Benchmark: in vs. obj.hasOwnProperty vs prototype.hasOwnProperty.call vs indexer

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };

Tests:

in (true)
'c' in obj;
in (false)
'q' in obj;
obj.hasOwnProperty (true)
obj.hasOwnProperty('c');
obj.hasOwnProperty (false)
obj.hasOwnProperty('q');
prototype.hasOwnProperty.call (true)
Object.prototype.hasOwnProperty.call(obj, 'c');
prototype.hasOwnProperty.call (false)
Object.prototype.hasOwnProperty.call(obj, 'q');
indexer (true)
obj.c
indexer (false)
obj.q

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
in (true)
in (false)
obj.hasOwnProperty (true)
obj.hasOwnProperty (false)
prototype.hasOwnProperty.call (true)
prototype.hasOwnProperty.call (false)
indexer (true)
indexer (false)

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript microbenchmark test case on MeasureThat.net, which compares the performance of different approaches to check if a property exists in an object.

In this benchmark, six different test cases are compared:

1. `in (true)`: Using the `in` operator to check if a property exists in the object.
2. `in (false)`: Using the `in` operator to check if a non-existent property exists in the object.
3. `obj.hasOwnProperty (true)`: Using the `hasOwnProperty()` method of the object itself to check if a property exists.
4. `obj.hasOwnProperty (false)`: Using the `hasOwnProperty()` method to check if a non-existent property exists in the object.
5. `prototype.hasOwnProperty.call (true)`: Using the `hasOwnProperty()` method on the object's prototype, calling it as if it were a function.
6. `prototype.hasOwnProperty.call (false)`: Using the `hasOwnProperty()` method on the object's prototype to check for a non-existent property.

Let's break down each approach:

**1. `in` operator**

The `in` operator is a built-in operator in JavaScript that checks if a property exists in an object or its prototype chain. It returns a boolean value (`true` or `false`) indicating whether the property exists.

Pros: Efficient and simple to use, as it only requires a single operation.

Cons: May not be as intuitive for beginners, and can have performance implications due to the need to traverse the prototype chain.

**2. `hasOwnProperty()` method**

The `hasOwnProperty()` method is a part of the object's prototype (Object.prototype) that checks if a property exists in the object itself.

Pros: More explicit and readable than using the `in` operator, as it clearly indicates which property is being checked.

Cons: May be slower due to the need to call a function on the object.

**3. `prototype.hasOwnProperty.call()`**

This approach uses the `hasOwnProperty()` method on the object's prototype, calling it as if it were a function. This creates a new scope and allows for more explicit control over the lookup process.

Pros: Provides better readability and expressiveness compared to using the `in` operator or `hasOwnProperty()`, while still being efficient.

Cons: May introduce additional overhead due to the creation of a new scope.

The test results show that:

* `in (true)` is generally the fastest approach, followed closely by `prototype.hasOwnProperty.call (true)`.
* `obj.hasOwnProperty (true)` and `obj.hasOwnProperty (false)` are slower than both `in` and `prototype.hasOwnProperty.call()`.
* `indexer (true)` and `indexer (false)` are significantly slower due to the need to access properties directly.

Other alternatives to consider:

* Using `Object.prototype.hasOwnProperty()` instead of `hasOwnProperty()`: This would be similar to option 3, but without the scope creation.
* Using a library like Lodash's `includes()` function: This would provide an additional layer of abstraction and potentially better performance.
* Optimizing for specific use cases: Depending on the context in which this code is used, optimizations like caching or memoization might be possible.

In general, the choice of approach will depend on the trade-offs between readability, maintainability, and performance.

Related benchmarks:

in vs. obj.hasOwnProperty vs prototype.hasOwnProperty.call vs indexer (version: 0)

Object lookup performance

Comparing performance of: in (true) vs in (false) vs obj.hasOwnProperty (true) vs obj.hasOwnProperty (false) vs prototype.hasOwnProperty.call (true) vs prototype.hasOwnProperty.call (false) vs indexer (true) vs indexer (false)

Created: 3 years ago by: Guest

Jump to the latest result

in (true)

in (false)

obj.hasOwnProperty (true)

obj.hasOwnProperty (false)

prototype.hasOwnProperty.call (true)

prototype.hasOwnProperty.call (false)

indexer (true)

indexer (false)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):