Benchmark: Split vs Substring + IndexOf

HTML Preparation code:

<div id='xx'></div>

Script Preparation code:

let email = 'TestUser2137@example.com';
let times = 1000;

Tests:

Split
let x = 0; while (x < times) { const userName = email.split('@')[0]; console.log(userName); x += 1; }
Substring
let x = 0; while (x < times) { const userName = email.substring(0, email.indexOf('@')); console.log(userName); x += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Split
Substring

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 days ago):

LLMs can make mistakes. Check important info.

This benchmark evaluates the performance of two different techniques for extracting the username from an email string: using the `split` method versus a combination of the `substring` method and the `indexOf` method. Here's a detailed breakdown of what is being tested and the implications of each approach.

### Tested Options

1. **Split Method**:
   - **Code**: 
     ```javascript
     const userName = email.split('@')[0];
     ```
   - This approach splits the email string into an array where the first element is the part before the '@' character (the username). The `split` method is straightforward and often perceived as the most intuitive way to break a string into parts based on a delimiter.

2. **Substring + IndexOf Method**:
   - **Code**:
     ```javascript
     const userName = email.substring(0, email.indexOf('@'));
     ```
   - Here, the function first finds the position of the '@' character using `indexOf`, and then extracts the substring from the beginning of the email string up to that position using `substring`. This method has a bit more complexity since it involves multiple steps.

### Pros and Cons

#### Split Method:
- **Pros**:
  - Simple syntax: Very readable and intuitive for extracting the username.
  - Handles multiple '@' characters gracefully (returns the first part only).
  
- **Cons**:
  - May create an array in memory, which involves a bit of overhead, especially if this operation is performed repeatedly in a loop.

#### Substring + IndexOf Method:
- **Pros**:
  - This method can be faster due to the direct extraction of a substring without creating an intermediate array.
  - Offers more control, for example, if you want to handle cases with no '@' character differently.

- **Cons**:
  - Slightly more complex and less readable than the split approach.
  - Requires two operations (finding the index and getting the substring), which might be less efficient in some scenarios.

### Benchmark Results
Based on the results provided:
- **Split**: Approximately 224.81 executions per second.
- **Substring**: Approximately 204.88 executions per second.

The benchmark results indicate that using `split` had a higher execution count per second compared to using `substring` with `indexOf`. However, the performance can vary based on several factors, including the JavaScript engine used and string complexity.

### Additional Considerations
- **Browser and Environment**: Performance can depend on the underlying JavaScript engine, which varies across different browsers. This benchmark was executed in Chrome, which generally has robust JS optimization.

- **Use Cases**: If the operation is used in performance-critical paths, such as in tight loops or high-frequency calls, the slight differences in execution speed can accumulate. Therefore, where performance is critical, profiling in the specific environment is advisable.

### Alternatives
- **Regular Expressions**: Another approach for extracting the username could involve using regular expressions (e.g., using `email.match(/^(.*)@/)`). This method can be very powerful and flexible but may introduce overhead and complexity for simpler cases.

- **String Methods**: Other string manipulation methods (e.g., `lastIndexOf`, various slicing functions) could also be employed, depending on specific needs in parsing formats.

In summary, this benchmark provides useful insights into two popular string parsing techniques in JavaScript, with distinct trade-offs between simplicity, performance, and memory usage. A deeper understanding of the context in which these operations will be implemented can guide the best choice between them.

Latest run results:

Run details: (Test run date: 2 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Edg/131.0.0.0

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
Split	224.8 Ops/sec
Substring	204.9 Ops/sec

Related benchmarks:

Split vs Substring + IndexOf (version: 1)

Comparing performance of: Split vs Substring

Created: 2 days ago by: Guest

Jump to the latest result

Split

Substring

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 days ago):