Benchmark: For each vs some

Script Preparation code:

var array = new Array(100);

Tests:

forEach
array.forEach(function(item, index) { array[i]; });
some
array.some(function(item, index) { array[i]; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
some

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 on MeasureThat.net.

**What is being tested?**

The provided JSON represents two individual test cases: `forEach` and `some`. These test cases aim to measure the performance difference between using the `forEach` loop and the `some` loop when iterating over an array.

In essence, both loops are attempting to access elements in the same array (`array`) using their respective indices (`i`). However, there's a crucial difference:

*   The `forEach` loop uses `for...of` or `Array.prototype.forEach()` (in older browsers), which automatically iterates over each element of an iterable object (like an array) and executes the callback function once for each element.
*   The `some` loop uses `Array.prototype.some()` (introduced in ECMAScript 2015, aka ES6). This method returns a boolean value indicating whether at least one element in the array passes the test implemented by the provided function.

**Options compared**

There are two primary approaches being compared:

1.  **For each vs Some Loop**: The main difference lies in how they access elements within the array.
2.  **Execution speed**: MeasureThat.net is primarily focused on comparing execution speeds between these two loop types, as this can impact performance-critical code.

**Pros and Cons of different approaches**

*   **For Each Loop (forEach)**:
    *   Pros:
        -   More intuitive for developers who are accustomed to the traditional `for` loop syntax.
        -   Faster for arrays with a small number of elements due to its simplicity and lack of overhead.
    *   Cons:
        -   Has performance limitations when dealing with very large arrays, as it involves unnecessary iterations (e.g., checking each element even if one has already passed the test).
*   **Some Loop**:
    *   Pros:
        -   Optimized for large arrays by terminating early and avoiding unnecessary iterations.
    *   Cons:
        -   May be less familiar to developers not used to ES6 syntax.

**Library**

The `some` loop in JavaScript uses the built-in `Array.prototype.some()` method, which is implemented in modern browsers (from around 2015 onwards) or via polyfills for older browsers. This method relies on the ECMAScript standard to provide a standardized way of performing this kind of iteration.

**Special JS feature/syntax**

There's no special JavaScript feature or syntax mentioned here; however, `some` loop and `forEach` are both relatively new and important concepts introduced by ES6 (JavaScript 2015), which changed how the browser interpreted these iterations, improving performance.

Related benchmarks:

For each vs some (version: 0)

Testing for each vs some

Comparing performance of: forEach vs some

Created: 9 years ago by: Guest

Jump to the latest result

forEach

some

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):