Toggle navigation
MeasureThat
.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
JS instanceof vs in
(version: 0)
Comparing performance of:
instanceof vs in
Created:
3 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var obj = {a:2};
Tests:
instanceof
obj instanceof Object
in
'a' in obj
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
instanceof
in
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
8 months ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0
Browser/OS:
Firefox 146 on Windows
View result in a separate tab
Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=622308" width="100%" height="500px"></iframe>
in
3855.1M/s
instanceof
345.9M/s
View exact numbers
Test name
Executions per second
✓
in
3,855,095,808 Ops/sec
instanceof
345,943,008 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what's being tested, compared, and considered. **Benchmark Overview** The MeasureThat.net website is used to compare the performance of two approaches: `instanceof` and the `in` operator in JavaScript. The benchmark involves creating an object with a single property (`obj = {a:2};`) and then testing both methods on this object. **What's Being Tested?** Two individual test cases are being compared: 1. `instanceof`: This method checks if an object is an instance of a particular constructor function. In this case, it's checking if the object `obj` is an instance of the `Object` constructor. 2. `in`: This operator checks if a property exists in an object. Here, it's checking if the key `'a'` is present in the object `obj`. **Options Compared** The two options being compared are: * `instanceof` * `in` **Pros and Cons of Each Approach:** 1. **`instanceof`:** * Pros: + Provides more information about the type of object (its constructor function). + Can be useful in certain scenarios, such as checking if an object is a specific type. * Cons: + May be slower than the `in` operator due to the overhead of creating a new object and calling its constructor. 2. **`in`:** * Pros: + Generally faster than `instanceof`. * Cons: + Only checks if a property exists, without providing information about the type of object. **Library and Special JS Features** There is no library being used in this benchmark, but it does utilize the built-in JavaScript operators: * `in`: This operator is part of the ECMAScript standard. * `instanceof`: This method is also part of the ECMAScript standard. **Other Considerations** When working with objects and properties, it's essential to consider the following factors: * **Cache locality**: Some browsers might optimize certain operations by caching results or reusing existing computations. MeasureThat.net might be exploiting this behavior. * **Browser-specific optimizations**: Different browsers may implement their own optimizations for these operators, which could affect performance. **Alternatives** For those interested in exploring alternative approaches, consider the following: 1. **Using `hasOwnProperty()`**: Instead of using the `in` operator, you can use the `hasOwnProperty()` method to check if an object has a specific property. ```javascript if (obj.hasOwnProperty('a')) { // ... } ``` 2. **Using `Object.prototype.hasOwnProperty()`:** If you're working with objects that don't have their own `hasOwnProperty()` method, you can use the inherited `hasOwnProperty()` method from `Object.prototype`. ```javascript if (Object.prototype.hasOwnProperty.call(obj, 'a')) { // ... } ``` Keep in mind that using `Object.prototype.hasOwnProperty()` may introduce additional overhead due to the need to access the prototype chain. I hope this explanation helps software engineers understand what's being tested and compared on MeasureThat.net!
Related benchmarks
instanceof vs in
instanceof vs typeof gyuguyguy
instanceof vs typeof franco
Comments
Confirm delete:
Do you really want to delete benchmark?