Benchmark: undeclared check tests

Tests:

in
var x; 'x' in window 'y' in window
hasOwnProperty
var x; window.hasOwnProperty('x') window.hasOwnProperty('y')
delete
var x; delete x; delete y;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
in
hasOwnProperty
delete

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The provided benchmark measures the performance of three different JavaScript operations:

1. `in` operator
2. `hasOwnProperty` method
3. `delete` operator

These operations are commonly used in JavaScript to check if a property exists or has been deleted from an object.

**Options Compared**

In this benchmark, two options are compared for each operation:

* `in` operator: Checking if a property is present in the `window` object.
	+ Option 1: `'x' in window`
	+ Option 2: `window.hasOwnProperty('x')`
* `hasOwnProperty` method: Checking if an object has a specific property as its own.
	+ Option 1: `window.hasOwnProperty('x')`
	+ Option 2: `window['x'] === undefined`
* `delete` operator: Deleting a property from an object.
	+ Option 1: `delete x`
	+ Option 2: `delete y`

**Pros and Cons of Each Approach**

Here's a brief analysis of each approach:

* **`in` operator**: This is a simple and straightforward way to check if a property exists in the `window` object. However, it can be slow because it involves traversing the object's prototype chain.
	+ Pros: Easy to understand and implement.
	+ Cons: May be slower than other methods due to its nature.
* **`hasOwnProperty` method**: This is a more robust way to check if an object has a specific property as its own. It returns `true` if the property exists, and `false` otherwise.
	+ Pros: More accurate than the `in` operator because it doesn't rely on the prototype chain.
	+ Cons: May be slower due to its additional checks.
* **`delete` operator**: Deleting a property from an object is a simple operation that can be optimized by modern JavaScript engines. However, it may trigger additional checks or garbage collection if not implemented correctly.
	+ Pros: Can be faster than other methods because it's a low-overhead operation.
	+ Cons: May not work as expected in all scenarios due to its simplicity.

**Library and Purpose**

In the provided benchmark, no external libraries are used. However, some built-in JavaScript objects and methods are utilized:

* `window`: The global object that represents the browser window.
* `Object.prototype.hasOwnProperty()`: A method that checks if an object has a specific property as its own.
* `delete` operator: A special operator that removes a property from an object.

**Special JS Features or Syntax**

No special JavaScript features or syntax are used in this benchmark. The operations are straightforward and rely on the basic JavaScript language features.

**Other Alternatives**

If you're interested in exploring alternative approaches, here are some other options:

* **Using `for...in` loop**: Instead of using the `in` operator or `hasOwnProperty` method, you can use a `for...in` loop to iterate over an object's properties.
* **Using `Object.keys()` and `Array.prototype.includes()`**: You can use the `Object.keys()` method to get an array of an object's property names and then use `Array.prototype.includes()` to check if a specific property is present in that array.

These alternative approaches may have different performance characteristics, so it's essential to test them thoroughly to determine which one works best for your specific use case.

Related benchmarks:

undeclared check tests (version: 0)

Comparing performance of: in vs hasOwnProperty vs delete

Created: 6 years ago by: Guest

Jump to the latest result

in

hasOwnProperty

delete

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):