Benchmark: eval vs new Function v3

Script Preparation code:

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

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
eval
new Function
func

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36

Browser/OS: Chrome 77 on Linux

View result in a separate tab

Test name	Executions per second
eval	1784745.9 Ops/sec
new Function	10942080.0 Ops/sec
func	621493568.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark is defined in two parts: `Script Preparation Code` and `Html Preparation Code`. The latter is empty, so we'll focus on the former.

The script preparation code is a piece of JavaScript that creates a new function using the `new Function()` constructor. This function takes a string literal as an argument and returns the result of evaluating that string as JavaScript code. In this case, the string is `"return 2 * 3"`.

This means we have three test cases:

1. `eval("2 * 3");` - uses the built-in `eval()` function to execute the string as JavaScript code.
2. `func();` - calls a newly created function using the `new Function()` constructor, passing the same string literal as an argument.
3. `function fff() { return 2 * 3; }` - creates a new anonymous function using the function declaration syntax.

**Options Compared**

We're comparing three approaches:

1. **eval()**: executes a string as JavaScript code at runtime.
2. **new Function()**: creates a new function and calls it with the provided argument (in this case, the string literal).
3. **Function Declaration**: creates a new anonymous function using the function declaration syntax.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **eval()**:
	* Pros: easy to use, flexible.
	* Cons: can be a security risk if used with untrusted input, performance overhead.
2. **new Function()**:
	* Pros: creates a new function that can be reused, avoids some security concerns of `eval()`.
	* Cons: requires a string literal as an argument, might not be as efficient as other approaches.
3. **Function Declaration**:
	* Pros: explicit, readable syntax, no overhead from creating a function object.
	* Cons: not suitable for all use cases (e.g., when you need to pass arbitrary code as an argument).

**Libraries and Special JS Features**

There are no libraries involved in this benchmark.

**Special JS Features**

There is one special feature being tested:

1. **Function Expressions**: The `new Function()` constructor uses function expressions, which were introduced in ECMAScript 5 (2015). This syntax allows creating anonymous functions that can be executed later.

**Alternative Approaches**

Some alternative approaches to benchmarking this code might include:

* Using a more modern approach like using an Immediately Invoked Function Expression (IIFE): `(function() { var func = new Function("return 2 * 3"); return func(); })()`
* Measuring the performance of different JavaScript engines or versions
* Comparing the performance of `eval()` with other alternatives, such as `Function constructor` or `parser.parseScript`

These alternative approaches would require modifications to the benchmark code and might provide more detailed insights into the performance characteristics of each approach.

Related benchmarks:

eval vs new Function v3 (version: 0)

Comparing performance of: eval vs new Function vs func

Created: 5 years ago by: Guest

Jump to the latest result

eval

new Function

func

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):