Benchmark: Function creation from text - eval vs new Function

Tests:

eval
var x = eval("(function (a,b){ return a * b})"); x(4,5)
new Function
var func = new Function("a","b","return a * b"); func(4,5);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
eval
new Function

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.110 Safari/537.36

Browser/OS: Chrome 96 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
eval	5863143.5 Ops/sec
new Function	2285256.5 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the JavaScript microbenchmark you provided.

**Benchmark Overview**

The benchmark compares two approaches for creating and executing a simple mathematical function in JavaScript:

1. `eval`
2. `new Function`

**What is being tested?**

In this benchmark, we're measuring the execution time of creating a function from text using both `eval` and `new Function`. The function takes two arguments, multiplies them together, and returns the result.

**Options compared**

The main difference between these two approaches is how they handle the creation and execution of the function:

* `eval`: This method parses the provided string as JavaScript code and executes it immediately. In this case, we're passing a string literal that defines a function with two parameters.
* `new Function`: This method creates a new function object dynamically using the provided string. The newly created function can then be invoked like any other function.

**Pros and Cons**

Here are some pros and cons of each approach:

### eval

Pros:

* More flexible, as you can pass arbitrary JavaScript code
* Can be faster for simple expressions (since it's just parsing and executing)

Cons:

* Security risks if the input string is not sanitized or validated
* Can lead to performance issues with large or complex expressions
* Less control over the creation process

### new Function

Pros:

* Provides more control over the function creation process
* Avoids security risks by executing a separate, sandboxed code block
* More predictable and efficient for small, well-defined functions

Cons:

* Requires additional overhead due to creating a new function object
* May be slower than `eval` for very simple expressions

**Library usage**

In this benchmark, no external library is used.

**Special JS feature or syntax**

There are no special JavaScript features or syntaxes mentioned in the provided benchmark.

**Alternatives**

If you need to create and execute functions dynamically, other alternatives could include:

* `Function constructor`: A similar approach to `new Function`, but with more flexibility and control.
* `Abstract Syntax Tree (AST) libraries**: Libraries like esprima or acorn can parse JavaScript code into an AST, which can then be executed using a custom interpreter.
* **Just-In-Time (JIT) compilers**: Some frameworks, like React or Angular, use JIT compilation to optimize performance. While not directly applicable to this benchmark, they demonstrate the importance of efficient function creation and execution.

**Benchmark preparation code**

The provided `Script Preparation Code` is empty, which means that the benchmark script should be defined in a separate file or string literal. The `Html Preparation Code` is also empty, suggesting that the benchmark doesn't rely on any specific HTML structure.

For this particular benchmark, you can create a simple JavaScript function and pass it to `eval` or `new Function`, like so:
```javascript
var func = eval("(function (a,b){ return a * b})");
func(4, 5);
```
Or, using `new Function`:
```javascript
var func = new Function("a", "b", "return a * b;");
func(4, 5);
```
These scripts can be executed by MeasureThat.net to generate the benchmark results.

Related benchmarks:

Function creation from text - eval vs new Function (version: 0)

Comparing performance of: eval vs new Function

Created: 3 years ago by: Guest

Jump to the latest result

eval

new Function

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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