Benchmark: js inarray - MeasureThat.net

Script Preparation code:

var A = {
	"X1": "X",
	"X2": "X",
	"X3": "X",
	"X4": "X",
	"X5": "X",
	"X6": "X",
	"X7": "X",
	"X8": "X",
	"X9": "X",
	"X10": "X"
};
var B = [ "X1", "X2", "X3", "X4", "X5", "X6", "X7", "X8", "X9", "X10" ];

Tests:

In
("X5" in A)
includes
B.includes("X5");
A
A["X5"]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
In
includes
A

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month 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 benchmark is designed to measure the performance of JavaScript strings checks. It tests three different approaches:

1. Using an array-like object (`A`) with string properties (e.g., `"X5" in A`)
2. Using the `includes()` method on an array (`B`) (e.g., `B.includes("X5")`)
3. Directly accessing a property of an object (`A["X5"]`)

**Options Compared**

* `in` vs. `includes()`: These two methods are used to check if a string is present in an array or array-like object. The main difference between them is that `in` checks for the presence of the value as a property name, whereas `includes()` checks for the presence of the value itself.
* Array-like object (`A`) vs. Direct access (`A["X5"]`): These two approaches differ in how they access and check the string properties.

**Pros and Cons**

1. **in** (using array-like object):
	* Pros:
		+ Works with arrays as well as array-like objects.
		+ Can be faster for large arrays since it avoids creating a new array or iterating over elements.
	* Cons:
		+ May require more memory to store the array-like object, especially if it's large.
		+ Can be slower for small arrays since it needs to iterate over elements to find the property name.
2. `includes()` (using an array):
	* Pros:
		+ Fast and efficient for both large and small arrays.
		+ Avoids iterating over elements, making it suitable for arrays with many null or undefined values.
	* Cons:
		+ Only works with arrays; not supported by all JavaScript engines for array-like objects.
3. Direct access (`A["X5"]`):
	* Pros:
		+ Fast and efficient since it directly accesses the property without iteration.
	* Cons:
		+ Requires the object to exist and have the property, which can lead to errors if not implemented correctly.

**Library/Language Feature**

There is no specific library used in this benchmark. However, some JavaScript engines (e.g., SpiderMonkey) may use optimized implementations for certain string checks.

**Special JS Features**

None mentioned explicitly. If you're interested in more advanced features like `forEach()`, `map()`, or `reduce()`, those are not specifically relevant to the performance comparison being tested here.

**Other Alternatives**

If you were looking for alternative approaches, some additional options could be:

* Using a `Map` object with string keys and values.
* Utilizing a `Set` object with string elements.
* Implementing a custom loop using `for...of` or `Array.prototype.forEach()` to iterate over the array or array-like object.

Keep in mind that these alternatives might not necessarily improve performance for this specific benchmark, as the focus is on comparing three basic approaches.

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Windows

View result in a separate tab

Test name	Executions per second
In	6704071.5 Ops/sec
includes	5947961.0 Ops/sec
A	6501256.0 Ops/sec

Related benchmarks:

js inarray (version: 0)

Comparing performance of: In vs includes vs A

Created: 6 months ago by: Guest

Jump to the latest result

In

includes

A

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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