Benchmark: instanceof Vector

Script Preparation code:

class Vector {
    constructor() {
        this.x = 0
    }
}
var vec = new Vector()

Tests:

instanceof
vec instanceof Map
typeof
typeof vec === 'object'
property
vec.x != null
isArray
Array.isArray(vec)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceof
typeof
property
isArray

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.

**What is tested in the provided JSON?**

The provided JSON represents a JavaScript microbenchmark created on MeasureThat.net. It includes:

1. **Benchmark definition**: A JavaScript class `Vector` with a constructor that initializes an `x` property to 0.
2. **Script preparation code**: The class definition and creation of a new instance of the `Vector` class, named `vec`.
3. **Html preparation code**: None specified in this benchmark.

The test cases are designed to measure the execution time of different JavaScript operators or checks on the `vec` object:

1. `instanceof Map`: Checks if the `vec` object is an instance of the `Map` constructor.
2. `typeof vec === 'object'`: Checks the type of the `vec` variable using the `typeof` operator, which returns the "object" type for objects and null values.
3. `vec.x != null`: Checks if the `x` property of the `vec` object is not null or undefined.
4. `Array.isArray(vec)`: Checks if the `vec` variable is an array using the `Array.isArray()` function.

**Options compared**

The test cases compare the execution time of different approaches to check properties or types:

1. **`instanceof` operator**: Compares the use of the `instanceof` operator to check the type of an object.
2. **`typeof` operator**: Compares the use of the `typeof` operator to check the type of a variable.
3. **Property checks**: Compares the use of property checks (e.g., `vec.x != null`) to check for specific values.

**Pros and cons**

Here are some pros and cons of each approach:

1. **`instanceof` operator**:
	* Pros: Can be more efficient for checking if an object is a specific type.
	* Cons: May not work as expected with derived classes or complex object hierarchies.
2. **`typeof` operator**:
	* Pros: Can provide a more general way to check the type of a variable, including null and undefined values.
	* Cons: May be slower than using `instanceof` for certain types (e.g., functions).
3. **Property checks**:
	* Pros: Provides a clear way to check specific properties or values in an object.
	* Cons: Can lead to more complex code and may not be as efficient as other approaches.

**Libraries and syntax**

None of the test cases use any libraries, but they do use built-in JavaScript operators and functions (e.g., `Array.isArray()`).

**Special JS features or syntax**

The only special feature in this benchmark is the use of a class definition (`class Vector { ... }`) and an instance creation (`var vec = new Vector()`). This is modern JavaScript syntax that allows for object-oriented programming.

**Other alternatives**

Other approaches to check properties or types might include:

* Using `Object.prototype.hasOwnProperty.call()`
* Using `JSON.stringify()` with the `null` argument
* Using a library like Lodash's `isPlainObject()` function

Keep in mind that these alternatives may have different performance characteristics and trade-offs compared to the approaches tested in this benchmark.

Related benchmarks:

instanceof Vector (version: 1)

Comparing performance of: instanceof vs typeof vs property vs isArray

Created: 3 years ago by: Registered User

Jump to the latest result

instanceof

typeof

property

isArray

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):