Benchmark: eval vs new Function vs vanilla

Script Preparation code:

var func = new Function("return 2 * 3");
function func2() { return 2 * 3; }

Tests:

eval
eval("2 * 3");
new Function
func();
vanilla
func2();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
eval
new Function
vanilla

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/115.0

Browser/OS: Firefox 115 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
eval	5072463.0 Ops/sec
new Function	743686272.0 Ops/sec
vanilla	744881280.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what each section represents.

**Benchmark Definition**

The `Name`, `Description`, `Script Preparation Code`, and `Html Preparation Code` sections define the benchmark. In this case, we have three different scripts that will be tested:

* `new Function("return 2 * 3;");`: Creates a new function using the `Function` constructor, which takes a string argument containing the expression to evaluate.
* `function func() { return 2 * 3; }`: Defines an anonymous function with a single expression inside it. This is a classic example of "vanilla" JavaScript, where we define functions using the `function` keyword.
* `eval("2 * 3");`: Uses the built-in `eval` function to evaluate a string expression.

**Options Compared**

The three scripts being compared are:

1. **new Function**: Creates a new function using the `Function` constructor.
2. **vanilla**: Defines an anonymous function using the `function` keyword.
3. **eval**: Uses the built-in `eval` function to evaluate a string expression.

**Pros and Cons**

Here's a brief summary of each approach:

* **new Function**: This method creates a new scope for the evaluation, which can prevent some optimizations from working. However, it also provides more flexibility in terms of error handling and code organization.
* **vanilla**: This is the most straightforward way to define functions and evaluate expressions. It's often preferred for its simplicity and lack of performance overhead.
* **eval**: While `eval` can be powerful, it's generally considered a bad practice due to security concerns (e.g., evaluating user input) and potential performance issues.

**Library: Function**

The `Function` constructor is a built-in JavaScript function that creates a new function. Its purpose is to provide flexibility in defining functions, especially when working with strings or dynamically generated code.

**Special JS Feature/Syntax**

None mentioned directly, but the use of `eval` might be considered an advanced topic, as it can have security implications if not used carefully.

**Other Alternatives**

If you wanted to compare these approaches without using `eval`, you could consider alternative methods for evaluating expressions, such as:

* Using a parser like Esprima or AmdJs
* Utilizing libraries like MathJax or TeX.js for mathematical expressions
* Implementing a custom expression evaluator using JavaScript engines like V8

Keep in mind that these alternatives might add complexity and performance overhead compared to the original approach.

For a wide range of software engineers, understanding the basics of function creation, evaluation, and optimization is essential. The comparison between `new Function`, vanilla functions, and `eval` helps demonstrate key concepts, such as:

* Code organization and scope management
* Performance considerations (e.g., function overhead, string evaluation)
* Best practices for evaluating expressions in JavaScript

I hope this explanation helps!

Related benchmarks:

eval vs new Function vs vanilla (version: 0)

Comparing performance of: eval vs new Function vs vanilla

Created: one year ago by: Guest

Jump to the latest result

eval

new Function

vanilla

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):