Benchmark: JS findIndex vs forEach

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
arr.findIndex((itm) => itm.id === foo);
forEach
arr.forEach((value) => value.id === foo);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
findIndex
forEach

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking test case that compares the performance of two approaches:

1. `arr.findIndex((itm) => itm.id === foo)`
2. `arr.forEach((value) => value.id === foo)`

**What's being tested?**

These two approaches are being compared in terms of their execution speed, measured in executions per second (EPS).

**Options Compared**

The two options are:

1. **`findIndex`**: This method returns the index of the first element in the array that satisfies the provided condition (`itm.id === foo`). If no such element is found, it returns -1.
2. **`forEach`**: This method iterates over each element in the array and executes the provided callback function for each element.

**Pros and Cons**

### `findIndex`

Pros:

* Typically faster than `forEach` because it only searches for the first match, which reduces the number of iterations.
* Returns a specific value (index) if found, which can be useful in certain scenarios.

Cons:

* May not return any meaningful result if no element is found.
* Can throw an error if the callback function is not provided or throws an error.

### `forEach`

Pros:

* Always iterates over all elements in the array, making it more predictable and easier to understand.
* Returns nothing (void) if no element is found.

Cons:

* Typically slower than `findIndex` because it searches for every element in the array.
* Not as efficient when dealing with large arrays or complex data structures.

**Library/External Functionality**

Neither of these options relies on an external library. However, if you were to use a library like Lodash (a popular utility library for JavaScript), you might see implementations that use `findIndex` or `forEach` internally. But in this specific benchmark, only vanilla JavaScript is used.

**Special JS Features/Syntax**

Neither of these options utilizes any special JavaScript features or syntax. They are basic, standard JavaScript methods.

**Other Alternatives**

If you're looking for alternative approaches to find an element in an array:

* `filter()`: Returns a new array with all elements that pass the test implemented by the provided function.
* `reduce()`: Accumulates a value on each element of the array (from left-to-right) so as to reduce it to a single output value.

However, these alternatives may not be as efficient or straightforward as `findIndex` and `forEach`, respectively.

Related benchmarks:

JS findIndex vs forEach (version: 0)

Comparing performance of: findIndex vs ForEach

Comparing performance of: findIndex vs forEach

Created: 2 years ago by: Guest

Jump to the latest result

findIndex

forEach

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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