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undefined vs. typeof vs. in vs. hasOwnProperty vs optional chaining
(version: 0)
Object lookup performance
Comparing performance of:
undefined vs typeof vs in vs hasOwnProperty vs bool vs Optional chaining
Created:
4 years ago
by:
Guest
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Script Preparation code:
var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };
Tests:
undefined
undefined !== obj.d;
typeof
'undefined' !== typeof obj.d;
in
'd' in obj;
hasOwnProperty
obj.hasOwnProperty( 'd' );
bool
!! obj.d;
Optional chaining
undefined !== obj?.d;
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (6)
Previous results
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Test case name
Result
undefined
typeof
in
hasOwnProperty
bool
Optional chaining
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
**Benchmark Overview** The MeasureThat.net benchmark tests the performance of various JavaScript operators for object lookup: `undefined`, `typeof`, `in`, `hasOwnProperty`, and optional chaining (`?.`). The benchmark compares these different approaches to check if a property exists in an object. **Operators Compared** 1. **`undefined`**: Checks if a variable is equal to `undefined`. 2. **`typeof`**: Returns the type of a variable (e.g., "number", "string", etc.). 3. **`in`**: Checks if a property exists in an object using the `in` operator. 4. **`hasOwnProperty`**: Checks if an object has a specified property as its own property, rather than inheriting it from its prototype chain. 5. **Optional chaining (`?.`)**: A new feature introduced in JavaScript (ECMAScript 2020) that allows safe navigation of nested properties. **Pros and Cons** * **`undefined`**: Simple and straightforward but can be slow for large objects or complex lookups. + Pros: Easy to implement, high-level abstraction. + Cons: May not work as expected if the object is not initialized properly. * **`typeof`**: Fast and efficient but returns the type of a variable, not just whether it exists. + Pros: Quick execution time, useful for type checking. + Cons: Returns additional information that may not be relevant to the lookup operation. * **`in`**: Fast and reliable but has limitations (e.g., does not work with `undefined` values). + Pros: Fast execution time, works well for simple lookups. + Cons: May produce false positives if the object is not properly initialized. * **`hasOwnProperty`**: Reliable and precise but slower than `in`. + Pros: Works correctly even when the object's prototype chain is involved. + Cons: Slower execution time due to additional checks. * **Optional chaining (`?.`)**: Safe and efficient but relatively new feature (ECMAScript 2020). + Pros: Ensures safe navigation of nested properties, fast execution time. + Cons: Requires support for ECMAScript 2020 or later. **Library** None explicitly mentioned in the benchmark definition. However, `obj` is an object literal created using JavaScript syntax, which implies that no external library was used to create it. **Special JS Features/Syntax** No special features or syntax are mentioned in the provided benchmark.
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undefined vs. typeof vs. in vs. hasOwnProperty
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undefined vs. typeof vs. in vs. hasOwnProperty big object
undefined vs. typeof vs. in vs. hasOwnProperty vs. Optional chaining
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