Benchmark: eval vs new Function vs Script Blob

Script Preparation code:

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

Tests:

eval
eval("2 * 3");
new Function
func();
Script Blob
var _script = document.createElement('SCRIPT'); var _url = URL.createObjectURL(new Blob(["return 2 * 3"], { type: 'text/javascript' })); _script.src = _url; document.body.appendChild(_script); URL.revokeObjectURL(_url); _script.remove();

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

new Function

49.4M/s

eval

3.6M/s

Script Blob

816/s

Fastest: new Function (60578.9x faster)

View exact numbers

✓ new Function: 49,402,472 ops/sec
• eval: 3,567,026 ops/sec
• Script Blob: 816 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
eval
new Function
Script Blob

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 135 on Android

View result in a separate tab

new Function

83.2M/s

eval

4.6M/s

Script Blob

389/s

View exact numbers

Test name	Executions per second
✓ new Function	83,195,416 Ops/sec
eval	4,581,632 Ops/sec
Script Blob	389 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and its test cases, explaining what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares the performance of three different approaches to execute a simple JavaScript expression:

1. `eval`: Directly evaluates the expression using the built-in `eval` function.
2. `new Function`: Creates a new function object using the `Function` constructor and then calls it with the desired arguments.
3. Script Blob: Creates a script blob (a blob of JavaScript code) that can be executed by the browser without requiring an explicit function call.

**Test Case 1: eval**

The first test case uses the built-in `eval` function to execute the expression `"2 * 3"`. This is a simple and straightforward approach, but it may have performance implications due to security restrictions and potential overhead.

Pros:

* Easy to implement
* Widely supported

Cons:

* May incur additional overhead or security restrictions
* Can be slower than other approaches

**Test Case 2: new Function**

The second test case uses the `Function` constructor to create a new function object with the expression `"return 2 * 3"` as its body. The resulting function is then called using the parentheses `()`.

Pros:

* Allows for more control over the execution environment
* Can be faster than `eval`

Cons:

* May incur additional overhead due to function creation and call
* Requires explicit function call

**Test Case 3: Script Blob**

The third test case uses a script blob (a blob of JavaScript code) that is created using the `URL.createObjectURL` method. The script blob contains the expression `"return 2 * 3"` as its content. The script blob is then executed by setting its `src` attribute and appending it to the document body.

Pros:

* Allows for execution without explicit function call
* Can be faster than other approaches

Cons:

* May incur additional overhead due to blob creation and execution
* Requires knowledge of URL-based JavaScript execution

**Library: None**

There are no libraries used in this benchmark. However, note that some browsers may use internal libraries or engines that can affect the performance of these approaches.

**Special JS Features/Syntax: None**

None of the test cases rely on special JavaScript features or syntax. The focus is solely on comparing the performance of the three different execution approaches.

**Other Alternatives**

Some alternative approaches to executing JavaScript expressions include:

* `Function.prototype.call()`: Calls a function object using its `call` method, passing in arguments.
* `evalAt()`: A non-standard method that allows evaluating an expression at a specific context (not widely supported).
* Just-In-Time (JIT) compilation: Some engines, like SpiderMonkey, can JIT compile JavaScript expressions for improved performance.

Keep in mind that the choice of approach often depends on the specific use case and requirements.

eval vs new Function vs Script Blob (version: 0) Benchmark.js

Comparing performance of: `eval vs new Function vs Script Blob`

Created: 5 years ago by: Guest

Go to the latest result

eval

new Function

Script Blob

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

eval vs new Function vs Script Blob (version: 0) Benchmark.js

Comparing performance of: eval vs new Function vs Script Blob

Created: 5 years ago by: Guest

Go to the latest result

eval

new Function

Script Blob

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `eval vs new Function vs Script Blob`