Benchmark: undefined check tests

Tests:

typeof
var name; typeof(name) === 'undefined'
IIFE
var name; name === (function(window, undefined){ // undefined }(this))
void
var name; name === void(0)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
IIFE
void

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/85.0.4183.121 Safari/537.36

Browser/OS: Chrome 85 on Windows

View result in a separate tab

Test name	Executions per second
typeof	720089408.0 Ops/sec
IIFE	718474752.0 Ops/sec
void	710439424.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**

The benchmark definition is a JSON object that represents a specific JavaScript microbenchmark. In this case, there are three benchmarks defined:

1. "undefined check tests"
2. "var name; typeof(name) === 'undefined'"
3. "var name; name === void(0)"

These benchmarks test different ways to check if a variable is undefined.

**Options Compared**

The options being compared in these benchmarks are:

* Checking for `undefined` using the `typeof` operator (Benchmark 1)
* Checking for `undefined` by invoking a function that returns `undefined` (Benchmark 2, which uses an IIFE - Immediately Invoked Function Expression)
* Using the `void` function to create an expression that evaluates to `undefined` (Benchmark 3)

**Pros and Cons of Each Approach**

Here are some pros and cons for each approach:

1. **Checking for `undefined` using `typeof` operator**:
	* Pros: Simple, widely supported, and efficient.
	* Cons: Can be slower than other approaches because it involves a function call.
2. **Checking for `undefined` by invoking an IIFE**:
	* Pros: Can be faster than the first approach because it avoids the overhead of a function call.
	* Cons: Requires careful implementation to ensure the IIFE is called correctly, and may not work in all situations (e.g., when `this` is `null`).
3. **Using the `void` function**:
	* Pros: Simple, efficient, and widely supported.
	* Cons: May be slower than the first approach due to its additional overhead.

**Libraries Used**

There are no libraries explicitly mentioned in the benchmark definition or test cases. However, it's likely that the benchmark is written using a library like Benchmark.js, which provides a simple way to create microbenchmarks.

**Special JS Features/Syntax**

There is one special feature used in Benchmark 2: Immediately Invoked Function Expression (IIFE). An IIFE is a function that is called immediately after its definition. In this case, the IIFE returns `undefined`, which is then compared to the variable `name`.

Other than that, there are no other special features or syntax mentioned in the benchmark definition or test cases.

**Alternatives**

If you want to create microbenchmarks like this one, you can use a library like Benchmark.js. Some alternative approaches to creating microbenchmarks include:

* Using a framework like Webpack's `benchmark` module
* Creating your own custom benchmarking utility using JavaScript
* Using a library like Microbenchmark (which is a popular alternative to Benchmark.js)

Note that the choice of approach will depend on your specific needs and preferences.

Related benchmarks:

undefined check tests (version: 0)

Comparing performance of: typeof vs IIFE vs void

Created: 4 years ago by: Guest

Jump to the latest result

typeof

IIFE

void

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):