Toggle navigation
MeasureThat.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
'value === undefined' VS 'typeof value === "undefined"' when value is defined
(version: 0)
Comparing performance of:
value === undefined vs typeof value === "undefined"
Created:
5 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var value = "hello";
Tests:
value === undefined
value === undefined
typeof value === "undefined"
typeof value === "undefined"
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
value === undefined
typeof value === "undefined"
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):
I'd be happy to explain what's being tested in the provided benchmark. **Benchmark Definition** The benchmark measures the performance difference between two JavaScript operators: `value === undefined` and `typeof value === "undefined"` when `value` is defined (i.e., not null or undefined). **Options Compared** Two options are being compared: 1. `value === undefined`: This operator checks if `value` is equal to the primitive value `undefined`. It's a simple and straightforward way to check for this condition. 2. `typeof value === "undefined"`: This operator checks if the type of `value` is "undefined". However, since `value` is already defined (i.e., not null or undefined), its type will always be `"object"`, not `"undefined"`. **Pros and Cons** * `value === undefined`: + Pros: Simple and straightforward to understand. + Cons: May be slower due to the additional comparison operation. * `typeof value === "undefined"`: + Pros: Can take advantage of type inference and caching by the JavaScript engine. + Cons: Less intuitive and may require more cognitive load to understand. **Library** There doesn't appear to be a specific library used in this benchmark. The code is straightforward JavaScript, relying on the built-in `===` and `typeof` operators. **Special JS Feature or Syntax** There's no special JavaScript feature or syntax being tested in this benchmark. Both options rely on standard language features. **Other Alternatives** If you were to reimplement this benchmark, other alternatives could include: * Using a more sophisticated type system, such as TypeScript. * Incorporating type inference and caching using libraries like ES modules or Babel plugins. * Utilizing specialized JavaScript engines, such as V8's `CheckTypedArray` or SpiderMonkey's `TypeOf` Keep in mind that these alternatives might not directly impact the performance difference between the two options being tested. Overall, this benchmark provides a simple yet informative insight into the performance characteristics of two commonly used JavaScript operators.
Related benchmarks:
Typeof x === 'undefined' vs x === undefined
'value === undefined' VS 'typeof value === "undefined"' when value is defined
Typeof x === 'undefined' vs x === undefined (test without syntax error)
typeof number vs not typeof undefined vs undefined
Comments
Confirm delete:
Do you really want to delete benchmark?