeasureThat.net provides a platform for users to create and run JavaScript microbenchmarks. In this case, we're interested in understanding what options are compared, their pros and cons, and other considerations when it comes to iterating over arrays using `for`, `for...of`, and `forEach`.

The benchmark definition JSON provides the following information:

*   Three test cases: "For i", "For of", and "ForEach"
*   A script preparation code that creates a testing array with 1000 elements filled with the value 1
*   An optional HTML preparation code (not used in this case)

**Options being compared**

The three test cases are designed to compare different approaches for iterating over arrays:

1.  **"For i"**: This approach uses a traditional `for` loop to iterate over the array, where the loop variable is declared and updated manually.
2.  **"For of"**: This approach utilizes the `for...of` loop, which allows for more concise and readable code for iterating over arrays.
3.  **"ForEach"**: This approach uses the `forEach` method, which is a part of the Array prototype and provides a more functional programming-style way to iterate over arrays.

**Pros and cons of each approach**

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

*   **For i**
    *   Pros:
        *   More control over iteration variables
        *   Potential for better performance in some cases (due to manual loop optimization)
    *   Cons:
        *   Less readable code
        *   Requires more boilerplate code
*   **For of**
    *   Pros:
        *   More concise and readable code
        *   Easier to maintain and update
    *   Cons:
        *   May have slower performance due to the overhead of the `for...of` loop
*   **ForEach**
    *   Pros:
        *   Most concise and readable code among the three options
        *   Easy to understand and maintain
    *   Cons:
        *   Potential for slower performance due to the overhead of the `forEach` method

**Library used:**

In this benchmark, there is no explicit library mentioned. However, it's worth noting that some browsers may have internal optimizations or extensions that could affect performance. For example, modern browsers like Chrome and Firefox have built-in support for `for...of` loops and `forEach` methods.

**Special JS feature or syntax:**

There are no special JavaScript features or syntax used in this benchmark. The focus is on the iteration mechanisms (looping and array methods) rather than any specific language features.

**Other alternatives:**

If you're interested in exploring alternative approaches, here are a few options:

*   **Array.prototype.every()**: This method iterates over an array and returns `true` if all elements pass the test.
*   **Array.prototype.some()**: This method iterates over an array and returns `true` if at least one element passes the test.
*   **Arrow functions**: These provide a concise way to define small, single-purpose functions that can be used in place of traditional `function` declarations.

Keep in mind that these alternatives may not directly address the same iteration concerns as the original benchmark, but they do offer alternative approaches for working with arrays.

Related benchmarks:

For i / For of / ForEach (version: 1)

Comparing performance of: For i vs For of vs ForEach

Created: 5 years ago by: Registered User

Jump to the latest result

For i

For of

ForEach

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):