Benchmark: check if obj is null or undefined

Script Preparation code:

var obj = window.ololo;

Tests:

not obj
var isNullOrUndefined = !obj
obj is null or obj is undefined
var isNullOrUndefined = obj === null || obj === undefined;
type of obj is undefined or obj is null
var isNullOrUndefined = typeof obj === 'undefined' || obj === null;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
not obj
obj is null or obj is undefined
type of obj is undefined or obj is null

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The benchmark measures how fast three different approaches can determine if an object `obj` is null or undefined in JavaScript. The benchmark uses a simple script preparation code that assigns `obj` to the global scope (`window.ololo`) and then defines three different functions to test for nullity.

**Approach 1: Using the Not Equal Operator (!)**

```javascript
var isNullOrUndefined = !obj;
```

Pros:

* Simple and straightforward.
* Easy to read and understand.

Cons:

* This approach uses the not equal operator, which can be misleading because it actually checks if `obj` is falsy (i.e., null or undefined). If you're used to thinking of `null` as falsey in a certain context, this might lead to unexpected behavior.
* The `!` operator has higher precedence than the equality operators, so it's essential to use parentheses around the expression for clarity.

**Approach 2: Using a Conditional Expression**

```javascript
var isNullOrUndefined = obj === null || obj === undefined;
```

Pros:

* Clearly conveys the intent of checking if `obj` is either null or undefined.
* Avoids potential issues with the not equal operator.

Cons:

* Slightly less readable than Approach 1, as it uses two consecutive equality checks.
* May be slower due to the additional checks required by the conditional expression.

**Approach 3: Using a Type Check**

```javascript
var isNullOrUndefined = typeof obj === 'undefined' || obj === null;
```

Pros:

* Clearly separates type checking from value checking.
* Can be more efficient than Approach 1 or 2, as it only checks the type of `obj`.

Cons:

* May lead to unexpected behavior if you're not familiar with the `typeof` operator. The `undefined` keyword has a specific meaning in JavaScript that might not be immediately apparent.
* Less readable than Approach 1 or 2, due to the use of `typeof` and the wordy condition.

**Library: Window**

The benchmark uses the global `window` object as a variable for `obj`. This is a common convention in JavaScript development. The `window` object provides access to various attributes and methods related to the browser environment, including the DOM and APIs.

**Special JS Feature: No Specific Features Mentioned**

There are no special JavaScript features or syntaxes explicitly mentioned in this benchmark. However, it's worth noting that JavaScript has many advanced features, such as async/await, promise chaining, and functional programming concepts, which might be relevant to more complex benchmarks.

**Alternatives**

If you're looking for alternatives to MeasureThat.net, consider the following options:

1. **Benchmarking libraries:** There are several benchmarking libraries available for Node.js, including `benchmark` and `jsperf`.
2. **Test-driven development (TDD) frameworks:** Frameworks like Mocha and Jest provide built-in support for running benchmarks and tests.
3. **Web performance testing tools:** Tools like WebPageTest and Lighthouse offer advanced features for measuring web application performance.

Keep in mind that each of these alternatives has its own strengths, weaknesses, and use cases. MeasureThat.net is specifically designed for JavaScript microbenchmarks, so it's an excellent choice for comparing the performance of small snippets of code.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36 Edg/114.0.1823.43

Browser/OS: Chrome 114 on Windows

View result in a separate tab

Test name	Executions per second
not obj	9072898.0 Ops/sec
obj is null or obj is undefined	2963607.2 Ops/sec
type of obj is undefined or obj is null	8623800.0 Ops/sec

Related benchmarks:

check if obj is null or undefined (version: 1)

Comparing performance of: not obj vs obj is null or obj is undefined vs type of obj is undefined or obj is null

Created: one year ago by: Registered User

Jump to the latest result

not obj

obj is null or obj is undefined

type of obj is undefined or obj is null

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):