Benchmark: return err vs throw err

Script Preparation code:

function returnErr() {
	return new Error('err');
}

async function returnAsyncErr() {
	await Promise.resolve();
	return new Error('err');
}

function throwErr() {
	throw new Error('err');
}

async function throwAsyncErr() {
	await Promise.resolve();
	throw new Error('err');
}

Tests:

return err
let resultErr = returnErr();
throw err
try { throwErr(); } catch (err) { let resultErr = err; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
return err
throw err

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36

Browser/OS: Chrome 114 on Windows

View result in a separate tab

Test name	Executions per second
return err	244634.2 Ops/sec
throw err	205892.5 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON compares two approaches for handling errors in JavaScript: returning an error object from a function versus throwing an error. Let's break down each approach, the pros and cons, and other considerations.

### Benchmark Overview

1. **Return Error Approach**
   - **Function**: `returnErr` and `returnAsyncErr`
   - **Benchmark Definition**: `let resultErr = returnErr();`
   - **Execution**: This approach simply creates an instance of the `Error` object and returns it from the function.

2. **Throw Error Approach**
   - **Function**: `throwErr` and `throwAsyncErr`
   - **Benchmark Definition**: 
     ```javascript
     try {
       throwErr();
     } catch (err) {
       let resultErr = err;
     }
     ```
   - **Execution**: This approach uses the `throw` statement to raise an error. The error is caught using a `try...catch` block.

### Comparison of Approaches

#### Returning an Error

- **Pros**:
  - **Simplicity**: Returning an error can make the code simpler to read, as the error flow is explicit and manageable.
  - **Control**: The caller can choose how to handle the error without needing to manage a try-catch block.
  - **No Stack Trace**: Returning an error doesn’t create a stack trace, which can be beneficial if the stack trace is not required.
  
- **Cons**:
  - **Manual Error Checking**: The caller must consistently check the returned value to determine if an error occurred, which can lead to oversight if not handled properly.
  - **Loss of Context**: Returning an error does not provide context about where the error originated, as no stack trace is included unless logged independently.

#### Throwing an Error

- **Pros**:
  - **Automatic Handling**: When an exception is thrown, it automatically indicates that something went wrong, which can lead to more straightforward error handling in many situations.
  - **Stack Trace**: When an error is thrown, a stack trace is generated, providing additional context about where the problem occurred, which can be useful for debugging.
  
- **Cons**:
  - **Performance**: Throwing an error can be more performant in terms of execution time when caught, as it requires additional overhead due to the `try...catch` mechanism.
  - **Control Flow Disruption**: Throwing an error disrupts the normal control flow, which can lead to less readable code when there are many nested function calls.

### Benchmark Results

The benchmark results show that:
- The **returning error** method achieved **229,053 executions per second**.
- The **throwing error** method achieved **210,344 executions per second**.

This indicates that returning an error may have a performance edge in this benchmark.

### Other Considerations

- **Concurrency**: If the operations are asynchronous (as with `returnAsyncErr` and `throwAsyncErr`), how errors are managed can become crucial in environments like Node.js, where unhandled rejections can cause processes to terminate.
  
- **Error Types**: Depending on the application, different error types may be returned or thrown, which can influence debugging and management.

### Alternatives

- **Promises**: Employing promises with `.catch()` allows for asynchronous error management while also potentially preserving the stack trace.
  
- **Async/Await with try/catch**: Using async/await with try/catch syntax provides both the readability of synchronous code and error handling capabilities.
  
Ultimately, the choice between returning an error and throwing an error depends on the specific needs of your application, including error handling preference, performance considerations, and overall code structure.

Related benchmarks:

return err vs throw err (version: 1)

Comparing performance of: return err vs throw err

Created: one month ago by: Registered User

Jump to the latest result

return err

throw err

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):