Benchmark: if(typeof <var> ===undefined) vs if(<var>)

Script Preparation code:

var a=undefined

Tests:

no typeof
var a=undefined if (a===undefined) true
typeof
var a=undefined if(typeof a===undefined) true

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
no typeof
typeof

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36

Browser/OS: Chrome 98 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
no typeof	4075052.0 Ops/sec
typeof	4090659.8 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the JavaScript benchmark being tested on MeasureThat.net.

**Benchmark Definition**

The benchmark definition consists of two JavaScript expressions that compare the behavior of `if(typeof <var> === undefined)` and `if(<var>)` when `<var>` is assigned a value of `undefined`.

**Options Compared**

There are two options compared:

1. **`typeof`**: This option checks if the variable `<var>` is of type `undefined`.
2. **No `typeof`**: In this case, it simply checks if `<var>` is equal to `undefined`, without using the `typeof` keyword.

**Pros and Cons**

Here's a brief analysis of each approach:

* **`typeof`**:
	+ Pros: More accurate when checking for `undefined` type, as `typeof undefined` returns `"undefined"`.
	+ Cons: May be slower due to the extra operation required.
* **No `typeof`**: Faster and more efficient, but may lead to incorrect results if `<var>` is not `undefined`.
* Additional consideration: When `<var>` has a value other than `undefined`, `if(typeof <var> === undefined)` will evaluate to `false`, while `if(<var>)` will be `true`. This is because `typeof` returns the type of the variable as a string, whereas `<var>` is simply its value.

**Library and Special JS Feature**

There is no specific library being used in this benchmark. However, it's worth noting that MeasureThat.net uses a custom JavaScript engine to execute the benchmarks.

**Test Cases**

The test cases are designed to compare the behavior of these two expressions under different conditions. The first test case checks the expression without using `typeof`, while the second test case explicitly uses `typeof`.

**Other Alternatives**

If you're looking for alternative benchmarking tools, here are a few options:

1. **Benchmark.js**: A popular benchmarking library that supports various benchmarks, including JavaScript.
2. **jsperf**: An old-school JavaScript benchmarking tool that allows you to write and compare performance tests.
3. **Google's Benchmark**: A high-performance benchmarking framework that supports C++ and other languages.

Keep in mind that MeasureThat.net is a specialized tool designed specifically for testing JavaScript benchmarks, so it may not be suitable for general-purpose benchmarking needs.

Related benchmarks:

if(typeof <var> ===undefined) vs if(<var>) (version: 0)

Comparing performance of: no typeof vs typeof

Created: 2 years ago by: Guest

Jump to the latest result

no typeof

typeof

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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