Benchmark: Array.isArray vs truthy

Script Preparation code:

var a = [];
var b = ['1', '2'];
var c = undefined;
var d = [1,2,3];

Tests:

Array.isArray
Array.isArray(a)? 'true' : 'false';Array.isArray(b)? 'true' : 'false';Array.isArray(c)? 'true' : 'false';Array.isArray(d)? 'true' : 'false';
truthy
a ? 'true' : 'false';b ? 'true' : 'false';c ? 'true' : 'false';d ? 'true' : 'false';

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.isArray
truthy

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:144.0) Gecko/20100101 Firefox/144.0

Browser/OS: Firefox 144 on Windows

View result in a separate tab

Test name	Executions per second
Array.isArray	75351480.0 Ops/sec
truthy	128672928.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its test cases.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that compares two approaches:

1. `Array.isArray()`: This function checks if an object is an array using the `Array` constructor. It returns `true` if the object is an array, and `false` otherwise.
2. A truthy check: This approach uses a simple conditional statement to evaluate if a variable or expression is "truthy" (i.e., not falsy). In JavaScript, "falsy" values include `null`, `undefined`, `0`, `''`, `NaN`, etc.

**Options compared**

The two approaches are compared in the following test cases:

1. The first array `a` and an empty array literal `[]`.
2. The second array `b` and a string array `['1', '2']`.
3. An undefined variable `c`.
4. A regular array `d` with multiple elements.

**Pros and Cons of each approach**

**Array.isArray()**:

Pros:

* This method is explicit and clearly conveys the intention to check if an object is an array.
* It's often faster than a truthy check because it uses a specialized function for array checks.

Cons:

* The `Array` constructor can be slower in certain cases, such as when checking arrays with only one element or when dealing with very large arrays.

**Truthy check**

Pros:

* This approach is more concise and often faster due to the built-in nature of JavaScript's truthy checks.
* It's a more general-purpose method that can be applied to any type of variable or expression.

Cons:

* The behavior may not be immediately clear to some developers, especially those without extensive experience with JavaScript's semantics.
* This approach relies on the fact that in most cases, `false` values are considered falsy. However, there are edge cases where this might not hold true (e.g., when dealing with `NaN` or `Infinity`).

**Library**

In the provided benchmark definition code, no external libraries are explicitly used beyond JavaScript's built-in functions and variables.

However, the use of `Array.isArray()` relies on a library that provides the `Array` constructor. In modern JavaScript environments, this is typically part of the standard library (ECMAScript). If you were to write similar benchmarks in older browsers or environments without a functional `Array` constructor, you would need to use alternative methods, such as checking the `typeof` operator for the string `'array'`.

No special JavaScript features or syntax are used beyond the standard language.

Related benchmarks:

Array.isArray vs truthy (version: 0)

Comparing performance of: Array.isArray vs truthy

Created: 3 years ago by: Registered User

Jump to the latest result

Array.isArray

truthy

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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