Benchmark: JS: Null vs Undefined

Tests:

null === null
null === null
typeof undefined === "undefined"
typeof undefined === "undefined"

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
null === null
typeof undefined === "undefined"

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 break down what's being tested in this JavaScript microbenchmark.

**Benchmark Purpose**

The goal of this benchmark is to compare the performance of two seemingly equivalent expressions: `null === null` and `typeof undefined === "undefined"`. The benchmark measures which approach is faster, as it can impact the performance of certain parts of the codebase.

**Options Compared**

There are only two options being compared:

1. **Null Coalescing Operator (`??`)**: Not explicitly mentioned in this benchmark, but implied by the presence of `typeof undefined === "undefined"`.
2. **Equality Check (`===`)**: Using `null === null`.

**Pros and Cons**

### Equality Check (`===`)

Pros:

* Simple and widely supported.
* Intuitive to understand.

Cons:

* May involve a more expensive operation, such as dereferencing the `null` object, which can lead to performance issues in certain situations.

### Null Coalescing Operator (`??`)

Pros:

* Can be a more efficient way to perform comparisons, especially when working with `undefined` or `null`.
* Supports chaining, making it easier to write more expressive code.

Cons:

* Less intuitive for beginners, as the syntax is not immediately clear.
* Not all browsers support this operator (only from ECMAScript 2020+).

**Special Consideration**

The benchmark uses a special JavaScript feature: the `typeof` operator with a string literal `"undefined"`. This allows testing whether the `typeof` operator is able to provide the correct result for this specific case. If the result was incorrect, it could indicate a bug or misbehavior in the JavaScript engine.

**Other Alternatives**

Other alternatives to compare performance could include:

1. **Using `null` with a primitive value**: Compare performance of `null === 0`, `null === true`, etc.
2. **Comparing against an array**: Compare performance of `[] === []`, `[].push(0) === [], [] === []`, etc.
3. **Comparing with different data types**: Compare performance of `null === undefined`, `null === null` (the current benchmark), or other combinations.

Keep in mind that each alternative will test a specific aspect of JavaScript's behavior and might not be directly comparable to the current benchmark.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36

Browser/OS: Chrome 106 on Windows

View result in a separate tab

Test name	Executions per second
null === null	1235995008.0 Ops/sec
typeof undefined === "undefined"	11492810.0 Ops/sec

Related benchmarks:

JS: Null vs Undefined (version: 0)

Comparing performance of: null === null vs typeof undefined === "undefined"

Created: 2 years ago by: Guest

Jump to the latest result

null === null

typeof undefined === "undefined"

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):