Benchmark: map vs findIndex v2

Script Preparation code:

var arr = new Array(15000);
arr.fill({ id: 0 });
arr = arr.map((el, idx) => el.id = idx);
var foo = Math.floor(Math.random() * 15000);

Tests:

map
let new_a = {id: foo, new_a: true}; arr = arr.map(a => (a.id === foo ? new_a : a));
findIndex
let new_a = {id: foo, new_a: true}; let i = arr.findIndex(a => a.id = foo); arr[i] = new_a;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
findIndex

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.102 Safari/537.36

Browser/OS: Chrome 85 on Windows

View result in a separate tab

Test name	Executions per second
map	576.2 Ops/sec
findIndex	2745279.2 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 benchmark json and explain what's being tested.

**What is being tested?**

The benchmark compares two approaches for replacing elements in an array: `map()` and `findIndex()`. The test case uses JavaScript, specifically the V8 engine used by Google Chrome.

**Options compared:**

* `map()`: A built-in JavaScript method that creates a new array with the results of applying a provided function on every element in this array.
* `findIndex()`: A built-in JavaScript method that returns the index of the first element in an array that satisfies the provided testing function.

**Pros and Cons:**

* **map():**
	+ Pros:
		- Faster execution time due to its optimized implementation in V8.
		- Can be used for mapping multiple values at once, not just replacing one value.
	+ Cons:
		- Creates a new array, which can lead to increased memory usage.
		- May have additional overhead due to the creation of the new array.
* `findIndex():`
	+ Pros:
		- More memory-efficient since it only replaces the original element, rather than creating a new array.
		- Can be more cache-friendly due to its indexing-based approach.
	+ Cons:
		- Slower execution time compared to `map()` due to its indexing and conditional checks.

**Library/Function used:**

* `Array.prototype.map()`: A built-in JavaScript method that is part of the Array prototype. It's implemented in V8, which means it's optimized for performance.
* `Array.prototype.findIndex()`: A built-in JavaScript method that is also part of the Array prototype.

**Special JS feature/syntax:**

There is no specific JavaScript feature or syntax used in this benchmark. The focus is solely on comparing two different array replacement methods.

**Other alternatives:**

For replacing elements in an array, other approaches could include:

* Using `forEach()`: While not as optimized as `map()` and `findIndex()`, `forEach()` can still be a viable option for simple use cases.
* Using manual indexing and iteration: This approach would require more code and manual management of the index, but could potentially offer good performance if optimized correctly.

Keep in mind that these alternatives might have different trade-offs regarding execution time, memory usage, and code complexity.

Related benchmarks:

map vs findIndex v2 (version: 0)

Comparing performance of: map vs findIndex

Created: 4 years ago by: Guest

Jump to the latest result

map

findIndex

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):