Benchmark: Performance Test: substring vs subsstr vs slice

Script Preparation code:

var string = "I am the god of hellfire, and I ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffbring you..."

Tests:

slice
var substring = string.slice(17, 25);
substring
var substring = string.substring(17, 25);
substr
var substring = string.substr(17, 25);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring
substr

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:126.0) Gecko/20100101 Firefox/126.0

Browser/OS: Firefox 126 on Windows

View result in a separate tab

Test name	Executions per second
slice	1074014080.0 Ops/sec
substring	1172214016.0 Ops/sec
substr	1037505088.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its test cases.

**Benchmark Overview**

The benchmark is designed to compare the performance of three different methods for extracting a substring from a string: `slice()`, `substring()`, and `substr()`.

**Test Cases**

Each test case consists of a JavaScript code snippet that extracts a substring from a predefined string using one of the three methods. The substrings to be extracted are fixed (from index 17 to 25) in all cases.

Here's a brief explanation of each method:

1. **slice()**: `slice(start, end)` returns a new string containing the characters from `start` to `end-1`.
2. **substring()**: `substring(start, end)` returns a new string containing the characters from `start` to `end-1`. This method is similar to `slice()`, but it's specifically designed for extracting substrings.
3. **substr()**: `substr(index, length)` returns a new string containing the characters from `index` to `index+length-1`.

**Options Compared**

The benchmark compares the performance of these three methods in terms of execution time.

**Pros and Cons of Each Approach**

*   **slice() and substring():**
    *   Pros:
        *   Both are widely supported by modern browsers.
        *   They have a simple syntax and are easy to use.
    *   Cons:
        *   `substring()` is specifically designed for extracting substrings, so it might be optimized better than `slice()`.
*   **substr():**
    *   Pros:
        *   It's often faster than `substring()` because it uses an internal buffer to store the result, which can reduce memory allocation and copying overhead.
    *   Cons:
        *   It's less commonly used than `slice()` or `substring()`, so its performance might be less consistent across different browsers.

**Library Used**

None of these methods rely on any external libraries. They are built-in JavaScript functions.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax used in this benchmark.

**Other Alternatives**

If you wanted to extract a substring from a string, other alternatives could include using regular expressions (e.g., `string.match()` followed by array indexing) or string manipulation libraries like String.prototype.split() and String.prototype.join(). However, these approaches are not as efficient as the built-in `slice()`, `substring()`, and `substr()` methods.

Here's an example of how you could use the other alternatives:

```javascript
// Using regular expressions:
var substring = string.match(/.{17,25}/)[0];

// Or using String.prototype.split():
var parts = string.split('');
var substring = parts[17] + parts.slice(18, 25).join('');

// Or using String.prototype.indexOf() and array slicing:
var start = string.indexOf('...'); // '...' is the part of the original string that you want to slice off.
var end = start + 8; // The new index should be 8 characters after the start index.
var substring = string.slice(start, end);
```

Related benchmarks:

Performance Test: substring vs subsstr vs slice (version: 0)

Comparing performance of: slice vs substring vs substr

Created: 5 years ago by: Guest

Jump to the latest result

slice

substring

substr

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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