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typeof object vs obj.constructor
(version: 0)
Comparing performance of:
typeof vs constructor
Created:
4 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var obj = {};
Tests:
typeof
typeof obj === "object"
constructor
obj.constructor === Object
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
typeof
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):
I'll break down the benchmark definition and test cases for you. **Benchmark Definition** The benchmark is defined by a JSON object that specifies two script preparation codes, an HTML preparation code (which is null in this case), and a list of individual test cases. In essence, this benchmark measures the performance difference between two approaches: 1. **typeof operator**: This tests how fast the JavaScript engine can evaluate the `typeof` operator on an empty object (`obj = {};`) to determine its type. 2. **Object.constructor property**: This tests how fast the JavaScript engine can access and compare the value of the `constructor` property of an empty object (`obj = {};`) with the built-in `Object` constructor. **Options Compared** Two different approaches are compared: * Using the `typeof` operator to check if a variable is an object * Accessing the `constructor` property of an object and comparing it to the `Object` constructor **Pros and Cons of Each Approach** 1. **typeof operator**: This approach is more concise and directly checks if the variable is an object, making it potentially faster since it avoids unnecessary property access. * Pros: Concise, direct check, potentially faster * Cons: May not be as accurate or robust, as some browsers might return different values for `typeof` on certain types of objects 2. **Object.constructor property**: This approach provides more control and accuracy by directly comparing the constructor of an object to the built-in `Object` constructor. * Pros: More accurate, provides explicit control over comparison * Cons: Requires accessing the `constructor` property, which might be slower in some browsers **Library or Special JS Feature** There is no library or special JavaScript feature used in this benchmark. It only relies on standard JavaScript syntax and built-in properties. **Other Alternatives** If you wanted to compare these approaches, you could also consider using other methods: * Using a `instanceof` check instead of `typeof` * Using a custom function to check if an object is of a certain type * Using a library like `lodash.isObject()` or `Array.isArray()` Keep in mind that the performance difference between these approaches might be negligible in many cases, and other factors like browser version, engine implementation, and platform-specific optimizations might have a greater impact on performance.
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