Benchmark: findIndex versus map

Script Preparation code:

var playlist = [];
for (let i=0; i<1000; i++){
  playlist.push({title: "", artist: "", src:`/${i}`});
}

Tests:

findIndex
var index = playlist.findIndex(item => item.src === "/450"); playlist[index] = { title: 'b', artist:"b", src: "/450"};
map
var arr = playlist.map(item => { if(item.src === "/450"){ return { title: 'b', artist:"b", src: "/450"}; } return item; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
findIndex
map

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser/OS: Chrome 110 on Windows

View result in a separate tab

Test name	Executions per second
findIndex	147967.9 Ops/sec
map	34450.2 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what's being tested in this JavaScript microbenchmark.

**Benchmark Definition**

The benchmark is designed to compare the performance of two different approaches:

1. Using `findIndex` method: This method searches for an element that satisfies a specified condition and returns its index.
2. Using `map` function: This function creates a new array with the results of applying a provided function on every element in this array.

**Options Compared**

The benchmark is comparing the execution time of these two approaches:

* `findIndex` method with a callback function that checks if the `src` property of each object matches a specific value (`"/450"`).
* `map` function with an arrow function that performs a similar check on each object.

**Pros and Cons**

Here are some pros and cons of each approach:

* **findIndex**:
	+ Pros: More concise and efficient way to find the first element matching a condition.
	+ Cons: May be slower if the array is very large, as it requires a linear search.
* **map**:
	+ Pros: Can be faster for large arrays, as it avoids the overhead of searching for an index.
	+ Cons: Creates a new array with modified elements, which can lead to memory allocation issues.

**Library/Functionality Used**

In both benchmark cases, the `findIndex` method is used from the native JavaScript API. The `map` function is also part of the native JavaScript API.

No external libraries or frameworks are required for this benchmark.

**Special JS Feature/Syntax**

Neither of the benchmark cases uses any special JavaScript features or syntax that would require additional explanation.

**Other Alternatives**

If you were to rewrite these benchmarks using alternative approaches, here are some possibilities:

* Instead of `findIndex`, you could use a regular loop with an index variable:
```javascript
for (let i = 0; i < playlist.length; i++) {
  if (playlist[i].src === "/450") {
    // do something
  }
}
```
* Instead of `map`, you could use a custom function to create a new array:
```javascript
const resultArray = [];
for (let i = 0; i < playlist.length; i++) {
  if (playlist[i].src === "/450") {
    resultArray.push({ title: 'b', artist: "b", src: "/450" });
  } else {
    resultArray.push(playlist[i]);
  }
}
```
These alternatives would not be considered benchmark cases, as they would likely have different performance characteristics and might not even test the same aspects of the `findIndex` and `map` functions.

In summary, this benchmark compares the execution time of two common ways to achieve a similar result: using `findIndex` versus using `map`. The results can help identify which approach is faster and more suitable for specific use cases.

Related benchmarks:

findIndex versus map (version: 0)

Testing findIndex and map on an array of object

Comparing performance of: findIndex vs map

Created: one year ago by: Registered User

Jump to the latest result

findIndex

map

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):