Benchmark: Testing for false vs undefined vs == null vs hasOwnProperty vs hasOwn for undefined member

Testing for false vs undefined vs == null vs hasOwnProperty vs hasOwn for undefined member (version: 1)

Is there a performance benefit to replacing == null with a logical test?

Comparing performance of: test false vs test undefined vs test hasOwnProperty vs test == null vs test == undefined vs test static hasOwnProperty vs test static hasOwn

Created: 4 years ago by: Registered User

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Tests:

test false
var n = {}; while(true) { if(!n.foo) break; }
test undefined
var n = {}; while(true) { if(n.foo===undefined) break; }
test hasOwnProperty
var n = {}; while(true) { if(!n.hasOwnProperty('foo')) break; }
test == null
var n = {}; while(true) { if(n.foo==null) break; }
test == undefined
var n = {}; while(true) { if(n.foo==undefined) break; }
test static hasOwnProperty
var n = {}; while(true) { if(!Object.hasOwnProperty(n,'foo')) break; }
test static hasOwn
var n = {}; while(true) { if(!Object.hasOwn(n, 'foo')) break; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
test false
test undefined
test hasOwnProperty
test == null
test == undefined
test static hasOwnProperty
test static hasOwn

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Linux

View result in a separate tab

Test name	Executions per second
test false	127937272.0 Ops/sec
test undefined	15704152.0 Ops/sec
test hasOwnProperty	95204312.0 Ops/sec
test == null	185662608.0 Ops/sec
test == undefined	15813345.0 Ops/sec
test static hasOwnProperty	7224817.0 Ops/sec
test static hasOwn	14250494.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring the performance of different approaches to check for the absence or nullity of properties in JavaScript objects is crucial, especially when it comes to optimizing code.

**Benchmark Definition**

The benchmark measures the execution speed of six different methods:

1. `!n.foo` (using the logical NOT operator)
2. `n.foo===undefined`
3. `!n.hasOwnProperty('foo')` (using the `hasOwnProperty` method on the object itself)
4. `n.foo==null`
5. `n.foo==undefined`

**Options Compared**

The benchmark compares these six methods to determine which one is the fastest, most efficient, and reliable.

**Pros and Cons of Each Approach:**

1. `!n.foo`: This approach uses the logical NOT operator to check if a property exists or not. It's concise and easy to read.
	* Pros: Fast, simple, and intuitive.
	* Cons: Some older browsers may not support the logical NOT operator, and it may not work as expected with certain data types (e.g., NaN).
2. `n.foo===undefined`: This approach uses a strict equality check to verify if a property has no value.
	* Pros: Widely supported across modern browsers, reliable for all data types.
	* Cons: Less concise than the first option, may be slower due to the additional operation.
3. `!n.hasOwnProperty('foo')`: This approach checks if an object has a specific property using the `hasOwnProperty` method on itself.
	* Pros: Works with both objects and arrays, reliable for all data types.
	* Cons: Less concise than the first option, may be slower due to the additional operation.
4. `n.foo==null`: This approach uses a loose equality check to verify if a property has no value (i.e., null or undefined).
	* Pros: Widely supported across modern browsers, reliable for some data types (e.g., null).
	* Cons: Less reliable than other options, may not work as expected with certain data types (e.g., NaN).
5. `n.foo==undefined`: This approach uses a loose equality check to verify if a property has no value.
	* Pros: Widely supported across modern browsers, reliable for some data types (e.g., null).
	* Cons: Less concise than other options, may not work as expected with certain data types (e.g., NaN).

**Library Usage**

None of the test cases use external libraries.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax used in this benchmark. All options rely on standard JavaScript constructs.

**Other Alternatives**

Some alternative approaches to check for property absence could include:

* Using `in` operator with a null value: `!n['foo'] in n`
* Using a function to check if a property exists
* Using a regex pattern to match the absence of a property

However, these alternatives are not part of this specific benchmark and may have different performance characteristics or trade-offs.

Overall, the benchmark provides valuable insights into the relative performance of different approaches to checking for property absence in JavaScript objects.

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