Benchmark: Compare null undefined speed

Script Preparation code:

var one = { a: 123, b: null }
var two = { a: 123, b: undefined }
var three = {a: 123}

Tests:

explicit null check
one.b == null
explicit null non-check
one.b != null
explicit undefined check
two.b == null
explicit undefined non-check
two.b != null
implicit undefined check
three.b == null
implicit undefined non-check
three.b != null

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
explicit null check
explicit null non-check
explicit undefined check
explicit undefined non-check
implicit undefined check
implicit undefined non-check

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.5 Safari/605.1.15

Browser/OS: Safari 17 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
explicit null check	8517670.0 Ops/sec
explicit null non-check	8507424.0 Ops/sec
explicit undefined check	8685057.0 Ops/sec
explicit undefined non-check	8519780.0 Ops/sec
implicit undefined check	8487093.0 Ops/sec
implicit undefined non-check	8399708.0 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 benchmark and its results.

**Benchmark Overview**

The benchmark measures the performance of JavaScript in comparing `null` and `undefined` values. The test case is set up by creating three objects, `one`, `two`, and `three`, each with a property `b`. Two of these properties are initialized to `null` or `undefined`, while the third is not.

**Options Compared**

There are four different approaches to compare `null` and `undefined` values:

1. **Explicit null check**: This involves using the `==` operator to explicitly compare `one.b` with `null`.
2. **Explicit undefined non-check**: This involves using the `!=` operator to explicitly exclude `null` from the comparison.
3. **Implicit undefined check**: This is an optimization that allows the browser to use a special case when comparing `undefined` values, as they cannot be compared directly to other values.
4. **Implicit undefined non-check**: This approach does not perform any optimization for `undefined` comparisons.

**Pros and Cons**

1. **Explicit null check**:
	* Pros: Clearly defined behavior, easy to understand, and maintain.
	* Cons: May introduce unnecessary overhead due to the explicit comparison.
2. **Explicit undefined non-check**:
	* Pros: Can provide a performance boost by avoiding unnecessary comparisons.
	* Cons: May lead to unexpected behavior if not properly understood.
3. **Implicit undefined check**:
	* Pros: Optimizes performance for `undefined` comparisons, reducing overhead.
	* Cons: May introduce subtle bugs or unexpected behavior if not carefully designed.
4. **Implicit undefined non-check**:
	* Pros: No optimization is applied, ensuring predictable behavior.
	* Cons: May result in reduced performance compared to the optimized approaches.

**Library Usage**

In this benchmark, no specific library is used that would impact the comparison logic directly. However, it's essential to note that some JavaScript engines or libraries might use optimizations or special cases for `undefined` comparisons.

**Special JS Features or Syntax**

There are no explicit references to special JavaScript features or syntax in this benchmark.

**Alternative Approaches**

Other alternatives to compare `null` and `undefined` values include:

* Using the `===` operator with a guard clause to check if `one.b` is not null before comparing it.
* Utilizing a library like Lodash, which provides utility functions for working with undefined values.
* Implementing custom comparison logic using bitwise operations or other techniques.

Keep in mind that these alternatives might introduce additional complexity and may not always provide better performance than the optimized approaches.

Related benchmarks:

Compare null undefined speed (version: 0)

Comparing performance of: explicit null check vs explicit null non-check vs explicit undefined check vs explicit undefined non-check vs implicit undefined check vs implicit undefined non-check

Created: 3 years ago by: Guest

Jump to the latest result

explicit null check

explicit null non-check

explicit undefined check

explicit undefined non-check

implicit undefined check

implicit undefined non-check

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):