Benchmark: null vs undefined reversed

Tests:

case for undefined
for (let i = 0; i < 1000; i++) { undefined; }
case for null
for (let i = 0; i < 1000; i++) { null; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
case for undefined
case for null

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36

Browser/OS: Chrome 95 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
case for undefined	7746.0 Ops/sec
case for null	3159845.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is an essential task, and MeasureThat.net provides a great platform to do so.

Let's dive into the provided benchmark and analyze what's being tested.

**Benchmark Definition JSON**

The provided JSON defines a single benchmark: "null vs undefined reversed". This means that the benchmark compares the performance of using `undefined` versus `null` in a loop. The word "reversed" suggests that the test is likely measuring which approach results in fewer function calls, as `undefined` might be optimized differently than `null`.

**Options Compared**

The two options being compared are:

1. **`undefined`**: In JavaScript, `undefined` is a primitive value that represents an uninitialized or unassigned variable. When used in a loop, the engine may optimize it to be a single value reference.
2. **`null`**: `null` is also a primitive value that represents the absence of any object value. When used in a loop, the engine treats it as a distinct entity from `undefined`.

**Pros and Cons**

* **`undefined`**:
	+ Pros: Might be optimized to a single value reference, potentially reducing function call overhead.
	+ Cons: Can lead to unexpected behavior if not handled properly (e.g., using `typeof undefined` or checking for `undefined` explicitly).
* **`null`**:
	+ Pros: More explicit and safer than using `undefined`, as it's more intuitive to work with a null value than an uninitialized variable.
	+ Cons: Might incur additional overhead due to the single-value reference optimization.

**Library Usage**

There is no library usage mentioned in the provided JSON. However, it's worth noting that MeasureThat.net often uses libraries like V8.js (the JavaScript engine used by Google Chrome) or SpiderMonkey (the JavaScript engine used by Mozilla Firefox) for benchmarking.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark. The focus is on the basic distinction between `undefined` and `null`.

**Other Alternatives**

If you were to create a similar benchmark, you could consider testing other options, such as:

* Using an uninitialized variable (`var x = ;`)
* Using a reference to a non-existent object (`let obj = { foo: 42 };`)
* Comparing the performance of using `undefined` versus `null` in different contexts (e.g., within an array or as a function parameter)

Keep in mind that MeasureThat.net provides a wide range of benchmarks, so you can explore other options by browsing their website.

If you have any further questions or need more information on specific JavaScript topics, feel free to ask!

Related benchmarks:

null vs undefined reversed (version: 0)

reverse of https://www.measurethat.net/Benchmarks/Show/15627

Comparing performance of: case for undefined vs case for null

Created: 3 years ago by: Guest

Jump to the latest result

case for undefined

case for null

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):