Benchmark: object[]: findIndex vs for loop

Script Preparation code:

var len = 1000
var arr = Array.from({length: 1000},(_,i) => ({id: i}));
var foo = Math.floor(Math.random() * len);

Tests:

findIndex
arr.findIndex((itm) => itm.id > foo);
for loop
for (let i = 0; i < arr.length; i++) { if (arr[i].id > foo) break; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
findIndex
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.54 Safari/537.36

Browser/OS: Chrome 95 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
findIndex	666686.0 Ops/sec
for loop	238970.7 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON to understand what is being tested.

**Benchmark Description**

The benchmark compares two approaches to find the index of an element in an array:

1. `Array.prototype.findIndex` with a callback function that returns `true` when the condition `itm.id > foo` is met.
2. A traditional `for` loop over the array, checking each element's `id` property and breaking out of the loop when the condition is met.

**Options Compared**

The benchmark tests two options:

1. **Array.prototype.findIndex**: This method is a built-in JavaScript function that returns the index of the first element in an array that satisfies the provided condition. It is more concise and expressive than a traditional `for` loop.
2. **Traditional for loop**: A classic, straightforward approach to finding the index of an element in an array. While it may not be as readable or concise as the `findIndex` method, it can be useful in certain situations where performance is critical.

**Pros and Cons**

**Array.prototype.findIndex**

Pros:

* More concise and expressive
* Less prone to errors due to its explicit nature
* May be faster for large arrays since it only iterates over the elements that match the condition

Cons:

* Requires a callback function, which can add complexity if not used carefully
* May not work as expected in certain situations (e.g., when dealing with null or undefined values)

**Traditional for loop**

Pros:

* Easy to understand and implement
* Does not require a callback function
* Can be more suitable for debugging purposes

Cons:

* More verbose and prone to errors due to the need to manually increment an index variable
* May iterate over all elements in the array even if the condition is met, leading to unnecessary work

**Other Considerations**

The benchmark uses JavaScript as the programming language and tests on a relatively small array size (1000 elements). The results will likely vary depending on the specific use case, such as:

* Larger array sizes: `findIndex` might still be faster due to its more efficient iteration strategy.
* Complex conditions: A traditional `for` loop might be preferred for readability and maintainability.

**Library Used**

In this benchmark, no libraries are explicitly mentioned. However, it's possible that the JavaScript engine used by the browser (e.g., V8 in Chrome) provides some built-in optimizations or features that affect the performance of these two approaches.

**Special JS Feature/Syntax**

There is no specific JavaScript feature or syntax being tested here. Both options use standard JavaScript concepts and are easily recognizable to experienced developers.

**Alternatives**

Other alternatives for finding an index in an array could include:

* Using `Array.prototype.indexOf` instead of `findIndex`. This method returns the index of the first element that satisfies the condition, but it may return -1 if no element matches.
* Implementing a custom binary search algorithm to find the index of an element in an array. This approach is more efficient for large arrays but can be complex to implement.
* Using a library like Lodash (e.g., `lodash.indexOf`) or a framework like React (e.g., `useMemo` with `Array.prototype.findIndex`) to simplify and optimize this type of operation.

Keep in mind that the choice of implementation depends on the specific use case, performance requirements, and personal preference.

Related benchmarks:

object[]: findIndex vs for loop (version: 0)

Testing Array.prototype.findIndex vs a for loop over an array of objects

Comparing performance of: findIndex vs for loop

Created: 3 years ago by: Registered User

Jump to the latest result

findIndex

for loop

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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