Benchmark: typof vs null - MeasureThat.net

Script Preparation code:

obj = {"kl":"jl"};

Tests:

typoef
if(typeof obj["kl"] === "undefined") var n = 2;
null
if(obj["kl"]) var n = 3;
typof neg
if(typeof obj["ka"] === "undefined") var n = 2;
null neg
if(obj["ka"]) var n = 3;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typoef
null
typof neg
null neg

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided JSON represents a JavaScript microbenchmark that tests the performance of different approaches to check for null or undefined values in an object.

**Script Preparation Code**

The script preparation code `obj = {\"kl\":\"jl\"};` creates an object `obj` with a property named "kl" set to the string "jl".

**Html Preparation Code**

There is no HTML preparation code provided, which means that this benchmark does not test any specific JavaScript feature or syntax related to DOM manipulation.

**Individual Test Cases**

The benchmark consists of four individual test cases:

1. `typoef`: Tests whether checking for a non-existent property using `typeof obj["kl"] === "undefined"` is slower than checking directly for the null value `obj["kl"] == null`.
2. `null`: Tests whether checking for an existing property using `obj["kl"]` is faster or equally fast as the above test case.
3. `typof neg`: Similar to `typoef`, but with a negative check for non-existence (`typeof obj["ka"] === "undefined"`).
4. `null neg`: Similar to `null`, but with a negative check for existence (`obj["ka"] == null`).

**Comparison of Options**

The benchmark compares two approaches:

1. **Direct property access**: Checking directly for the value using `obj["kl"]`.
2. **Using typeof and === operators**: Checking for non-existence or equality using `typeof obj["kl"] === "undefined"`.

Pros and Cons:

* Direct property access is generally faster because it avoids the overhead of type checking.
	+ Pros: More efficient, less CPU usage.
	+ Cons: May lead to runtime errors if the property doesn't exist.
* Using typeof and === operators checks for non-existence or equality in a more explicit way.
	+ Pros: Reduces runtime errors, provides better feedback on why a test failed.
	+ Cons: Slower due to type checking overhead.

**Other Considerations**

The benchmark also considers the impact of using `== null` instead of just `==`. This check is only necessary if you're checking for `null` explicitly. In modern JavaScript, you can simply use `===` for equality checks.

**Libraries and Special Features**

There are no specific libraries used in this benchmark. The tests rely on built-in JavaScript features, specifically the `typeof` operator and property access syntax.

**Special JS Features or Syntax**

The benchmark uses some special syntax:

* Property access using square brackets (`obj["kl"]`)
* Type checking with `typeof` and `===`

If you're interested in learning more about these topics, here are some resources:

* [Property Access](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_access)
* [Type Checking](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/typeof)

**Alternatives**

If you're interested in exploring other microbenchmarking tools or approaches, here are some alternatives:

1. **Benchmark.js**: A popular JavaScript benchmarking library that provides more advanced features and flexibility.
2. **js-benchmark**: Another lightweight JavaScript benchmarking library that offers a simple API for creating benchmarks.
3. **Google's Benchmark**: A high-performance benchmarking library developed by Google engineers, which is designed to be fast and efficient.

I hope this explanation helps! Let me know if you have any further questions or need clarification on any of the points.

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:53.0) Gecko/20100101 Firefox/53.0

Browser/OS: Firefox 53 on Windows

View result in a separate tab

Test name	Executions per second
typoef	362373248.0 Ops/sec
null	361581120.0 Ops/sec
typof neg	359357024.0 Ops/sec
null neg	364439776.0 Ops/sec

Related benchmarks:

typof vs null (version: 0)

Comparing performance of: typoef vs null vs typof neg vs null neg

Created: 7 years ago by: Registered User

Jump to the latest result

typoef

null

typof neg

null neg

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):