Benchmark: undefined vs null vs bool vs isInteger check

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };

Tests:

undefined
undefined !== obj.d;
typeof
null !== obj.d;
bool
!! obj.d;
IsInteger
Number.isInteger(obj.d);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
undefined
typeof
bool
IsInteger

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 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
undefined	663471488.0 Ops/sec
typeof	658224128.0 Ops/sec
bool	682934656.0 Ops/sec
IsInteger	695858688.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what is being tested, compared, and analyzed.

**Benchmark Overview**

The benchmark compares the performance of different ways to check if a value is not equal to `undefined` or `null`, and also checks if a value is an integer using a specific function (`Number.isInteger()`).

**Test Cases**

There are four test cases:

1. `undefined !== obj.d;`: This tests whether checking for `undefined` is faster than other methods.
2. `null !== obj.d;`: This tests whether checking for `null` is faster than other methods.
3. `!! obj.d;`: This uses a double-bang operator (`!!`) to check if the value is not equal to zero, effectively checking for non-zero values.
4. `Number.isInteger(obj.d);`: This uses a built-in function (`Number.isInteger()`) to check if the value is an integer.

**Library and Special JS Features**

* In test case 3, the double-bang operator (`!!`) is used. This is a syntax feature in JavaScript that converts its operand to a boolean value.
* In test case 4, the `Number.isInteger()` function is used, which is a built-in function in modern JavaScript versions.

**Comparison of Approaches**

Here's a brief overview of each approach and their pros and cons:

1. `undefined !== obj.d;`:
	* Pros: Simple and straightforward.
	* Cons: May not be as efficient as other methods due to the comparison operator's overhead.
2. `null !== obj.d;`:
	* Pros: Similar to the first method, but with a different value for the comparison operator.
	* Cons: Same cons as above.
3. `!! obj.d;` (double-bang operator):
	* Pros: Can be more efficient than using comparison operators, as it avoids creating temporary values.
	* Cons: May not work as expected if `obj.d` is a very large value, causing integer overflow.
4. `Number.isInteger(obj.d);`:
	* Pros: Highly optimized and implemented in native code for performance.
	* Cons: Not supported in older JavaScript versions.

**Other Considerations**

* The benchmark uses a specific test object (`obj`) with known values to ensure consistent results.
* The test cases are designed to highlight the differences in performance between these approaches, rather than providing an exhaustive comparison of all possible methods.

**Alternatives and Future Directions**

If you were to implement this benchmark yourself, you might consider using other libraries or functions to perform similar checks. Some alternatives could be:

* `typeof` with a specific type (e.g., `'number'`)
* Using the `===` operator instead of `!==`
* Implementing custom functions for checking integer values

However, since these benchmarks are designed to measure performance and the specific test cases used here are likely optimized for speed, it's essential to use the most efficient methods available in your target JavaScript environment.

Related benchmarks:

undefined vs null vs bool vs isInteger check (version: 0)

type check performance

Comparing performance of: undefined vs typeof vs bool vs IsInteger

Created: 3 years ago by: Registered User

Jump to the latest result

undefined

typeof

bool

IsInteger

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):