Toggle navigation
MeasureThat.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
non null vs. typeof vs. in vs. Object.hasOwnProperty
(version: 0)
Object lookup performance
Comparing performance of:
undefined vs typeof vs in vs hasOwnProperty
Created:
6 years ago
by:
Registered User
Jump to the latest result
Script Preparation code:
var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };
Tests:
undefined
null != obj.d; null != obj.f;
typeof
'undefined' !== typeof obj.d; 'undefined' !== typeof obj.f;
in
'd' in obj; 'f' in obj;
hasOwnProperty
obj.hasOwnProperty( 'd' ); obj.hasOwnProperty( 'f' );
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (4)
Previous results
Fork
Test case name
Result
undefined
typeof
in
hasOwnProperty
Fastest:
N/A
Slowest:
N/A
Latest run results:
No previous run results
This benchmark does not have any results yet. Be the first one
to run it!
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the explanation of the provided benchmark. **Overview** The benchmark measures the performance of different approaches for object lookup in JavaScript. Specifically, it compares the following methods: 1. `null != obj.d` (using the "not equal" operator) 2. `'undefined' !== typeof obj.d` (using a type comparison) 3. `'d' in obj` (using the "in" operator) 4. `obj.hasOwnProperty('d')` (using the `hasOwnProperty` method) **Null != obj.d** This test checks for non-null values in an object. The `null !=` operator returns true if the value is not null, and false otherwise. Pros: * Simple and straightforward * Fast performance Cons: * Not all browsers support this syntax (Chrome 95 does, but some other browsers might not) * May be less readable for developers familiar with more explicit comparisons **'undefined' !== typeof obj.d** This test uses a type comparison to check if the value is `undefined`. The `'undefined' !== typeof` expression checks if the value of `obj.d` (or any other property) is not equal to the result of calling `typeof` on it. If `typeof` returns `"object"`, then the value is an object, which might be a different behavior than expected. Pros: * More explicit and readable for developers familiar with type comparisons * Works in all browsers Cons: * May be slower performance compared to direct comparison (`null !=`) * Requires more complex syntax **'d' in obj** This test uses the "in" operator to check if a property exists in an object. The `'d' in obj` expression checks if `obj` has a property named `"d"`. Pros: * Fast performance * Works well for checking property existence Cons: * May be less readable for developers familiar with direct comparison operators * Requires support for the "in" operator, which some older browsers might not have **obj.hasOwnProperty('d')** This test uses the `hasOwnProperty` method to check if an object has a property named `"d"`. The `obj.hasOwnProperty('d')` expression checks if `obj` has a property named `"d"` and is owned by itself (i.e., not inherited from its prototype). Pros: * Fast performance * Works well for checking property existence in objects Cons: * May be less readable for developers familiar with direct comparison operators or "in" operator * Requires support for the `hasOwnProperty` method, which some older browsers might not have **Library and Syntax** None of these tests use a specific JavaScript library. They rely on built-in JavaScript features. **Special JS Feature/Syntax** The test case uses the following special syntax: * `'d' in obj`: This is a valid syntax for using the "in" operator to check if a property exists in an object. * `obj.hasOwnProperty('d')`: This is a method call, not just a property access. These tests do not use any other special JavaScript features or syntax beyond what's described above. **Other Alternatives** Some alternative approaches for object lookup might include: * Using the `in` operator with the `Object.keys()` method to get an array of all property names in an object. * Using the `hasOwnProperty` method with a loop to check if an object has a certain property. * Using a custom implementation using bitwise operations (e.g., checking for bit patterns) or hash tables.
Related benchmarks:
undefined vs. typeof vs. in vs. hasOwnProperty
undefined vs. typeof vs. in vs. hasOwnProperty 2
undefined vs. typeof vs. in vs. hasOwnProperty big object
hasOwnProperty string vs number
in vs hasOwn
Comments
Confirm delete:
Do you really want to delete benchmark?