Benchmark: Some vs. Filter vs. indexOf

Script Preparation code:

var hasZero = [];
var withoutZero = [];
for (var i = 0; i < 10000; i++) {
  hasZero.push(Math.floor(Math.random() * 1000));
  withoutZero.push(Math.floor(Math.random() * 1000) + 1)
}

Tests:

Array.some
var tempResult = !!Math.round(Math.random()) ? hasZero.some(v => v === 0) : withoutZero.some(v => v === 0);
Array.filter
var tempResult = !!Math.round(Math.random()) ? hasZero.filter(v => v === 0) : withoutZero.filter(v => v === 0);
Array.indexOf
var tempResult = !!Math.round(Math.random()) ? hasZero.indexOf(0) > -1 : withoutZero.indexOf(0) > -1;
Array.lastIndexOf
var tempResult = !!Math.round(Math.random()) ? hasZero.lastIndexOf(0) > -1 : withoutZero.lastIndexOf(0) > -1;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.some
Array.filter
Array.indexOf
Array.lastIndexOf

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 details of this JavaScript microbenchmarking test.

**What is being tested?**

The provided JSON represents a benchmark that compares three different approaches to filter or find an element in an array: `Array.some()`, `Array.filter()`, and `Array.indexOf()` (and its variant, `Array.lastIndexOf()`).

**Options being compared**

*   **`Array.some()`**: This method returns `true` if at least one element in the array passes the provided test. It stops iterating over the array as soon as it finds a match.
*   **`Array.filter()`**: This method creates a new array with all elements that pass the provided test.
*   **`Array.indexOf()`** and **`Array.lastIndexOf()`**: These methods return the index of the first occurrence of the specified element in the array. If the element is not found, they return -1.

**Pros and Cons**

*   **`Array.some()`**:
    *   Pros: Stops iterating over the array as soon as it finds a match, which can be beneficial for large arrays.
    *   Cons: Returns `true` even if no elements pass the test, whereas `filter()` returns an empty array if no elements pass the test.
*   **`Array.filter()`**:
    *   Pros: Returns a new array with all matching elements, making it suitable for situations where you need to keep the original data.
    *   Cons: Creates a new array and can be less efficient than `some()` or `indexOf()` for large arrays.
*   **`Array.indexOf()`** and **`Array.lastIndexOf()`**:
    *   Pros: Fast and efficient, as they only iterate over the array until they find the element.
    *   Cons: May return -1 if the element is not found, which can be inconvenient in some cases. They also require knowing the index of the desired element.

**Library**

In this benchmark, `Math.random()` is used to generate random numbers for testing purposes. This function returns a random number between 0 (inclusive) and 1 (exclusive).

**Special JS feature or syntax**

None mentioned explicitly in the provided code, but some of these methods are considered "old-school" approaches that may be less efficient or have different behavior compared to newer JavaScript features.

**Other alternatives**

*   **`Array.prototype.every()`**: This method returns `true` if all elements in the array pass the test. It stops iterating over the array as soon as it finds an element that doesn't pass the test.
*   **`Array.prototype.map()`**, **`Array.prototype.reduce()`**, and other higher-order functions: These methods can also be used to filter or transform arrays, but they might not be as straightforward or efficient as the methods being compared in this benchmark.

For a wide range of software engineers, understanding these basic array methods and their trade-offs is essential for writing efficient and effective JavaScript code.

Related benchmarks:

Some vs. Filter vs. indexOf (version: 0)

Comparing performance of: Array.some vs Array.filter vs Array.indexOf vs Array.lastIndexOf

Created: 8 years ago by: Guest

Jump to the latest result

Array.some

Array.filter

Array.indexOf

Array.lastIndexOf

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):