Benchmark: String vs direct property access

Script Preparation code:

class A {
    someValue = 0
}
var a = new A()
a.someValue = Math.random() * 1000000
var propertyName = "someValue"

Tests:

Direct access
a.someValue
String
a[propertyName]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Direct access
String

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.

Let's break down the provided JSON benchmark definition and test cases to understand what is being tested.

**Benchmark Definition**

The JSON defines a benchmark called "String vs direct property access". The purpose of this benchmark is to compare the performance of accessing a property using its name (direct property access) versus using bracket notation with a string (property name).

**Script Preparation Code**

The script preparation code creates an instance of class `A` and assigns a random value between 0 and 1,000,000 to a property named `someValue`. The HTML preparation code is empty.

**Individual Test Cases**

There are two test cases:

1. **Direct access**: This test case uses the dot notation (`a.someValue`) to access the property.
2. **String**: This test case uses bracket notation with a string (`a[propertyName]`) to access the property.

**Library and its purpose (if used)**

In this benchmark, the `Math.random()` function is used, which is a built-in JavaScript library. Its purpose is to generate random numbers.

**Special JS feature or syntax**

There are no special features or syntaxes mentioned in the provided code snippet.

**Pros and Cons of different approaches**

1. **Direct access (a.someValue)**:
	* Pros: Often faster due to compiler optimizations, fewer operations required.
	* Cons: May not be supported by all browsers or environments.
2. **String**: (using bracket notation with a string)
	* Pros: More forgiving for typos or property name changes, can work in environments where direct access is not allowed.
	* Cons: May require more operations and computations, potentially slower.

**Other considerations**

When using bracket notation, the JavaScript engine needs to perform additional steps to find the property, which may result in a slight performance overhead. However, this approach provides better protection against typos or property name changes, making it a safer choice.

In general, when deciding between direct access and bracket notation, consider the following:

* Use direct access if you need raw speed and are confident that the property name will not change.
* Use bracket notation with a string if you want to provide some protection against typos or property name changes.

**Other alternatives**

If you need to measure the performance of other approaches, such as using `in` operator (e.g., `a.hasOwnProperty(propertyName)`), consider adding additional test cases.

Related benchmarks:

String vs direct property access (version: 0)

Comparing performance of: Direct access vs String

Created: 3 years ago by: Guest

Jump to the latest result

Direct access

String

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):