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instanceof vs in
(version: 0)
Comparing performance of:
instanceof test vs in test
Created:
2 years ago
by:
Guest
Go to the latest result
Script Preparation code:
class ClassFoo { constructor() { this.bar = 1; } } var Foo = ClassFoo; var foo = new Foo();
Tests:
instanceof test
foo instanceof Foo
in test
'bar' in foo
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
instanceof test
in test
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
9 months ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:144.0) Gecko/20100101 Firefox/144.0
Browser/OS:
Firefox 144 on Windows
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<iframe src="https://measurethat.net/Embed?id=619097" width="100%" height="500px"></iframe>
in test
3898.1M/s
instanceof test
352.5M/s
View exact numbers
Test name
Executions per second
✓
in test
3,898,128,896 Ops/sec
instanceof test
352,450,752 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON benchmark definition and explanation what is being tested. **Benchmark Definition** The benchmark consists of two test cases: 1. `foo instanceof Foo` 2. `'bar' in foo` **What is being tested?** These two test cases are comparing the performance of the JavaScript operators `instanceof` and `in`. The `instanceof` operator checks if an object is an instance of a specific constructor, whereas the `in` operator checks if a property (in this case, `bar`) is present in an object. **Options compared** The two options being compared are: 1. `foo instanceof Foo`: This uses the `instanceof` operator to check if `foo` is an instance of the `Foo` class. 2. `'bar' in foo`: This uses the `in` operator to check if `bar` is a property present in the `foo` object. **Pros and Cons** * **instanceof**: This method can be more accurate for checking if an object is an instance of a specific class, as it takes into account the constructor's prototype chain. However, it may also lead to slower performance due to its use of dynamic typing. * **in**: This method is generally faster than `instanceof` because it uses a simpler property lookup operation. However, it can return false positives if the object has inherited properties from other classes. **Other considerations** In this specific benchmark, the `foo instanceof Foo` test case may be affected by the fact that `Foo` is defined using the `class` keyword, which creates a new scope for the constructor. This could lead to a slight overhead in terms of performance. **Library and special features** There is no library being used in this benchmark. However, it does utilize some JavaScript features: * **`class` keyword**: This feature allows defining classes with constructors. * **Arrow functions**: Although not explicitly shown, arrow functions are implied by the use of `var foo = new Foo();`. **Alternatives** If you wanted to write a similar benchmark for these two operators, you could consider using other languages or frameworks that also support operator overloading, such as: * Python: Using `isinstance()` and `in` * Java: Using `instanceof` and `containsKey()` * C++: Using `dynamic_cast` and `std::map::find` However, keep in mind that each language has its own strengths and weaknesses when it comes to performance, and the results may vary depending on the specific implementation and hardware.
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