Benchmark: window.eval function vs new Function

Tests:

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

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: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
eval	0.0 Ops/sec
new Function	2345037.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**What is being tested?**

The provided JSON represents two JavaScript microbenchmarks that compare the performance of two approaches:

1. **`window.eval` function**: This method executes a string as JavaScript code, returning its result. In contrast to `new Function()`, it does not parse or execute the code in the context of an existing scope.
2. **`new Function()`**: This method creates a new JavaScript function object from a given string, allowing for execution and parsing in the context of an existing scope.

**Options being compared:**

The two approaches differ in how they handle:

1. **Execution context**: `window.eval()` executes the code without creating a separate scope, while `new Function()` creates a new function object with its own scope.
2. **Code parsing**: Both methods parse the input string into an Abstract Syntax Tree (AST), but `new Function()` also performs type checking and variable lookup.

**Pros and cons of each approach:**

1. **`window.eval` function**:
	* Pros: faster execution time, as it avoids creating a new scope.
	* Cons:
		+ Potential security risks if used with untrusted input, as it can execute arbitrary code in the global scope.
		+ Limited support for variables and scoping.
2. **`new Function()`**:
	* Pros:
		+ Safer execution, as it executes in a separate scope and avoids potential security risks.
		+ Supports variables and scoping.
	* Cons:
		+ Slower execution time due to the additional parsing and context creation.

**Library usage:**

None of the provided benchmarks use any external libraries. However, if you were to add code that uses a library like `ES6` or `ECMAScript`, it would be used for features like arrow functions, classes, or async/await syntax.

**Special JS feature/syntax:**

The provided benchmarks do not use any special JavaScript features or syntax beyond the standard ECMAScript syntax.

**Other alternatives:**

If you wanted to test other approaches, consider:

1. **`Function()` constructor**: Similar to `new Function()`, but may have performance advantages due to its optimized implementation.
2. **`eval()` with a scope object**: Instead of using the global scope, use an explicit scope object to control variable lookup and execution context.

When creating your own benchmark, consider factors like:

* Using a consistent test framework (e.g., `BenchmarkJS`)
* Minimizing overhead from additional libraries or features
* Carefully designing test cases to isolate the effects of each approach
* Analyzing results with care, considering factors like environment, hardware, and interpreter variations.

Related benchmarks:

window.eval function vs new Function (version: 0)

Comparing performance of: eval vs new Function

Created: 4 years ago by: Guest

Jump to the latest result

eval

new Function

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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