Benchmark: slice vs substr vs substring (with no end index)

Script Preparation code:

var example = 'there is no spoon'

Tests:

slice
var result = example.slice(0, 3)
substr
var result = example.substr(0, 3)
substring
var result = example.substring(0, 3)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substr
substring

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
slice	13111414.0 Ops/sec
substr	13147877.0 Ops/sec
substring	13053052.0 Ops/sec

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

LLMs can make mistakes. Check important info.

The provided benchmark compares three JavaScript string methods: `slice`, `substr`, and `substring`. Each of these methods is used to extract parts of a string, but they have distinct behaviors, particularly in how they interpret their arguments.

### Options Compared

1. **slice(startIndex, endIndex)**
   - Extracts a section of a string based on the start and optional end indices.
   - If the end index is omitted, it takes the rest of the string from the start index.
   - Can accept negative indices, which count from the end of the string.

2. **substr(startIndex, length)**
   - Extracts a substring starting from the specified start index for a given length.
   - If length is omitted, it extracts the rest of the string from the start index.
   - The method has been deprecated in some environments but is still widely used.

3. **substring(startIndex, endIndex)**
   - Returns the part of the string between two indices.
   - If the end index is omitted, it extracts to the end of the string.
   - Unlike `slice`, it does not accept negative indices. If the start index is greater than the end index, it swaps them.

### Pros and Cons

#### `slice`
- **Pros:**
  - Supports negative indexing, which is useful for extracting parts from the end of a string.
  - More flexible in certain use cases.
  
- **Cons:**
  - Slightly more complex due to the additional arguments and flexibility.
  
#### `substr`
- **Pros:**
  - Simple syntax focusing on starting position and length.
  - Easy to understand for basic substring extraction.
  
- **Cons:**
  - Deprecated in some environments and not recommended for future use.
  
#### `substring`
- **Pros:**
  - Clear behavior when it comes to indices.
  - Intuitive for users who need to extract strings between two defined points.
  
- **Cons:**
  - Does not support negative indices, which limits its flexibility.
  - Slightly slower performance in certain conditions compared to `slice` and `substr`, as shown in the benchmarks.

### Benchmark Results

In the most recent benchmark results, the execution speeds were as follows:
- **substr**: 13,147,877 executions per second (fastest)
- **slice**: 13,111,414 executions per second
- **substring**: 13,053,052 executions per second

From these results, it appears that `substr` performed the best, followed closely by `slice`, and `substring` was slightly slower overall.

### Other Considerations

- **Performance**: The execution time can vary by JavaScript engine. It's essential to test in the environment where the code will run.
- **Readability**: While performance is significant, code maintainability and readability also matter. Using familiar and clear methods may be preferred in some cases, even if they are slightly slower.
- **Deprecation**: It's generally not advisable to use deprecated methods like `substr` as they might be removed in future versions of the language.

### Alternatives

- **Template Literals**: If the goal is to concatenate or interpolate strings, using template literals (with backticks) can be a more modern and clean approach.
- **Regular Expressions**: For more complex string manipulation, regular expressions provide powerful string handling capabilities.
- **String Methods**: Newer ECMAScript standards introduced several methods like `includes`, `startsWith`, and `endsWith`, which help with string handling beyond simple extraction.

Overall, the optimal method to use depends on the specific needs in terms of flexibility, clarity, and performance requirements.

Related benchmarks:

slice vs substr vs substring (with no end index) (version: 1)

Compares slice, substr and substring to each other when there is only a start index

Comparing performance of: slice vs substr vs substring

Created: one month ago by: Guest

Jump to the latest result

slice

substr

substring

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):