Benchmark: includes indexOf

Script Preparation code:

var a = [...Array(200000)].map((_, i) => i)

Tests:

includes
a.includes(100000)
indexOf
a.indexOf(100000) !== -1

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
includes
indexOf

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 benchmark being tested on MeasureThat.net.

**Benchmark Definition and Script Preparation Code**

The benchmark definition is a JSON object that specifies the script preparation code and the HTML preparation code (which is empty in this case). The script preparation code is:

`var a = [...Array(200000)].map((_, i) => i);`

This code creates an array of 200,000 elements, where each element is the current index `i`. This is done to create a large array that can be searched efficiently.

The purpose of this code is to create a large data structure that can be used to test the performance of various JavaScript methods on arrays.

**Individual Test Cases**

There are two individual test cases:

1. **includes**: The benchmark definition is `a.includes(100000)`.
This method checks if the array `a` contains the value 100,000. The `includes()` method is a modern JavaScript method that was introduced in ECMAScript 2019 (ES9). It's faster and more efficient than traditional methods like `indexOf()`, but it's also less predictable, as its behavior can be affected by the order of elements in the array.

2. **indexOf**: The benchmark definition is `a.indexOf(100000) !== -1`.
This method finds the index of the first occurrence of 100,000 in the array `a`. If the value is not found, it returns `-1`.

**Library and Purpose**

In both test cases, the array data structure is created using the `Array` constructor and a map function. The library used here is the built-in JavaScript Array library.

There are no external libraries used in this benchmark.

**JavaScript Feature/Syntax Used**

The `includes()` method is used, which is a modern JavaScript feature introduced in ECMAScript 2019 (ES9).

Other alternatives to these methods could be:

* Using the traditional `indexOf()` method.
* Using a library like Lodash's `includes` function.
* Writing custom loop-based code to find the index of an element.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **includes() method**: Pros:
	* Fast and efficient
	* Easy to use and understand
Cons:
	* Can be unpredictable due to array order effects
2. **indexOf() method**: Pros:
	* Predictable behavior
Cons:
	* Slower than `includes()`
3. **Custom loop-based code**: Pros:
	* More predictable behavior
Cons:
	* Slower and more complex

**Other Considerations**

When testing the performance of these methods, it's essential to consider factors like:

* Cache locality: How does the array's structure affect the cache?
* Branch prediction: Can we predict which branch will be taken in the execution?
* Loop unrolling: How can we optimize loops for better performance?

By understanding these factors and considering alternative approaches, we can gain a deeper insight into how to optimize JavaScript code for performance.

Related benchmarks:

includes indexOf (version: 0)

Comparing performance of: includes vs indexOf

Created: 2 years ago by: Guest

Jump to the latest result

includes

indexOf

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):