Toggle navigation
MeasureThat
.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
instanceof vs undefined prop
(version: 0)
Comparing performance of:
instanceof vs checking prop
Created:
5 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var obj = {a:2};
Tests:
instanceof
obj instanceof Object
checking prop
obj.a === true
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
instanceof
checking prop
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) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36
Browser/OS:
Chrome 137 on Windows
View result in a separate tab
Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=609193" width="100%" height="500px"></iframe>
instanceof
92.4M/s
checking prop
91.7M/s
View exact numbers
Test name
Executions per second
✓
instanceof
92,448,728 Ops/sec
checking prop
91,692,416 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to help you understand the provided benchmark! **What is being tested?** The test cases measure the performance of two different approaches: 1. **`obj instanceof Object`**: This checks if an object `obj` has a prototype that is an instance of the `Object` class. 2. **`obj.a === true`**: This checks if the value of property `a` in the object `obj` is equal to `true`. **What are the pros and cons of each approach?** 1. **`obj instanceof Object`**: * Pros: This approach checks for a specific prototype chain, which can be efficient for verifying that an object has a certain structure. * Cons: It may not be as straightforward or readable as other approaches, and it requires knowledge of JavaScript's prototype system. 2. **`obj.a === true`**: * Pros: This approach is simple and easy to read, but it relies on the specific value `true` being stored in property `a`. If this value changes, the test may fail unexpectedly. * Cons: It can be slower or more memory-intensive if the object `obj` has a large number of properties or if property `a` is accessed frequently. **Other considerations** * Both approaches assume that property `a` exists on object `obj`. If this property does not exist, the tests may fail unexpectedly. * The tests do not account for the fact that `obj.a === true` will return `true` even if `a` is a number (e.g., 1) or another value that equals `true`. **Library and special JS features** There are no libraries used in this benchmark, but it does rely on JavaScript's built-in `Object` class. **Special JS feature** The test case uses the syntax `obj instanceof Object`, which relies on JavaScript's prototype system. This is a standard feature of JavaScript that allows you to check if an object has a certain prototype chain. **Other alternatives** Some alternative approaches to verify the existence or value of property `a` in object `obj` might include: * Using a simple equality check like `obj.a === obj.a || (typeof obj.a !== 'undefined' && obj.a)`: This approach is more robust than just checking for `true`, but it may still be slower or less memory-efficient. * Using a dedicated library like Lodash's `has` function: This approach can provide more flexibility and robustness, but it adds an additional dependency to the benchmark. I hope this explanation helps! Let me know if you have any further questions.
Related benchmarks
instanceof vs typeof vs prop check
JS instanceof vs in
instanceof vs typeof franco
Comments
Confirm delete:
Do you really want to delete benchmark?