Benchmark: InstanceOf vs String type vs Number type

HTML Preparation code:

<script>
class TestClass {
    constructor() {
        this.a = 2;
        this.t = 'mesh';
    }
}
</script>

Script Preparation code:

var obj = new TestClass();

Tests:

instanceof
obj instanceof TestClass;
string type
obj.t === 'mesh'
string type + undefined
obj.t !== undefined
Number property
obj.a == 2

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceof
string type
string type + undefined
Number property

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Windows

View result in a separate tab

Test name	Executions per second
instanceof	115061000.0 Ops/sec
string type	124998824.0 Ops/sec
string type + undefined	118310672.0 Ops/sec
Number property	114443312.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its components.

**Benchmark Definition**
The benchmark compares three different approaches to compare a value with `undefined`:

1. `obj.t === 'mesh'`: This is a basic string comparison using the strict equality operator (`===`). It checks if the value of `t` is equal to the exact string `'mesh'`.
2. `obj.t !== undefined`: This compares the value of `t` with `undefined`. If `t` has any other value, this expression will return true.
3. `instanceof TestClass`: This uses the `instanceof` operator to check if the object `obj` is an instance of the class `TestClass`.

**Options Compared**
The three options are compared in terms of their execution time.

**Pros and Cons of Each Approach:**

1. **Basic String Comparison (`obj.t === 'mesh'`)**:
	* Pros: Simple, efficient, and effective for comparing exact string values.
	* Cons: May not work as expected if `t` is a non-ASCII character or has Unicode escape sequences.
2. **Comparing with `undefined` (`obj.t !== undefined`)**:
	* Pros: More flexible than basic string comparison, handles different data types and can be useful for null checks.
	* Cons: May not be as efficient as basic string comparison and may have performance implications in certain cases.
3. **Using `instanceof` Operator (`instanceof TestClass`)**:
	* Pros: Can be used to check the type of an object without requiring manual value comparisons.
	* Cons: More complex than basic string comparison or comparing with `undefined`, can lead to unexpected behavior if not used correctly.

**Library Used**
The benchmark uses a custom JavaScript class, `TestClass`, which is defined in the script preparation code:

```javascript
class TestClass {
    constructor() {
        this.a = 2;
        this.t = 'mesh';
    }
}
```

This class has two properties: `a` (an integer) and `t` (a string). The benchmark creates an instance of this class, `obj`, which is used as the test object.

**Special JS Feature/Syntax**
The benchmark does not use any special JavaScript features or syntax beyond what's typically available in modern browsers. However, it's worth noting that some older browsers might have issues with the `instanceof` operator or other aspects of this benchmark.

**Alternatives**
Other alternatives to these approaches could include:

* Using a library like Lodash's `isEqual` function to compare values.
* Implementing a custom comparison function using bitwise operations or other low-level techniques.
* Using a different type system, such as TypeScript, which can provide more robust and expressive type checking.

Keep in mind that the choice of approach will depend on the specific requirements and constraints of the use case.

Related benchmarks:

InstanceOf vs String type vs Number type (version: 0)

Measure the performance of instanceOf operator vs comparing a basic string type.

Comparing performance of: instanceof vs string type vs string type + undefined vs Number property

Created: one year ago by: Guest

Jump to the latest result

instanceof

string type

string type + undefined

Number property

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):