Benchmark: undefined vs. typeof vs. in vs. hasOwnProperty

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };

obj.check = function(name) { return !!this[name]; };

Tests:

hasOwnProperty
obj.hasOwnProperty( 'd' );
bool with Array
!! obj['d'];
bool
!! obj.d;
With methode
obj.check('d');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
hasOwnProperty
bool with Array
bool
With methode

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**Benchmark Overview**

The provided JSON represents a benchmark test case that compares the performance of four different approaches to check if a property exists in an object: `hasOwnProperty`, boolean with array syntax (`!! obj['d'];`), boolean without array syntax (`!! obj.d;`), and calling a custom method (`obj.check('d');`).

**Approaches Compared**

1. **`hasOwnProperty`**: This approach checks if the property is present in the object using the `hasOwnProperty()` method.
2. **Boolean with Array Syntax**: This approach uses the double-asterisk operator (`!!`) to check if a property exists in an array.
3. **Boolean without Array Syntax**: This approach uses a simple boolean expression (`!! obj.d;`) to check if a property exists in an object.
4. **With Method**: This approach defines a custom method `check` on the object and calls it with the property name as an argument.

**Pros and Cons of Each Approach**

1. **`hasOwnProperty`**:
	* Pros: Reliable, widely supported, and easy to read.
	* Cons: Can be slower due to the additional method call.
2. **Boolean with Array Syntax** (`!! obj['d'];`):
	* Pros: Fast and concise.
	* Cons: Not applicable for objects; only works with arrays.
3. **Boolean without Array Syntax** (`!! obj.d;`):
	* Pros: Fast and easy to read.
	* Cons: May not work in older browsers or environments that don't support object property access via bracket notation.
4. **With Method** (`obj.check('d');`):
	* Pros: Customizable, can be more readable for complex logic.
	* Cons: Adds extra overhead due to method call and may not be as performant.

**Library Usage**

None of the benchmark test cases use a specific JavaScript library.

**Special JS Features or Syntax**

There is no special JS feature or syntax used in these benchmark test cases. The only thing unique about `!! obj['d'];` is that it's using a non-standard operator (`!!`) which is not supported by all browsers.

**Other Alternatives**

If you need to optimize object property lookup performance, consider the following alternatives:

1. **Using `in`**: Instead of `hasOwnProperty`, use the `in` operator to check if a property exists in an object: `!! obj['d'] === true`.
2. **Using a custom method with caching**: Implement a custom method that caches results for frequently accessed properties, which can improve performance.
3. **Avoiding unnecessary property accesses**: Optimize code by avoiding unnecessary property accesses or using lazy loading techniques.

By understanding these alternatives and trade-offs, you can make informed decisions when optimizing object property lookup performance in your JavaScript applications.

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0

Browser/OS: Firefox 56 on Windows

View result in a separate tab

Test name	Executions per second
hasOwnProperty	208678720.0 Ops/sec
bool with Array	517099552.0 Ops/sec
bool	517026496.0 Ops/sec
With methode	242204192.0 Ops/sec

Related benchmarks:

undefined vs. typeof vs. in vs. hasOwnProperty (version: 0)

Object lookup performance

Comparing performance of: hasOwnProperty vs bool with Array vs bool vs With methode

Created: 7 years ago by: Guest

Jump to the latest result

hasOwnProperty

bool with Array

bool

With methode

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):