Benchmark: undefined equality vs negation

Script Preparation code:

var ops = [true, 1, false, 3, 4, 5, true, "foobar", {}, 3, 4, 5, 6, [], false, 2, true, 2, false, 212, true, 34, 1, 1.909090090909009090909090909, undefined];

Tests:

undefined equality
ops.filter(op => op === undefined);
check for undefined with negation
ops.filter(op => !op);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
undefined equality
check for undefined with negation

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
undefined equality	747421.6 Ops/sec
check for undefined with negation	14601142.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark test and explain what's being tested, compared, and considered.

**Benchmark Definition JSON**

The provided JSON represents a JavaScript microbenchmark, where users can create and run tests to compare the performance of different approaches. The benchmark definition includes:

* `Name`: A unique identifier for the benchmark.
* `Description`: An optional description of the benchmark (empty in this case).
* `Script Preparation Code`:
	+ This code is used to prepare the test script by defining an array of values (`ops`) that will be used in the benchmark. The array contains a mix of boolean, number, string, object, and undefined values.
* `Html Preparation Code`: An empty field, which suggests that no HTML preparation code is required for this benchmark.

**Individual Test Cases**

The benchmark consists of two test cases:

1. **Undefined Equality**: The script filter function is used to check if the `undefined` value exists in the array (`ops.filter(op => op === undefined)`).
2. **Check for Undefined with Negation**: The same filtering process is performed, but this time using negation (`!op`) to check for the absence of `undefined`.

**Options Compared**

The two test cases compare:

* The number of executions per second (in milliseconds) across different browsers and devices.

**Pros and Cons of Different Approaches**

1. **Undefined Equality**: This approach checks if the `undefined` value is directly equal to itself, which is a simple and straightforward operation.
	+ Pros: Easy to understand and implement.
	+ Cons: May not be optimized by the browser's engine due to its simplicity.
2. **Check for Undefined with Negation**: This approach uses negation to check if the value is not `undefined`. While this seems like a similar operation, it may trigger different optimization paths in the browser's engine.
	+ Pros: Can potentially benefit from better optimization or caching by the browser.
	+ Cons: May require additional overhead due to the use of negation.

**Library and Purpose**

None of the provided code uses any external libraries. The script preparation code defines an array of values (`ops`) that is used in both test cases.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax used in this benchmark.

**Other Alternatives**

If you were to write a similar benchmark, you might consider:

* Using more complex data structures (e.g., objects with nested properties) to simulate real-world scenarios.
* Incorporating other filtering methods (e.g., using `includes()` instead of `filter()`).
* Experimenting with different browsers and devices to identify performance differences.
* Adding more test cases to compare the performance of different approaches under various conditions.

Keep in mind that microbenchmarks are meant to be simple, yet representative of common use cases. The goal is to isolate specific performance characteristics and provide a baseline for comparison across different implementations.

Related benchmarks:

undefined equality vs negation (version: 0)

Comparing performance of: undefined equality vs check for undefined with negation

Created: one year ago by: Guest

Jump to the latest result

undefined equality

check for undefined with negation

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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