Benchmark: eval vs new Function (fix)

Script Preparation code:

var func = new Function("return 2 * 3");

Tests:

eval
eval("(function(){ return 2 * 3})();");
new Function
(new Function("return 2 * 3;"))();

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: 25 days ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 131 on Android

View result in a separate tab

Test name	Executions per second
eval	1644748.4 Ops/sec
new Function	637940.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explore what's being tested in this specific benchmark.

**What is being tested?**

The provided JSON represents two test cases that compare the performance of `eval` versus `new Function` in creating a simple arithmetic expression. The benchmarks are designed to measure which approach is faster, more efficient, or has better performance characteristics.

**Options compared:**

Two options are being compared:

1. **`eval`**: A built-in JavaScript function that parses and executes a string as JavaScript code.
2. **`new Function`**: A constructor function used to create a new function object with a given string of JavaScript code.

**Pros and Cons of each approach:**

* `eval`:
	+ Pros:
		- Easy to use, as it's a built-in function that can be called directly.
		- Can evaluate arbitrary JavaScript expressions.
	+ Cons:
		- Performance overhead due to parsing and executing the string as code.
		- May introduce security vulnerabilities if not used carefully (e.g., evaluating user-input data).
* `new Function`:
	+ Pros:
		- More flexible than `eval`, as it allows creating a new function with specific parameters.
		- Can be used to create functions with a more structured syntax.
	+ Cons:
		- May have additional overhead due to the creation of a new function object.

**Library and purpose:**

There is no library being used in this benchmark. The `new Function` approach is a built-in JavaScript feature that's part of the language.

**Special JS features or syntax:**

None are mentioned explicitly, but `eval` can be affected by some special cases, such as:

* **Closures**: When using `eval`, it can create closures with the surrounding scope, which may have unexpected effects.
* **Scope chains**: `new Function` can create a new scope chain for the created function, which might be desirable or undesirable depending on the use case.

**Other alternatives:**

If you're looking for alternative approaches to creating simple arithmetic expressions in JavaScript, some options include:

* Using template literals (`let result = 2 * 3;`)
* Using a library like `mathjs` or `numjs` for numerical computations.
* Using a function expression with a single line of code (e.g., `function add(x, y) { return x + y; }()`)

Keep in mind that these alternatives might not be as straightforward as using `eval` or `new Function`, but they can offer more control over the computation process and potentially better performance.

I hope this explanation helps software engineers understand what's being tested in this JavaScript microbenchmark!

Related benchmarks:

eval vs new Function (fix) (version: 0)

Comparing performance of: eval vs new Function

Created: 3 years ago by: Registered User

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):