Benchmark: findIndex vs. indexOf

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:

findIndex
var index = arr.findIndex( (item) => item.id === foo);
indexOf
var bar = { id: foo }; var index = arr.indexOf(bar);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
findIndex
indexOf

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'll dive into explaining the benchmark.

**What is being tested?**

The benchmark is comparing two methods to find an element in an array: `Array.prototype.indexOf()` and `Array.prototype.findIndex()`. Both methods are used to search for a specific value within the array, but they differ in how they handle the result.

**Options compared:**

1. **`indexOf()`**: This method returns the index of the first occurrence of the specified value, or -1 if it is not found.
2. **`findIndex()`**: This method returns the index of the first occurrence of the specified value, or -1 if it is not found.

**Pros and Cons:**

* `indexOf()`: Pros:
	+ More widely supported in older browsers (IE 8+).
	+ May be faster in cases where the element is found early in the array.
* `findIndex()`: Pros:
	+ Designed for use with promises, generators, or iterators, making it more flexible.
	+ Returns -1 if not found, which can be useful for handling such cases.

Cons:

* `indexOf()`: May be slower due to its search algorithm and additional checks.
* `findIndex()`: Can be slower for large arrays, as it has to iterate through the entire array to find a match.

**Library usage:**

None of the test cases use any libraries or external dependencies. The benchmark is purely focused on comparing the performance of these two methods within the Array prototype.

**Special JS feature/syntax:**

No special JavaScript features or syntax are used in this benchmark.

**Other alternatives:**

In addition to `indexOf()` and `findIndex()`, other methods can be used to search for an element in an array, such as:

* `Array.prototype.includes()` (introduced in ECMAScript 2015): Returns true if the array includes the specified value.
* Custom loop-based approaches using `for` loops or `forEach()`.

Keep in mind that these alternatives may have different performance characteristics and are not being tested in this benchmark.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:85.0) Gecko/20100101 Firefox/85.0

Browser/OS: Firefox 85 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
findIndex	7102.1 Ops/sec
indexOf	18982.9 Ops/sec

Related benchmarks:

findIndex vs. indexOf (version: 0)

Comparing performance of: findIndex vs indexOf

Created: 3 years ago by: Guest

Jump to the latest result

findIndex

indexOf

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):