Benchmark: for loop vs findIndex

Script Preparation code:

var arr = [];
var i = 0;

while (i <= 1E5) arr[i] = i++;

Tests:

for loop
let index; for (let i = 0; i < arr.length; i++) { if (arr[i] === 1E5) { index = i; break; } }
Array.prototype.findIndex
const index = arr.findIndex(item => item == 1E5);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop
Array.prototype.findIndex

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided JSON benchmark and explain what is being tested, compared, and some of the pros and cons of different approaches.

**Benchmark Definition**

The benchmark measures which approach is faster: using a traditional `for` loop to find the index of an element in an array (`arr`) or using the `Array.prototype.findIndex()` method. The script preparation code initializes an empty array `arr` and populates it with values from 0 to 100,000.

**Comparison Options**

The two options being compared are:

1. **Traditional `for` loop**: This approach uses a manual loop to iterate through the array and checks each element until it finds the desired value (in this case, 100,000). This method is more verbose but provides full control over the iteration process.
2. **`Array.prototype.findIndex()`**: This method returns the index of the first element that satisfies the provided callback function. In this case, the callback function checks if the current element is equal to 100,000.

**Pros and Cons**

* **Traditional `for` loop**:
	+ Pros: provides full control over the iteration process, can be more efficient for certain use cases.
	+ Cons: can be verbose, prone to errors (e.g., off-by-one errors), and may not work well with large datasets.
* **`Array.prototype.findIndex()`**:
	+ Pros: concise, easy to read, and maintainable. Also, modern browsers have optimized this method for performance.
	+ Cons: relies on the browser's implementation, which might be less efficient in certain cases.

**Library/Functionality Used**

In this benchmark, `Array.prototype.findIndex()` is used as a library function provided by the JavaScript language standard. This means that any compliant JavaScript engine (including browsers and Node.js) must support this method for the test to run.

**Special JS Features/Syntax**

The only notable feature used in this benchmark is the use of the `let` keyword, which was introduced in ECMAScript 2015 (ES6). The `const` keyword is also used, but its functionality is similar to `let`. No other special features or syntax are present.

**Alternatives**

Other alternatives for finding an element's index in an array include:

* Using the `indexOf()` method (which returns -1 if not found)
* Using a regular expression with the `String.prototype.indexOf()` method
* Using a manual loop similar to the traditional `for` loop approach

However, these alternatives may have varying levels of performance, readability, and maintainability compared to the `Array.prototype.findIndex()` method.

**Benchmark Preparation Code**

The script preparation code initializes an empty array `arr` and populates it with values from 0 to 100,000 using a while loop. This ensures that the array has a large enough size for the benchmark to be meaningful.

**Individual Test Cases**

The individual test cases are defined as separate benchmark definitions, each representing one of the two options being compared:

* "for loop" uses a traditional `for` loop to find the index of 100,000 in the populated array.
* "Array.prototype.findIndex()" uses the `Array.prototype.findIndex()` method with a callback function that checks if the current element is equal to 100,000.

The test results show which approach is faster for this specific benchmark.

Related benchmarks:

for loop vs findIndex (version: 0)

Measuring which is faster

Comparing performance of: for loop vs Array.prototype.findIndex

Created: 3 years ago by: Guest

Jump to the latest result

for loop

Array.prototype.findIndex

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):