Benchmark: null vs. hasOwnProperty

Script Preparation code:

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

Tests:

exist null
obj.d != null;
exist hasOwnProperty
obj.hasOwnProperty( 'd' );
nonexist null
obj.f != null;
nonexist hasOwnProperty
obj.hasOwnProperty( 'f' );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
exist null
exist hasOwnProperty
nonexist null
nonexist hasOwnProperty

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:139.0) Gecko/20100101 Firefox/139.0

Browser/OS: Firefox 139 on Windows

View result in a separate tab

Test name	Executions per second
exist null	462952544.0 Ops/sec
exist hasOwnProperty	481050464.0 Ops/sec
nonexist null	474819392.0 Ops/sec
nonexist hasOwnProperty	478193760.0 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 provided benchmark definition and test cases to understand what is being tested.

**Benchmark Definition:**
The first part of the benchmark definition explains that it measures object lookup performance using the `null` vs. `hasOwnProperty` comparison.

**Script Preparation Code:**
The script preparation code creates an object `obj` with properties `a`, `b`, `c`, `d`, and `e`. This object will be used to test various lookups.

**Html Preparation Code:**
There is no HTML preparation code provided, which means the benchmark focuses solely on JavaScript performance.

**Individual Test Cases:**

1. `exist null`: Tests if a property exists in the object using the `!=` operator for a non-existent property (`obj.f`).
2. `exist hasOwnProperty`: Tests if a property exists in the object using the `hasOwnProperty()` method.
3. `nonexist null`: Tests if a property does not exist in the object using the `!=` operator for a non-existent property (`obj.f`).
4. `nonexist hasOwnProperty`: Tests if a property does not exist in the object using the `hasOwnProperty()` method.

**Comparison Options:**

There are two comparison options:

1. **Using `!=` (strict equality)**:
	* Pros: Simple, widely supported.
	* Cons: Can be slow due to type coercion and potential overhead of checking for existence.
2. **Using `hasOwnProperty()`**:
	* Pros: More efficient for existing properties, as it directly checks if the property exists in the object's prototype chain.
	* Cons: May not work correctly when used on non-object values (e.g., numbers or strings), and can be slower due to method lookup.

The benchmark compares these two approaches:

* `exist null` tests using `!=`, while `nonexist null` uses the same approach for a non-existent property.
* `exist hasOwnProperty` uses `hasOwnProperty()`, while `nonexist hasOwnProperty` uses the same approach for a non-existent property.

**Library:**
There is no explicit library mentioned in the benchmark definition. However, some of the test cases use the `hasOwnProperty()` method, which is a part of the JavaScript standard library.

**Special JS Feature or Syntax:**
None are explicitly mentioned in this benchmark.

**Other Considerations:**

* The benchmark uses a simple object with a limited number of properties to focus on performance. In real-world scenarios, objects can have many more properties and nested structures.
* The use of `!=` for property existence may not be the most idiomatic or efficient way to check if a property exists in modern JavaScript code.

**Alternatives:**
If you were to create a similar benchmark, you could consider:

1. Using `in` operator instead of `hasOwnProperty()`, as it is more efficient and widely supported.
2. Adding more test cases with varying object sizes, nested structures, or other properties that might impact performance.
3. Including tests for existing properties using different comparison operators (e.g., `===`, `!==`, `==`, `!=`) to ensure accurate results.

Keep in mind that the specific options and considerations may vary depending on your testing goals and requirements.

Related benchmarks:

null vs. hasOwnProperty (version: 0)

Object lookup performance

Comparing performance of: exist null vs exist hasOwnProperty vs nonexist null vs nonexist hasOwnProperty

Created: 5 years ago by: Guest

Jump to the latest result

exist null

exist hasOwnProperty

nonexist null

nonexist hasOwnProperty

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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