Benchmark: Test checking of literal object types - v2

Script Preparation code:

var cls = function() {},
    f = Object.getPrototypeOf,
	s = Object.prototype,
    constructorObject = function(a) {
        return (!!a) && (a.constructor === Object);
    },
    prototypeObject = function(a) {
        return f(a) === s;
    };

var obj = {};

Tests:

prototype
prototypeObject(obj); prototypeObject(new cls);
constructor
constructorObject(obj); constructorObject(new cls);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
prototype
constructor

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'll explain the test cases, options compared, and other considerations for the provided JavaScript microbenchmark.

**Benchmark Definition**

The benchmark measures the performance difference between checking if an object is a constructor (`constructorObject`) versus checking if an object's prototype is equal to the `Object.prototype` (`prototypeObject`). The benchmark creates two objects: `obj` (an empty object) and `cls` (a constructor function).

**Options Compared**

There are two options being compared:

1. **`prototypeObject(obj)`**: This option checks if the prototype of an object `obj` is equal to `Object.prototype`. It does this by using the `f` variable, which refers to `Object.getPrototypeOf`, and comparing it with `s`, which refers to `Object.prototype`.
2. **`constructorObject(obj)`**: This option checks if the constructor of an object `obj` is equal to `Object.constructor`. It returns a boolean value indicating whether the constructor matches.

**Pros and Cons**

* **`prototypeObject(obj)`**:
	+ Pros: This approach uses a direct comparison with `Object.prototype`, which might be faster since it doesn't involve a function call.
	+ Cons: If the object's prototype is not equal to `Object.prototype`, this test will still pass, even if the constructor is not a constructor (e.g., if the object has a custom prototype chain).
* **`constructorObject(obj)`**:
	+ Pros: This approach checks for a more specific condition (i.e., whether the constructor is an actual constructor). It's more robust than `prototypeObject` since it's less dependent on the order of inheritance.
	+ Cons: This test might be slower due to the function call and comparison operations involved.

**Other Considerations**

* The benchmark doesn't account for cases where the object has a custom prototype chain, which might affect the results.
* The use of `Object.getPrototypeOf` (which is available in modern browsers) ensures that the comparison is done correctly even if the object's prototype is not directly set to `Object.prototype`.
* The test creates two objects: `obj` and `cls`. This could potentially introduce overhead due to object creation, but it's likely negligible compared to the performance differences between the two options.

**Library/Functionality**

The `prototypeObject` function uses `Object.getPrototypeOf`, which is a part of the ECMAScript standard. `Object.prototype` is also a built-in constant in JavaScript.

**Special JS Feature/Syntax**

There are no special features or syntaxes used in this benchmark that would make it specific to certain browsers or environments.

**Alternatives**

Other alternatives for measuring object prototype checking performance might include:

* Using a library like `fast-prototypes` (which provides an optimized implementation of `Object.getPrototypeOf`)
* Creating a custom test function using `Set.prototype.size`, which can be used to measure the number of unique objects
* Using a benchmarking framework that supports JavaScript-specific optimization and caching mechanisms

Related benchmarks:

Test checking of literal object types - v2 (version: 0)

Comparing performance of: prototype vs constructor

Created: 3 years ago by: Guest

Jump to the latest result

prototype

constructor

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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