Benchmark: if(!variable) vs if(variable===undefined) performance

Script Preparation code:

var variable;

Tests:

!variable
if(!variable);
variable===undefined
if(variable===undefined);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
!variable
variable===undefined

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (iPad; CPU OS 14_8 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/96.0.4664.53 Mobile/15E148 Safari/604.1

Browser/OS: Chrome Mobile iOS 96 on iOS 14.8

View result in a separate tab

Test name	Executions per second
!variable	14390653.0 Ops/sec
variable===undefined	5208312.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON to understand what's being tested and what options are being compared.

**Benchmark Definition**

The benchmark is testing two different ways to check if a variable is undefined or not. The first test checks if `!variable` (not operator) is true, while the second test checks if `variable === undefined` (strict equality). Both tests aim to measure which approach performs better in terms of performance.

**Options Compared**

Two options are being compared:

1. **`if(!variable)`**: This option uses the logical not operator (`!`) to check if the variable is falsey (i.e., null, 0, empty string, etc.). If `!variable` is true, it means the original variable is truthy.
2. **`if(variable === undefined)`**: This option checks for strict equality between the variable and `undefined`. If they are equal, it means the variable is indeed `undefined`.

**Pros and Cons**

Here's a brief rundown of each approach:

* **`if(!variable)`**:
	+ Pros: More concise and readable. It takes advantage of JavaScript's implicit coercion to convert variables to booleans.
	+ Cons: May not be as accurate in certain edge cases (e.g., when the variable is an object with `length === 0`, it would evaluate to falsey).
* **`if(variable === undefined)`**:
	+ Pros: More explicit and accurate. It clearly conveys the intention of checking for strict equality.
	+ Cons: Less concise and potentially more verbose.

**Library and Purpose**

There is no library mentioned in this benchmark definition. The tests rely on built-in JavaScript syntax.

**Special JS Feature or Syntax**

There are no special features or syntax used in this benchmarking test.

**Other Considerations**

When comparing the performance of these two approaches, consider factors like:

* Code readability and maintainability
* Performance overhead due to explicit checks vs implicit coercion
* Browser and platform compatibility

**Alternatives**

If you wanted to add more tests or alternatives to this benchmark, some options could be:

1. **Using `variable === null`**: This would test a different way to check for "undefined" variables.
2. **Testing with `let variable = 0;` or `let variable = '';`**: These would test the performance of checking for falsey values using implicit coercion vs explicit equality checks.
3. **Including more browsers and devices in the benchmark**: This would provide a broader view of how different platforms handle these tests.

Keep in mind that each addition should focus on clarifying specific aspects of JavaScript performance or syntax, rather than introducing new variables or edge cases without a clear goal.

Related benchmarks:

if(!variable) vs if(variable===undefined) performance (version: 0)

Comparing performance of: !variable vs variable===undefined

Created: 3 years ago by: Guest

Jump to the latest result

!variable

variable===undefined

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):