Benchmark: Array isArray vs instanceof vs isEqual vs isLessThan

Script Preparation code:

var test = [1,2,3,4];
var c;

Tests:

Instanceof
if (test[0] instanceof Array) { c++; }
isArray
if (Array.isArray(test[0])) { c++; }
isEqual
if (test[0] === 'a') { c++; }
isLessThan
if(test[0] < -1) { c++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Instanceof
isArray
isEqual
isLessThan

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36

Browser/OS: Chrome 83 on Windows

View result in a separate tab

Test name	Executions per second
Instanceof	4104010.5 Ops/sec
isArray	4019264.2 Ops/sec
isEqual	11114933.0 Ops/sec
isLessThan	10960205.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

**Benchmark Definition**

The benchmark definition provides information about the test case, including its name and description. In this case, the test case is comparing four different methods to check if an element is of a specific type or value:

* `isArray`: checks if an element is an array using the `Array.isArray()` method.
* `instanceof`: checks if an element is of a specific constructor (e.g., `Array`) using the `instanceof` operator.
* `isEqual`: checks if two values are equal using the `===` operator.
* `isLessThan`: checks if one value is less than another using the `<` operator.

**Script Preparation Code**

The script preparation code sets up a test array `test` with four elements: `[1, 2, 3, 4]`.

**Html Preparation Code**

There is no HTML preparation code provided, which means that the benchmark does not generate any user interface or input to be processed by the JavaScript engine.

**Test Cases**

The individual test cases are defined as a JSON array. Each object in the array contains the following properties:

* `Benchmark Definition`: the actual JavaScript code that will be executed.
* `Test Name`: a descriptive name for each test case (e.g., "Instanceof").

Let's analyze each test case:

1. `if (test[0] instanceof Array) { c++; }`:
	* This test case uses the `instanceof` operator to check if the first element of the `test` array is an instance of the `Array` constructor.
	* The purpose of this test case is to measure the performance of using the `instanceof` operator compared to other methods.
2. `if (Array.isArray(test[0])) { c++; }`:
	* This test case uses the `Array.isArray()` method to check if the first element of the `test` array is an array.
	* The purpose of this test case is to measure the performance of using the `Array.isArray()` method compared to other methods.
3. `if (test[0] === 'a') { c++; }`:
	* This test case uses the `===` operator to check if the first element of the `test` array is equal to the string `'a'`.
	* The purpose of this test case is to measure the performance of using the `===` operator compared to other methods.
4. `if (test[0] < -1) { c++; }`:
	* This test case uses the `<` operator to check if the first element of the `test` array is less than `-1`.
	* The purpose of this test case is to measure the performance of using the `<` operator compared to other methods.

**Library Used**

In two test cases, a variable `c` is used. This variable is not defined in the benchmark definition, but it is likely that the benchmark is using a global variable or a function that returns a value and assigns it to `c`.

In the `Array.isArray()` method, the `Array.isArray()` function is called with the first element of the `test` array as an argument. This function is part of the ECMAScript standard and is used to check if an object is an array.

**Special JS Feature**

There are no special JavaScript features or syntax mentioned in the benchmark definition.

**Other Alternatives**

Some alternative methods for checking types or values in JavaScript include:

* Using a `switch` statement or a `case` clause with a specific value.
* Using a regular expression to match a pattern.
* Using a function that takes an argument and returns a boolean value indicating whether it matches the expected type or value.

However, these alternatives are not being tested in this benchmark.

Related benchmarks:

Array isArray vs instanceof vs isEqual vs isLessThan (version: 0)

Comparing performance of: Instanceof vs isArray vs isEqual vs isLessThan

Created: 4 years ago by: Guest

Jump to the latest result

Instanceof

isArray

isEqual

isLessThan

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):