Benchmark: in !== hasOwnProperty

Script Preparation code:

const vUserInfo = {cMemberId: 1}

Tests:

"cMemberId" in vUserInfo
const vUserInfo = {cMemberId: 1} "cMemberId" in vUserInfo
vUserInfo.cMemberId !== undefined
const vUserInfo = {cMemberId: 1} vUserInfo.cMemberId !== undefined
vUserInfo.cMemberId === undefined
const vUserInfo = {cMemberId: 1} vUserInfo.cMemberId === undefined
vUserInfo.hasOwnProperty("cMemberId")
const vUserInfo = {cMemberId: 1} vUserInfo.hasOwnProperty("cMemberId")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
"cMemberId" in vUserInfo
vUserInfo.cMemberId !== undefined
vUserInfo.cMemberId === undefined
vUserInfo.hasOwnProperty("cMemberId")

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is defined in JSON, which provides the following information:

* `Name`: The name of the benchmark ("in !== hasOwnProperty").
* `Description`: A brief description of the benchmark (none provided).
* `Script Preparation Code`: A script that sets up the variables for the benchmark. In this case, it creates an object `vUserInfo` with a single property `cMemberId` and initializes its value to 1.
* `Html Preparation Code`: An empty string, which means no HTML code is required to set up the environment.

**Individual Test Cases**

The benchmark consists of four test cases, each defined in a separate JSON object. Each test case has:

* `Benchmark Definition`: The actual JavaScript code that's being tested.
* `Test Name`: A human-readable name for the test case.

Here are the individual test cases, explained:

1. `"const vUserInfo = {cMemberId: 1}\r\n\"cMemberId\" in vUserInfo"`
	* This test checks whether the property `cMemberId` exists in the object `vUserInfo`. The `in` operator is used to check if a property exists in an object.
2. `"const vUserInfo = {cMemberId: 1}\r\nvUserInfo.cMemberId !== undefined"`
	* This test checks whether the value of `cMemberId` in the object `vUserInfo` is not equal to `undefined`.
3. `"const vUserInfo = {cMemberId: 1}\r\nvUserInfo.cMemberId === undefined"`
	* This test checks whether the value of `cMemberId` in the object `vUserInfo` is equal to `undefined`. Note that this test has a different comparison operator (`===`) than the previous one, which uses the not-equal (`!==`) operator.
4. `"const vUserInfo = {cMemberId: 1}\r\nvUserInfo.hasOwnProperty(\"cMemberId\")"`
	* This test checks whether the property `cMemberId` exists in the object `vUserInfo` using the `hasOwnProperty` method.

**Options Compared**

The benchmark is testing four different approaches to check if a property exists in an object:

1. Using the `in` operator (`"cMemberId" in vUserInfo`).
2. Using the not-equal comparison with `undefined` (`vUserInfo.cMemberId !== undefined`).
3. Using the equal comparison with `undefined` (`vUserInfo.cMemberId === undefined`).
4. Using the `hasOwnProperty` method (`vUserInfo.hasOwnProperty("cMemberId")`).

**Pros and Cons of Each Approach**

Here's a brief summary of each approach:

1. **Using `in` operator**: This approach is simple and straightforward. However, it may not be as efficient as other methods, especially for large objects.
	* Pros: Easy to read and write, doesn't require the object itself.
	* Cons: May not be as efficient, can lead to unexpected results if the property name is a reserved word.
2. **Not-equal comparison with `undefined`**: This approach checks if the property exists by verifying that its value is not `undefined`.
	* Pros: More efficient than using `in`, doesn't require the object itself.
	* Cons: May not be as straightforward to read, requires more operations.
3. **Equal comparison with `undefined`**: This approach checks if the property exists by verifying that its value is equal to `undefined`.
	* Pros: Similar to not-equal comparison, but may be more intuitive for some developers.
	* Cons: Less efficient than not-equal comparison, may lead to unexpected results if the property has a different type (e.g., null).
4. **Using `hasOwnProperty` method**: This approach checks if the object has the specified property as its own property, rather than inheriting it from a prototype chain.
	* Pros: More explicit and intuitive, doesn't require comparing with `undefined`.
	* Cons: May not be as efficient as other methods, can lead to unexpected results if the property is inherited.

**Other Considerations**

When working with objects in JavaScript, there are several other considerations:

* **Prototype chains**: When accessing properties on an object, JavaScript checks the object's prototype chain for the property. This means that if a property is inherited from a parent object, it will be found first.
* **Null and undefined**: In JavaScript, `null` and `undefined` are distinct values that represent the absence of any value. It's essential to handle these cases correctly when working with objects.

**Alternatives**

If you're interested in exploring alternative approaches or optimizing performance, here are some additional options:

* Use a more efficient data structure, such as an object literal with `const` declarations.
* Use a library like Lodash, which provides optimized functions for common tasks like property checking and iteration.
* Consider using a static type checker or code analyzer to identify potential issues and optimize your code.

I hope this explanation helps!

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.117 Safari/537.36

Browser/OS: Chrome 79 on Windows

View result in a separate tab

Test name	Executions per second
"cMemberId" in vUserInfo	801729856.0 Ops/sec
vUserInfo.cMemberId !== undefined	6710255.5 Ops/sec
vUserInfo.cMemberId === undefined	6695760.5 Ops/sec
vUserInfo.hasOwnProperty("cMemberId")	93191984.0 Ops/sec

Related benchmarks:

in !== hasOwnProperty (version: 0)

Comparing performance of: "cMemberId" in vUserInfo vs vUserInfo.cMemberId !== undefined vs vUserInfo.cMemberId === undefined vs vUserInfo.hasOwnProperty("cMemberId")

Created: 4 years ago by: Guest

Jump to the latest result

"cMemberId" in vUserInfo

vUserInfo.cMemberId !== undefined

vUserInfo.cMemberId === undefined

vUserInfo.hasOwnProperty("cMemberId")

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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