Benchmark: map+filter options

HTML Preparation code:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.core.js"></script>

Script Preparation code:

var arr = (new Array(1000)).map((_, i) => i);

Tests:

naive map + filter
var result = arr.map((x) => x % 2 === 0 ? x : null).filter(x => x !== null);
manual for loop
var result = []; for (var i = 0; i < arr.length; i++) { var x = arr[i]; if (x % 2 === 0) { result.push(x); } }
manual for loop fixed size result
var result = new Array(arr.length); var next = 0; for (var i = 0; i < arr.length; i++) { var x = arr[i]; if (x % 2 === 0) { result[next++] = x; } } result = result.slice(0, next);
foreach
var result = []; arr.forEach((x) => { if (x % 2 === 0) { result.push(x); } });
for of
var result = []; for (var x of arr) { if (x % 2 === 0) { result.push(x); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
naive map + filter
manual for loop
manual for loop fixed size result
foreach
for of

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript benchmarks.

**Benchmark Overview**

The provided JSON represents a benchmark test case on MeasureThat.net, which measures the performance of different approaches for filtering an array in JavaScript. The test creates an array of 1000 elements and applies various filters to extract even numbers. The benchmark defines four test cases:

1. Naive map + filter
2. Manual for loop
3. Manual for loop with fixed-size result
4. foreach
5. For of

**Options Compared**

The test compares the performance of five different approaches:

1. **Naive map + filter**: Using the `map()` method to create a new array and then filtering it using another `filter()` method.
2. **Manual for loop**: Using a traditional for loop with conditional statements to iterate over the array and push even numbers into a result array.
3. **Manual for loop fixed size result**: Similar to manual for loop, but uses a fixed-size result array to avoid unnecessary allocations.
4. **foreach**: Using the `forEach()` method to iterate over the array and filter out odd numbers.
5. **For of**: Using a for-of loop with an iterator to iterate over the array and filter out odd numbers.

**Pros and Cons**

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

*   **Naive map + filter**: Pros: Simple, readable code. Cons: Creates two arrays (a new one for mapping and another for filtering), which can lead to performance issues.
*   **Manual for loop**: Pros: Low overhead, straightforward implementation. Cons: Requires manual iteration over the array, which can be error-prone and slow for large datasets.
*   **Manual for loop fixed size result**: Similar pros and cons as manual for loop, but avoids unnecessary allocations by using a fixed-size result array.
*   **foreach**: Pros: Cleaner code, no need to manually iterate over the array. Cons: May not be as fast as manual loops or optimized foreach implementations.
*   **For of**: Pros: Cleanest and most modern implementation. Cons: Requires support for for-of loops in older browsers.

**Library and Special JS Features**

The test uses Lodash.js, a popular utility library for JavaScript. It provides the `map()` method, which is used in the "naive map + filter" approach.

There are no special JS features or syntax mentioned in this benchmark.

**Other Alternatives**

If you're looking for alternative approaches to filtering arrays, here are some other options:

*   **Using Array.prototype.filter()**: A concise and readable way to filter arrays using a single method.
*   **Using Array.prototype.reduce()**: Another powerful method for array manipulation that can be used for filtering.
*   **Using modern functional programming techniques**: Methods like `filter()` and `map()` are often used in conjunction with higher-order functions and callback functions.

In conclusion, the benchmark test case provides a thorough comparison of different approaches to filtering arrays in JavaScript. By understanding the pros and cons of each approach, developers can choose the most suitable method for their specific use cases and optimize their code for better performance.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser/OS: Firefox 115 on Ubuntu

View result in a separate tab

Test name	Executions per second
naive map + filter	442473.5 Ops/sec
manual for loop	1387733.1 Ops/sec
manual for loop fixed size result	758541.6 Ops/sec
foreach	1219165.4 Ops/sec
for of	210226.0 Ops/sec

Related benchmarks:

map+filter options (version: 0)

Comparing performance of: naive map + filter vs manual for loop vs manual for loop fixed size result vs foreach vs for of

Created: one year ago by: Guest

Jump to the latest result

naive map + filter

manual for loop

manual for loop fixed size result

foreach

for of

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):