Benchmark: Performance Test: substring vs substr vs slice1

Script Preparation code:

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

Tests:

slice
var substring = string.slice(0, -1);
substring
var substring = string.substring(0, string.lenght-1);
substr
var substring = string.substr(0, string.lenght-1);

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

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The provided JSON represents a benchmark test that compares the performance of three different string manipulation methods: `slice`, `substring`, and `substr`. These methods are used to extract a portion of a string. The test focuses on extracting the last character from a given string.

**Options compared:**

1. **`slice`**: The `slice()` method returns a new string that includes only the selected characters, specified by their indices.
2. **`substring`**: The `substring()` method returns a new string that includes only the selected characters, specified by their start and end indices (both inclusive).
3. **`substr`**: The `substr()` method returns a new string that includes only the selected characters, specified by their start index (inclusive) and length.

**Pros and Cons:**

*   **`slice`**:
    *   Pros: Efficient, as it creates a new string without modifying the original.
    *   Cons: May incur overhead due to the creation of a new string object.
*   **`substring`**:
    *   Pros: More intuitive than `substr`, as it takes start and end indices, making it easier to extract a substring.
    *   Cons: May be slower than `slice` or `substr`, depending on the browser implementation.
*   **`substr`**:
    *   Pros: Compact syntax, making it easy to use for simple cases (e.g., extracting the last character).
    *   Cons: Can lead to performance issues if used with large strings, as it requires creating a new string object.

**Library and its purpose:**

In this benchmark, the `slice()`, `substring()`, and `substr()` methods are built-in JavaScript methods. They don't rely on any external libraries.

**Special JS feature or syntax:**

There is no special JS feature or syntax used in these test cases. The focus is solely on comparing the performance of the three string manipulation methods.

**Other alternatives:**

If you need to extract a portion of a string, consider using other methods like:

*   **`replace()`**: Can be used to replace characters at specific indices.
*   **Regular expressions**: Can be used to extract specific patterns from strings.

However, for simple cases like extracting the last character, `substr` is still a good choice.

In conclusion, this benchmark test provides valuable insights into the performance differences between `slice`, `substring`, and `substr`. By understanding these variations, developers can make informed decisions about which method to use in their own JavaScript applications.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.111 Safari/537.36

Browser/OS: Chrome 86 on Windows

View result in a separate tab

Test name	Executions per second
slice	9061192.0 Ops/sec
substring	4255301.5 Ops/sec
substr	4277198.0 Ops/sec

Related benchmarks:

Performance Test: substring vs substr vs slice1 (version: 0)

Comparing performance of: slice vs substring vs substr

Created: 4 years ago by: Guest

Jump to the latest result

slice

substring

substr

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):